tag:blogger.com,1999:blog-64705430063141529622024-03-11T16:49:28.376+00:00The Happy PontistA blog from the UK about bridges and bridge designThe Happy Pontisthttp://www.blogger.com/profile/15252272118786667592noreply@blogger.comBlogger981125tag:blogger.com,1999:blog-6470543006314152962.post-3277209591293104782023-05-28T10:18:00.001+01:002023-05-28T10:18:13.540+01:00"Bridging the Tees", by Chris Davies<p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhlT0kVscAA2aAomU_yG9auS9OeYctWlOq4OodwSwOnvVut3UsouAnYeCgQr4SlgbaLRZnVY5X4wJ2wTlGGHNFU1oLlOxTrtYqIBs2F0QjFClc3Iw0Zwxa3NiQKsN6noxr5XMdz5qmEwhQVNVwY2wXOE6ABSiJ0ZXK-jMxoCg9Ktv06w6YsAvK0R2cSFw/s1392/20230520_100537.png" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="1017" data-original-width="1392" height="146" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhlT0kVscAA2aAomU_yG9auS9OeYctWlOq4OodwSwOnvVut3UsouAnYeCgQr4SlgbaLRZnVY5X4wJ2wTlGGHNFU1oLlOxTrtYqIBs2F0QjFClc3Iw0Zwxa3NiQKsN6noxr5XMdz5qmEwhQVNVwY2wXOE6ABSiJ0ZXK-jMxoCg9Ktv06w6YsAvK0R2cSFw/w200-h146/20230520_100537.png" width="200" /></a></div>Chris Davies very kindly supplied me with a copy of his book <i>Bridging the Tees</i> (self-published, 2023, 128pp). If you want a copy you will have to go direct to the source: he sells it on eBay for £20 + postage (softcover) or £30 + postage (hardcover) - just search for the title. Alternatively, you can email teesbridges@btinternet.com for details of how to buy it.<p></p><p>The author's aim was to create a book that describes and depicts the roughly fifty bridges that span the River Tees in Northern England. Unusually, the photographs are all taken by drone, giving a different (and very helpful) perspective compared to what many other books offer.</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgk5xdUXhGPP3qJZQgppOs8m65LHtjy-P3jX3JMR3OJ3BxG0saLy-CI8NxHNcNqOsf6WRAgJZU1OE65vNFgN9JktAmPKyNhG8yT_69qY9FNfTPpy95O3kzrdMpVyce0Hb_ojD32TIdC9TBbx03gc9sinwRZsCTiTBRHcYNsD_3Qor9gvOmpHdPoR4thWA/s1290/20230520_100550.png" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="977" data-original-width="1290" height="303" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgk5xdUXhGPP3qJZQgppOs8m65LHtjy-P3jX3JMR3OJ3BxG0saLy-CI8NxHNcNqOsf6WRAgJZU1OE65vNFgN9JktAmPKyNhG8yT_69qY9FNfTPpy95O3kzrdMpVyce0Hb_ojD32TIdC9TBbx03gc9sinwRZsCTiTBRHcYNsD_3Qor9gvOmpHdPoR4thWA/w400-h303/20230520_100550.png" width="400" /></a></div><p>I like this kind of book - a catalogue of the bridges of a single place. I've previously featured examples like <i><a href="https://happypontist.blogspot.com/2020/08/bridging-tweed-by-jim-lyon.html">Bridging the Tweed</a></i>, <i><a href="https://happypontist.blogspot.com/2022/05/thames-bridges-by-david-c-ramzan.html">Thames Bridges</a></i> and <i><a href="https://happypontist.blogspot.com/2018/03/danube-bridges-by-peter-gyukics.html">Danube-bridges</a></i>. It's a nice little genre all of its own. It should appeal both to pontists and to those with an interest in the local area and its history.</p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhD7aiZbeT7dgvj2gooh5buFH1zQLOs4Dfcljbrr4OaoEhnuw07Y5_V6DpJkeCl9zWgVoFVeenGky-AoFpacMtPWc-dZK-DB4IzSaPRXGW-ev8iNQWqLnzwoOe6A6pjr-m8XwMEtYmKWrOln9gGmIhDId_YFPU5FLF3xymOz3rtHeIjfPW0fHbZt80PWQ/s1340/20230520_100610.png" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1052" data-original-width="1340" height="314" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhD7aiZbeT7dgvj2gooh5buFH1zQLOs4Dfcljbrr4OaoEhnuw07Y5_V6DpJkeCl9zWgVoFVeenGky-AoFpacMtPWc-dZK-DB4IzSaPRXGW-ev8iNQWqLnzwoOe6A6pjr-m8XwMEtYmKWrOln9gGmIhDId_YFPU5FLF3xymOz3rtHeIjfPW0fHbZt80PWQ/w400-h314/20230520_100610.png" width="400" /></a></div><p></p><p>Davies's book opens with a useful discussion of the River Tees itself, both as a waterway and as a historic border (between the county of Durham and the North Riding of Yorkshire). Several pages discuss the history of bridge (and turnpike) building and maintenance, an important part of understanding how the Tees bridges each came to be, and under what conditions they remain.</p><p>The heart of the book lists the bridges from Tees Head to Teesmouth. Each is given the same space: two pages, one page of text facing one page with a photograph of the bridge.</p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj26IR4CrO6YD9HcSSAhb9Px0bnXoXLsxnP_UlROLqHJw-KjNxTyddy01PeVK9Jxy6xrg8FnEenSGL5_QMbqzANJVwyEyDmvYC4qgSRnEW0cELvlpauUNDMx2RKmYauFip97N_yJ_b1msTgHP5Bggj1RCoNT59o7uKTy-7Q6dXLVEhKva1Z_M_YdQ4d3A/s1313/20230520_100619.png" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="985" data-original-width="1313" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj26IR4CrO6YD9HcSSAhb9Px0bnXoXLsxnP_UlROLqHJw-KjNxTyddy01PeVK9Jxy6xrg8FnEenSGL5_QMbqzANJVwyEyDmvYC4qgSRnEW0cELvlpauUNDMx2RKmYauFip97N_yJ_b1msTgHP5Bggj1RCoNT59o7uKTy-7Q6dXLVEhKva1Z_M_YdQ4d3A/w400-h300/20230520_100619.png" width="400" /></a></div><p></p><p>The text gives the salient facts about each bridge, so far as they are known, and something of their history and context. The author has plainly done his research, and it's all clearly written and informative. The river is home to several important historic structures, such as Wynch Bridge, Barnard Castle Bridge, Whorlton Suspension Bridge, <a href="https://happypontist.blogspot.com/2013/11/teesside-bridges-2-newport-lift-bridge.html">Newport Bridge</a> and the <a href="https://happypontist.blogspot.com/2013/11/teesside-bridges-1-middlesbrough.html">Tees Transporter Bridge</a>. Important bridges that no longer exist are mentioned in passing, such as the Stockton and Darlington Railway suspension bridge which proved to be unsafe as soon as it was built. Of the modern bridges, the <a href="https://happypontist.blogspot.com/2013/11/teesside-bridges-4-infinity-bridge.html">Infinity Bridge</a> is of particular interest.</p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjsB4VHtQcW035zQA--Gae8dZqh2aIM5oLZFuTyc2UE4fHu4xWjSmZOTQbJd2zi54olKHCm-0VdDfoWN5UcPB4ea6n2b5O3KbuigcpqMaLcUlI2VRPDxXJ3xAEwNcgBq_m62EadE0-eZBDp8YtHfo-rSutqQVTFQ_3iO2RzwXqm_ufd6-nH0VoA6HH6qg/s1319/20230520_100601.png" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1014" data-original-width="1319" height="308" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjsB4VHtQcW035zQA--Gae8dZqh2aIM5oLZFuTyc2UE4fHu4xWjSmZOTQbJd2zi54olKHCm-0VdDfoWN5UcPB4ea6n2b5O3KbuigcpqMaLcUlI2VRPDxXJ3xAEwNcgBq_m62EadE0-eZBDp8YtHfo-rSutqQVTFQ_3iO2RzwXqm_ufd6-nH0VoA6HH6qg/w400-h308/20230520_100601.png" width="400" /></a></div><p>Many of the bridges were new to me, including quite a few that seem worth a visit. The author notes that the book was never intended to be an academically comprehensive reference work, but there's little doubt it is the definitive word on its topic. I enjoyed it.</p><p></p>The Happy Pontisthttp://www.blogger.com/profile/15252272118786667592noreply@blogger.com1tag:blogger.com,1999:blog-6470543006314152962.post-44043291417365667292022-10-23T20:03:00.004+01:002022-10-23T20:03:45.118+01:00Chisholm Trail Bridge, Cambridge<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjmtE1FVRpeMtup09tk6uA1Qe-9oQOL_PXDNfnCpfklsxgInZjT3xT55rMUtU3cyxyrwSBiSNC1f5fA-rK_DdyWQFZhM1T8kfVc6x9kBLzqFbkABKJvymizVEywVmmKFctVh4Cux5fXtKJhB5q8dlSNPOc0fwbc72SDktv6Kd3-mwdSzseYuzzCc2ujJQ/s1319/Chisholm1.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="710" data-original-width="1319" height="215" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjmtE1FVRpeMtup09tk6uA1Qe-9oQOL_PXDNfnCpfklsxgInZjT3xT55rMUtU3cyxyrwSBiSNC1f5fA-rK_DdyWQFZhM1T8kfVc6x9kBLzqFbkABKJvymizVEywVmmKFctVh4Cux5fXtKJhB5q8dlSNPOc0fwbc72SDktv6Kd3-mwdSzseYuzzCc2ujJQ/w400-h215/Chisholm1.jpg" width="400" /></a></div><p>This is the last of three interesting pedestrian bridges that I visited in Cambridge earlier this year, and the most recently completed of the trio.</p><p>Also known as the Abbey - Chesterton Bridge, this structure forms a key link in the "<a href="https://en.wikipedia.org/wiki/Chisholm_Trail_(Cambridge)">Chisholm Trail</a>", a new walking and cycling route promoted by campaigner Jim Chisholm which will eventually extend for some 26 km in length.</p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhh0i_lS0hJovM8uVgyMXPyt4sMy7JMpr7zeTJUmw2Mn85smZRPW3hwwOqFUqr_G7_D80XCUG9CyixGGCmk2BSyH1xDXN2x0l1xy22ygoBL3BZXrOp74Vgi8A1FO5m30SEVDcFx4Xfd6pQWA91JciJxFvtvdL0dMFwlXFym6vnkD6A5vemIbhMo8CVKCA/s1526/Chisholm12.jpg" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="1144" data-original-width="1526" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhh0i_lS0hJovM8uVgyMXPyt4sMy7JMpr7zeTJUmw2Mn85smZRPW3hwwOqFUqr_G7_D80XCUG9CyixGGCmk2BSyH1xDXN2x0l1xy22ygoBL3BZXrOp74Vgi8A1FO5m30SEVDcFx4Xfd6pQWA91JciJxFvtvdL0dMFwlXFym6vnkD6A5vemIbhMo8CVKCA/w200-h150/Chisholm12.jpg" width="200" /></a></div>The bridge was <a href="https://www.camcycle.org.uk/blog/2020/11/camcycle-thrilled-to-see-the-abbey-chesterton-bridge-lifted-into-place-and-already-uniting-local-communities/">installed in November 2020</a> and this part of the Trail was <a href="https://www.cambridgeindependent.co.uk/news/first-stage-of-chisholm-trail-walk-and-cycle-route-across-ca-9232415/">opened to the public on 23 December 2021</a>. The bridge was designed by <a href="https://www.knightarchitects.co.uk/bridges/abbey-chesterton-footbridge">Knight Architects</a>, and various engineering firms are cited on different websites: I understand that Atkins were first involved, then Skanska, and finally Milestone Infrastructure in the eventual design-and-build contract.<p></p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhMkvvTRdcOatHOTlbNxA6djwWbL9JcnlOOuUMCrsmYoy1o1fGr98aobg61oew9-SNlbe0mk-jZDWW4xQnhAlE4W2-duHJMHaU7zVHRzRO_j33-703k6Gk_64qoMCtkOKanaZZXvAr5n_RjAXlutJUIFUCWNcytwYD60QcH3GDAdNOBK-7yWVZWW2JjJw/s1526/Chisholm17.jpg" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="1144" data-original-width="1526" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhMkvvTRdcOatHOTlbNxA6djwWbL9JcnlOOuUMCrsmYoy1o1fGr98aobg61oew9-SNlbe0mk-jZDWW4xQnhAlE4W2-duHJMHaU7zVHRzRO_j33-703k6Gk_64qoMCtkOKanaZZXvAr5n_RjAXlutJUIFUCWNcytwYD60QcH3GDAdNOBK-7yWVZWW2JjJw/w200-h150/Chisholm17.jpg" width="200" /></a></div>The structure spans across the River Cam, and is 44m long and up to 4.9m wide. The original budget was £4.9m, although the cost <a href="https://cambridgeshire.cmis.uk.com/CCC_live/Document.ashx?czJKcaeAi5tUFL1DTL2UE4zNRBcoShgo=DJBMC5TjJYdndo4glBaD7V20ItCzxfd4Lxdh4WzXJ2MTu7g0UVCiRw%3D%3D&rUzwRPf%2BZ3zd4E7Ikn8Lyw%3D%3D=pwRE6AGJFLDNlh225F5QMaQWCtPHwdhUfCZ%2FLUQzgA2uL5jNRG4jdQ%3D%3D&mCTIbCubSFfXsDGW9IXnlg%3D%3D=hFflUdN3100%3D&kCx1AnS9%2FpWZQ40DXFvdEw%3D%3D=hFflUdN3100%3D&uJovDxwdjMPoYv%2BAJvYtyA%3D%3D=ctNJFf55vVA%3D&FgPlIEJYlotS%2BYGoBi5olA%3D%3D=NHdURQburHA%3D&d9Qjj0ag1Pd993jsyOJqFvmyB7X0CSQK=ctNJFf55vVA%3D&WGewmoAfeNR9xqBux0r1Q8Za60lavYmz=ctNJFf55vVA%3D&WGewmoAfeNQ16B2MHuCpMRKZMwaG1PaO=ctNJFf55vVA%3D">went up to £6.9m</a>, working out at around £35,000 per square metre of deck, although some of that cost will relate to ramps and landscaping at either end. The bridge reportedly weighs 140 tonnes, and it was fabricated by <a href="http://www.shstructures.com/projects/abbey-chesterton-bridge/">SH Structures</a>.<p></p><p>The bridge was shortlisted for a <a href="https://steelconstruction.org/resources/structural-steel-design-awards/">2022 Structural Steel Design Award</a>, and it's easy to see why. The design is described by Knight Architects as an <i>"ornate lattice U-beam with a structural pattern wrapped around the deck"</i>, and the combination of complexity and clarity in the bridge's appearance makes an excellent first impression.</p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgsV9aKFvPcl3QYUVh42-sF-BZmTjN2_1oj84Xrg8hVlHQ2TEJxARhrIbVo0KKTyzQiLd2sVTaZ7IH6-ITJ8arUw2Y7APOCFzd-Hs24FRO4q9GKQGt-g4GqXIkR8gvuj8Eo-57yIMAlcOPugVzTtPLz6-Y_vvZGIaK7Xsd2H-sAJFn3gjlxjEnvjZWxPw/s1526/Chisholm4.jpg" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="1144" data-original-width="1526" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgsV9aKFvPcl3QYUVh42-sF-BZmTjN2_1oj84Xrg8hVlHQ2TEJxARhrIbVo0KKTyzQiLd2sVTaZ7IH6-ITJ8arUw2Y7APOCFzd-Hs24FRO4q9GKQGt-g4GqXIkR8gvuj8Eo-57yIMAlcOPugVzTtPLz6-Y_vvZGIaK7Xsd2H-sAJFn3gjlxjEnvjZWxPw/w200-h150/Chisholm4.jpg" width="200" /></a></div>I approached from the north side. A little to the west of Cheney Way, a footpath connects Fen Road to the riverside path. Walking eastwards along that path towards the new footbridge, the river is dominated by a lattice truss railway bridge, which carries a fully operational railway line.<p></p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhEiYyuKdKS_ygQo2qo1CfyETNY91M9AkudQNGXR5-l7ue69J86s2vl6GOM3bV0S0TDZD9ovu47NRKopcRcERcAZQQCAS-T-oFqJR9NAZ_2fhIjFwds5QDOWGCrMDRWCUeGAx2M3GhuM739D8QTcYJYNJeXijdwFUbsj7qcQFoI49zNXB2hVDE-FUgdpQ/s1320/Chisholm3.jpg" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="990" data-original-width="1320" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhEiYyuKdKS_ygQo2qo1CfyETNY91M9AkudQNGXR5-l7ue69J86s2vl6GOM3bV0S0TDZD9ovu47NRKopcRcERcAZQQCAS-T-oFqJR9NAZ_2fhIjFwds5QDOWGCrMDRWCUeGAx2M3GhuM739D8QTcYJYNJeXijdwFUbsj7qcQFoI49zNXB2hVDE-FUgdpQ/w200-h150/Chisholm3.jpg" width="200" /></a></div>The route up onto the bridge is awkward (and visible on Google maps, if my photos don't make it clear). There are steps up from the riverside path, and a cycle ramp that doubles back with a very tight bend. The proximity of a railway level crossing rules out a direct connection to Fen Road, and it seems there's no connection through what looks like new housing, which I think is unfortunate.<p></p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgV1exAHnF50ZZqlwuCABSa_upcLaZv5-U9wRayhMf5omqyBeKs8DMXdDDGgzd9jdhm-5V_CxJeEpzMR_0eGdIvqClTt4V6FHm3cY_tFQCycbnSPRpd2c8ZxbVPMtQO7sk1spAgHA1mmzqOmm7jW1QHHfSzMq8xjAuxNjatjP_UmH33KBJVK0kmfQz4gA/s1465/Chisholm2.jpg" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="777" data-original-width="1465" height="106" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgV1exAHnF50ZZqlwuCABSa_upcLaZv5-U9wRayhMf5omqyBeKs8DMXdDDGgzd9jdhm-5V_CxJeEpzMR_0eGdIvqClTt4V6FHm3cY_tFQCycbnSPRpd2c8ZxbVPMtQO7sk1spAgHA1mmzqOmm7jW1QHHfSzMq8xjAuxNjatjP_UmH33KBJVK0kmfQz4gA/w200-h106/Chisholm2.jpg" width="200" /></a></div>Passing below the bridge along the riverside, the latticework stiffening to the bridge can be seen, and is a little reminiscent of a Pier Luigi Nervi grid-shell, a contemporary echo of the adjacent rail span. The footbridge appears to be an efficient modern design broadly in a Warren truss configuration. A closer look is puzzling, as the truss has an obvious top chord, its upper boom, but no obvious bottom chord. It's unclear how the truss forces are carried, and quite how the lattice grid works structurally.<p></p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjdrqcZOPcehnfxs1HpDxX3PKYTa7jnYKVbThMEiFOiCRWqZpsAMw2VrA4YUTxgNy8y6tUz7HFfrHZYz5yYOt7OEHYBffYg-fk3TR0BPSyYy3XwEA6xoop98fLtEJFIg8454phnwjQERfiE2Z-9WWu0xRCcOb1Q8Txsu588mbpKsfaLDyDeyas10fXjKA/s1526/Chisholm5.jpg" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="1144" data-original-width="1526" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjdrqcZOPcehnfxs1HpDxX3PKYTa7jnYKVbThMEiFOiCRWqZpsAMw2VrA4YUTxgNy8y6tUz7HFfrHZYz5yYOt7OEHYBffYg-fk3TR0BPSyYy3XwEA6xoop98fLtEJFIg8454phnwjQERfiE2Z-9WWu0xRCcOb1Q8Txsu588mbpKsfaLDyDeyas10fXjKA/w200-h150/Chisholm5.jpg" width="200" /></a></div>Once up onto the bridge, the answers begin to emerge. The bridge deck is segregated between cycle and footways, which is probably sensible given the way that some Cambridge cyclists like to whizz around. This explains the asymmetry in the parapet design. There are perforated stainless steel plates filling the triangular openings in the trusses, folded over at the top to provide a stiff upper edge. On the pedestrian-only side of the deck, that edge is 1.1m above deck level, and it is 1.4m on the cycle side.<p></p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgWvXnQsT0yWejZIs_W-3-IPssqeeKgzg75hMbwU9TuthZVwJsu-XKiaEruhf52W1vGIGGfhh3qcG7pfCnGpxQBPd8zyhH19y5PiEIiTRzaFnze-KKwLI03gTm4cZ5XJsY4R0dZzmqEarunsBCsYUz3C7mrROUDUcSumIlx4yu8sZc-lnpo4Q4UGlnurw/s1526/Chisholm18.jpg" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="1144" data-original-width="1526" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgWvXnQsT0yWejZIs_W-3-IPssqeeKgzg75hMbwU9TuthZVwJsu-XKiaEruhf52W1vGIGGfhh3qcG7pfCnGpxQBPd8zyhH19y5PiEIiTRzaFnze-KKwLI03gTm4cZ5XJsY4R0dZzmqEarunsBCsYUz3C7mrROUDUcSumIlx4yu8sZc-lnpo4Q4UGlnurw/w200-h150/Chisholm18.jpg" width="200" /></a></div>My feeling of joy in the bridge design began to take a nose-dive at about this point. The first thing that drew my attention was a gap in the top chord of the truss. Err, sorry, "truss". There are regular narrow gaps in this element, with what look like little dowel bars hidden away inside. This seemed odd. For the non-engineers amongst my readers, the top chord on a single-span truss carries a compression force, while the bottom chord (mysteriously absent here), carries tension. It's not easy to carry compression if you leave a gap though!<p></p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgXEs26ZHH25MKz0iXETa5DwBQoGDFaovG_1pboLy-vYsCyES9HnZfEL89KSmV2x81Jp84nmuylTaVkBjph164zxocUdSX4LJPOFIMOHcbrtw0NRTtVKermEX2W_n0EFYkDv9zB5R7kuxEGf9XINiG0iPim_VAO8Das-v-U_lRI0PNkVi-d6udteyG_Tw/s1526/Chisholm19.jpg" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="1144" data-original-width="1526" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgXEs26ZHH25MKz0iXETa5DwBQoGDFaovG_1pboLy-vYsCyES9HnZfEL89KSmV2x81Jp84nmuylTaVkBjph164zxocUdSX4LJPOFIMOHcbrtw0NRTtVKermEX2W_n0EFYkDv9zB5R7kuxEGf9XINiG0iPim_VAO8Das-v-U_lRI0PNkVi-d6udteyG_Tw/w200-h150/Chisholm19.jpg" width="200" /></a></div>There seem to be two possibilities for how this bridge works structurally. One is that the dowel bars do indeed transfer compression, but the gaps are needed to reduce bending restraint in the upper structural member i.e. to act as "pins" allowing local rotation. I can only say that I wouldn't do it like that, and I don't think this is the case anyway.<div><br /></div><div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEibkMwxy4fGeXDY5H1GHkZ1qd0_oWAaUxLRaeo5elmaFeqgEfz1GPqu1XHTUUd2v5k58xrw4cUtvqB6PG99y80C1vBEtO-bctnAEjjhk2oN1bLnaZcGiSIZUAvkQc6UuTRXZjpjMv3a-XvHRHZdHfkS8eqH9rpfcTUd_G67QhDnq17jrZVxU5Lx478QcA/s1526/Chisholm13.jpg" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="1144" data-original-width="1526" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEibkMwxy4fGeXDY5H1GHkZ1qd0_oWAaUxLRaeo5elmaFeqgEfz1GPqu1XHTUUd2v5k58xrw4cUtvqB6PG99y80C1vBEtO-bctnAEjjhk2oN1bLnaZcGiSIZUAvkQc6UuTRXZjpjMv3a-XvHRHZdHfkS8eqH9rpfcTUd_G67QhDnq17jrZVxU5Lx478QcA/w200-h150/Chisholm13.jpg" width="200" /></a></div>The other possibility is that this is not a truss at all, and that the bridge is in fact a box girder with a curved belly - and the triangulated "truss" elements are just an incredibly expensive way to support the parapet handrails. This is what I think is the case, and I suspect it's an artefact of the design-and-build process i.e., a compromise added to make the structure easier to analyse, design or fabricate. No gaps are shown on the planning consent drawings.<p></p><p>I wouldn't like to be the maintenance engineer charged with trying to paint the faces inside each gap at some point in the future.</p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgsCuUV7PRJdmHOiOkMD4hRCINEHYdgTPyyABMyirLIdqylP4NuiYxB1acrbTtdh0YTfXso142-pvOz5YzmhDpfFJlm-DAXRVKEFaPvhucXKZXri9BL27ZSXIpHhL4lVBIjhwtx-hJkDvpZdc6G_e9ul1Y1ugi6WzJuV8kusitCFEeB7PNcmgAf9qwvbQ/s1526/Chisholm9.jpg" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="1144" data-original-width="1526" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgsCuUV7PRJdmHOiOkMD4hRCINEHYdgTPyyABMyirLIdqylP4NuiYxB1acrbTtdh0YTfXso142-pvOz5YzmhDpfFJlm-DAXRVKEFaPvhucXKZXri9BL27ZSXIpHhL4lVBIjhwtx-hJkDvpZdc6G_e9ul1Y1ugi6WzJuV8kusitCFEeB7PNcmgAf9qwvbQ/w200-h150/Chisholm9.jpg" width="200" /></a></div>The second feature of the bridge that drew my attention is the relationship between the parapet treatment within the length of the "trusses", and its treatment beyond them. The upper edge of the truss curves down at its ends, which is structurally rational for a truss and visually coherent in any case. However, it curves down below the height required for parapet containment of pedestrians and cyclists. The upper edge line of the parapets therefore passes above the upper edge line of the "trusses" at their ends, resulting in a need for parapet elements very different in form to the perforated infill panels.<p></p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgTRx0hjQJ5-R9RfpFDIBwgGK2AaVMHpaA_VYwl1Wge9CaQoaGVwCEGS5F_Oe0P6r9g-cVJmPLmyfIe-QEl4Z9_55dt3zfDfeoNIP7LNaycLPM80m3IBgVk0IshYkjzMFLe_nbL5MuQFmFe-Ok9TlJsDT1x0npRmOqhE3BrNmBIER00EYcTs0M29sWLCw/s1526/Chisholm16.jpg" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="1144" data-original-width="1526" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgTRx0hjQJ5-R9RfpFDIBwgGK2AaVMHpaA_VYwl1Wge9CaQoaGVwCEGS5F_Oe0P6r9g-cVJmPLmyfIe-QEl4Z9_55dt3zfDfeoNIP7LNaycLPM80m3IBgVk0IshYkjzMFLe_nbL5MuQFmFe-Ok9TlJsDT1x0npRmOqhE3BrNmBIER00EYcTs0M29sWLCw/w200-h150/Chisholm16.jpg" width="200" /></a></div>It's straightforward as a relationship between two intersecting lines, one curved relative to the bridge deck level, and one parallel to the bridge deck level. However, the detailing is quite awkward, and it feels like the parapet sections at the ends of the bridge are afterthoughts, with no obvious relationship to those in the middle.<p></p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiYFAmBARjwrnEHlrhOeQgTZZTjTybRWDcLwQeEwP-bc1uEiWXO_h92Iz5PKr0BIYTGVliX6aMsdFuMWmFzDqBJxBjeHvKm7hMFgWScU0WdkVAU30j_NhEppwkCPa6BKye3maMmqSL79tbrEK-77PZixdHjn3WrYb8xsgLOekE6gO-xIqX_otaMxrEgJg/s1526/Chisholm10.jpg" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="1144" data-original-width="1526" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiYFAmBARjwrnEHlrhOeQgTZZTjTybRWDcLwQeEwP-bc1uEiWXO_h92Iz5PKr0BIYTGVliX6aMsdFuMWmFzDqBJxBjeHvKm7hMFgWScU0WdkVAU30j_NhEppwkCPa6BKye3maMmqSL79tbrEK-77PZixdHjn3WrYb8xsgLOekE6gO-xIqX_otaMxrEgJg/w200-h150/Chisholm10.jpg" width="200" /></a></div>Beyond the ends of the bridge, there's a classic bit of "architecture", that is the derivation of form from what is visually rational rather than structurally rational. This comes in the form of a series of concrete panels that continue the line of the "truss" curve downwards. There is no longer any force to be transmitted in the structure (we're off the end of the bridge at this point), but it results in yet another variation in the parapet form. It's lovingly detailed, yes, but a consequence of the formalist geometry of the bridge composition, not of anything else.<p></p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgjZXlEb9f6W5ms621o16NiDZvaBk9hJPOt_ia6jRmYV8TnLEX_KZ1NDJB4jwUsTJcg6AI3Xx10RA8Viauz5Ivb6dDkpt1jzoEEZT71864DYSRI6wDyPhmZcC6jGX3aX5xMSJyU57ZthVN9G0mXpPHuClHlyRgDvUntYE0VTX7vbHdWUSxDpOQ_01gCNw/s1320/Chisholm11.jpg" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="990" data-original-width="1320" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgjZXlEb9f6W5ms621o16NiDZvaBk9hJPOt_ia6jRmYV8TnLEX_KZ1NDJB4jwUsTJcg6AI3Xx10RA8Viauz5Ivb6dDkpt1jzoEEZT71864DYSRI6wDyPhmZcC6jGX3aX5xMSJyU57ZthVN9G0mXpPHuClHlyRgDvUntYE0VTX7vbHdWUSxDpOQ_01gCNw/w200-h150/Chisholm11.jpg" width="200" /></a></div>At each end of the bridge, there is a staircase down to the riverside footpath, wrapped around stepped landscaping. The bridge's concrete wing walls are a little austere, but they were remarkably free of graffiti when I visited.<p></p><p>Despite everything, I was surprised to find I still liked this bridge. Even if the structural form is seriously compromised, the visual identity remains attractive.</p><p>However, in a time when the evangelists for Net Zero are pushing us to make more efficient use of material (to "use less stuff", in the words of one), this probably isn't a design that anyone should wish to copy. One lesson that could be learned from this bridge is that a form that is visually attractive may be problematic to deliver if it isn't rooted directly in a sensible structural form (here: the lack of bottom chords to the truss).</p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgplOw_WAkfjASH_-MvovpAYm5TzxrFg2nb4Ouk-jJWLLdnoJjb-Yxr_adLMommpvdYeFn1U6pbjLyQyWusqZ7hhz-wgLZzp7e9bhmR9XXvo6Gh2Ua60Z_eyFtHL_tEjTXkR48ICst-S5NDvLptGKRXO8GtT_zVGBeo_TMeA1tK5KnmzDoWtDmDawrLHA/s1526/Chisholm8.jpg" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="1144" data-original-width="1526" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgplOw_WAkfjASH_-MvovpAYm5TzxrFg2nb4Ouk-jJWLLdnoJjb-Yxr_adLMommpvdYeFn1U6pbjLyQyWusqZ7hhz-wgLZzp7e9bhmR9XXvo6Gh2Ua60Z_eyFtHL_tEjTXkR48ICst-S5NDvLptGKRXO8GtT_zVGBeo_TMeA1tK5KnmzDoWtDmDawrLHA/w200-h150/Chisholm8.jpg" width="200" /></a></div>If the Abbey Chesterton Footbridge tells us anything else about how to deliver a good quality bridge, an alternative lesson is simply about how to avoid letting the procurement process leading to compromise. With the increasing impetus towards decarbonisation and the pressing need for higher quality design more generally, it's clear we really need to find better ways to connect and incentivise the various participants in the construction supply chain.<p></p><p><b>Further information:</b></p><p></p><ul style="text-align: left;"><li><a href="https://goo.gl/maps/L9EFEGTyR8FkJVty5">Google maps</a></li><li><a href="https://www.whatdotheyknow.com/request/373931/response/914611/attach/4/EIR%207247%20APP4.pdf?cookie_passthrough=1">Cambridgeshire Quality Panel Review, March 2016</a></li><li><i><a href="https://www.newsteelconstruction.com/wp/bridge-adds-to-cambridge-walking-and-cycling-trail/">New Steel Construction</a></i>, January 2021</li></ul><p></p></div>The Happy Pontisthttp://www.blogger.com/profile/15252272118786667592noreply@blogger.com3tag:blogger.com,1999:blog-6470543006314152962.post-83944798275922083542022-08-05T16:59:00.000+01:002022-08-05T16:59:09.456+01:00Riverside Footbridge, Cambridge<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiHxtQTWY6nnFmfjpBR3s4p2wMjz6NM7nZ841yDRsf-PG9NZ_Oxy-TnbLtu42a4EsFpuQHEM4QLXUmLlcLMqGivNYvs-IlJsPm_QRI-oUtPBptAslWTNLb5gsjzQdO2tNu6o9PeMR_Yj6CzLhUtYPd6aR6NMVgbpKj_Qkuo5qfvYJRMl-ZW1MoiEN9D5Q/s1156/Riverside12.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="867" data-original-width="1156" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiHxtQTWY6nnFmfjpBR3s4p2wMjz6NM7nZ841yDRsf-PG9NZ_Oxy-TnbLtu42a4EsFpuQHEM4QLXUmLlcLMqGivNYvs-IlJsPm_QRI-oUtPBptAslWTNLb5gsjzQdO2tNu6o9PeMR_Yj6CzLhUtYPd6aR6NMVgbpKj_Qkuo5qfvYJRMl-ZW1MoiEN9D5Q/w400-h300/Riverside12.jpg" width="400" /></a></div><p>This is another interesting pedestrian bridge that I found on a visit to Cambridge earlier this year.</p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjJOAWoAlOIEic8vasqNyDHbvNwWhXkm5pd8Qrtsid26GzCjZe5m2GCX5hWCLGYw6NrqZbKLRJNYE0MAU6_3Auw2hDv5oaxt_Qm01KoWcSdHlhlyjEzqd05osmmkhLlzPEmv1Bdm7xDs2SZwFH-5FnJJVaddJiIjgEpgl7CWFu1wjWsGo0K2ARGBV5Zqw/s1156/Riverside1.jpg" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="867" data-original-width="1156" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjJOAWoAlOIEic8vasqNyDHbvNwWhXkm5pd8Qrtsid26GzCjZe5m2GCX5hWCLGYw6NrqZbKLRJNYE0MAU6_3Auw2hDv5oaxt_Qm01KoWcSdHlhlyjEzqd05osmmkhLlzPEmv1Bdm7xDs2SZwFH-5FnJJVaddJiIjgEpgl7CWFu1wjWsGo0K2ARGBV5Zqw/w200-h150/Riverside1.jpg" width="200" /></a></div>The Riverside Footbridge spans the River Cam and its flood plain, a little way north of the city centre.<p></p><p>A design competition was held in 2003-4 for the site, with six teams shortlisted. The winner was Whitbybird with Gerry Judah, with Royal Haskoning as runner-up. The competition entries are visible on the <a href="https://www.camcycle.org.uk/magazine/newsletter53/article1/">Cambridge Cycling Campaign website</a> (the unbuilt entry from Marks Barfield and Babtie is also <a href="https://marksbarfield.com/projects/cambridge-footbridge/">here</a>).</p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhJwdNzKz5zv2PMWfXO5LmKLFZHYa8RjqZuHu8x64LKHzpbaHIF8TS4FoMspb45WTVJ9idnydQaPr-u0HwpEOwJ_SDoHYBQr8i6Kvv2s-ozFl0W1F428-hS-4K0ousnUe9OXR8bTeQM3vIkTzlopkoJCi2oSzmzYPCSMspXnkCAJXiFbf4t6GDhAU-uTA/s1156/Riverside6.jpg" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="867" data-original-width="1156" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhJwdNzKz5zv2PMWfXO5LmKLFZHYa8RjqZuHu8x64LKHzpbaHIF8TS4FoMspb45WTVJ9idnydQaPr-u0HwpEOwJ_SDoHYBQr8i6Kvv2s-ozFl0W1F428-hS-4K0ousnUe9OXR8bTeQM3vIkTzlopkoJCi2oSzmzYPCSMspXnkCAJXiFbf4t6GDhAU-uTA/w200-h150/Riverside6.jpg" width="200" /></a></div>The bridge was opened to the public on 5th June 2008, and carries pedestrians and cyclists on segregated paths. To the west of the river, one long structure carries users across the river floodplain, while on the east, the bridge ramp runs southwards parallel to the river.<p></p><p>One thing I found really strange about this layout is there is no easy access to the riverside on the west, and no easy way off the bridge to the north on the east side. A couple of staircases would have solved both issues.</p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhWJsSu1GYLDTm574uFh2Cgli5dGbQdAKcpdyB5MmT0nOsd0DsXwuE2XqpwOogX8h5QZIg96RzZgswsow-Xkote9LzzS9pEyzUG6aGZCrEbS21EfQVk5QQFKV8JyrYrLZQ3KxGaFsGPbh3Ko9mDmMraG_YSe5EzH31E4JC0_bH7JJELEgzD1zVVf6TKsQ/s1198/Riverside17.jpg" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="693" data-original-width="1198" height="116" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhWJsSu1GYLDTm574uFh2Cgli5dGbQdAKcpdyB5MmT0nOsd0DsXwuE2XqpwOogX8h5QZIg96RzZgswsow-Xkote9LzzS9pEyzUG6aGZCrEbS21EfQVk5QQFKV8JyrYrLZQ3KxGaFsGPbh3Ko9mDmMraG_YSe5EzH31E4JC0_bH7JJELEgzD1zVVf6TKsQ/w200-h116/Riverside17.jpg" width="200" /></a></div>The design is at first glance one of a very particular type of white-painted steel arch structures popularised by Santiago Calatrava, and adopted by almost everyone else. In particular, it seems to owe something to Whitbybird's earlier <a href="https://happypontist.blogspot.com/2010/03/manchester-bridges-5-merchants-bridge.html">Merchants Bridge</a>, in Manchester.<p></p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj_-TDr1MvE1nCYu8Z6IpfVYF0Gs8_6Pn3UMYGLY7AKzvFmwi1VzL-6a5ri08AamsB3rf3R-2WNBglvQWu7aLa49dBejrJYoBmqCPDSmPpGF6p9m9ge6tiNoW4zT9MQJLWBINK_IzgEPv0mDz7wkhioUV0HB0P5y7HfXGLKKmyzY6OKOSai_TrwXHbcnQ/s1156/Riverside7.jpg" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="867" data-original-width="1156" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj_-TDr1MvE1nCYu8Z6IpfVYF0Gs8_6Pn3UMYGLY7AKzvFmwi1VzL-6a5ri08AamsB3rf3R-2WNBglvQWu7aLa49dBejrJYoBmqCPDSmPpGF6p9m9ge6tiNoW4zT9MQJLWBINK_IzgEPv0mDz7wkhioUV0HB0P5y7HfXGLKKmyzY6OKOSai_TrwXHbcnQ/w200-h150/Riverside7.jpg" width="200" /></a></div>On closer examination, it's quite a bit different from the "classic" tilted arch footbridge although clearly derived from that concept.<p></p><p>The tubular steel arch spans across the river onto thrust foundations. Below deck level, the slender arch member is welded to much larger angled plinths, which I suspect must work quite hard under varying thermal conditions.</p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhgZOuVot78XBvGdiygnM_JwzUFw2lVuV-nE2PuO3q1o65j8rwVrJWIEWuN7NjNu71lFbGMpC6UheEMlfH47xEbnYhKoveSV3_f3TQrVdR4r6czX95BUcKuYoa59k8mVwyI1oBhjsJh-7vvE9xMEHHskLxXkzuv4kL4l7XipCdrTDmfARjBbDx_Dk589g/s1156/Riverside3.jpg" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="867" data-original-width="1156" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhgZOuVot78XBvGdiygnM_JwzUFw2lVuV-nE2PuO3q1o65j8rwVrJWIEWuN7NjNu71lFbGMpC6UheEMlfH47xEbnYhKoveSV3_f3TQrVdR4r6czX95BUcKuYoa59k8mVwyI1oBhjsJh-7vvE9xMEHHskLxXkzuv4kL4l7XipCdrTDmfARjBbDx_Dk589g/w200-h150/Riverside3.jpg" width="200" /></a></div>The deck carrying the cycleway sits to the north of the arch, suspended from it by steel braces. Cranked horizontal cross-ribs correspond to each brace, running back below the arch to support the footway deck. The cycle deck is a closed steel box-girder, providing torsional restraint to the whole system, while the footway deck is an open-framed system.<p></p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiqbWLxuECXOG7zG1dTIHRyfQkmB7sks5uO6MHDR2xmZ7teJb7XUCvl4o3jtPIqQLs56H_mDP2_h3lEKsSPUzuTjYEDDCEXfKx2oFHCZWpNETmH4G71pxvpksXLAup0OgWODKOI_VdHIHO3pW8PtTWGZDt2d8b74p0jTlGJyRtoJgz8Y2-3tFqQji-bgA/s1156/Riverside14.jpg" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="1156" data-original-width="867" height="200" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiqbWLxuECXOG7zG1dTIHRyfQkmB7sks5uO6MHDR2xmZ7teJb7XUCvl4o3jtPIqQLs56H_mDP2_h3lEKsSPUzuTjYEDDCEXfKx2oFHCZWpNETmH4G71pxvpksXLAup0OgWODKOI_VdHIHO3pW8PtTWGZDt2d8b74p0jTlGJyRtoJgz8Y2-3tFqQji-bgA/w150-h200/Riverside14.jpg" width="150" /></a></div>The cross-ribs are suspended from steel bars which hang vertically below the arch at intervals. The hangers, struts and cross-ribs form a series of triangles spaced evenly along the length of the arch, a highly formal composition that then seems to determine the overall geometry of the structure. The cycleway deck forms a smooth curve in plan, but the footway deck does not, its geometry seeming much less logical. Together, it's visually complex, and to my eye a little uncomfortable.<p></p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhJx95500X8DAWJOAq6uFcbYKBze9nu6nGlQ05w60wQ-5eJD6e_jMmQA524FKbjOz-Wb2jMxQ2FaOA9x6NZNM1egRr2AzJhQg9xyraIzctBe8YCdVZPB5VkRdrPxURIv3g4HF11RFmQVcRJZTSXGWZ4ubXqC7KLxQsDgISxsQwipM8rv8JNgeGu23EFNA/s1156/Riverside9.jpg" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="867" data-original-width="1156" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhJx95500X8DAWJOAq6uFcbYKBze9nu6nGlQ05w60wQ-5eJD6e_jMmQA524FKbjOz-Wb2jMxQ2FaOA9x6NZNM1egRr2AzJhQg9xyraIzctBe8YCdVZPB5VkRdrPxURIv3g4HF11RFmQVcRJZTSXGWZ4ubXqC7KLxQsDgISxsQwipM8rv8JNgeGu23EFNA/w200-h150/Riverside9.jpg" width="200" /></a></div>The cycleway deck is fixed to the arch supports, and the ramp extensions are continuous, with no joints until their far ends. The approach ramps are supported on steel piers via sliding bearings. The piers on the west approach are "7"-shaped, and although they are pleasing enough, when seen together with the deck steelwork, the underside is rather messy.<p></p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEha0VdGpHEvyY_zzoU3saLzbsPzsYVnB-67eG2K_hSEqHi1zJfRwq808D5Y97oSk0ITgIZeFk7H73-Vweme7JHMareuoITkIrPDElhDUP1J929WTc6sgTUJU92eGdzDFZwP5q4gBWF61pz9aKYvuBqLaDpOnE5aZMI3ohXQIfhUmt2ybakfn8ic4sqcmw/s1156/Riverside5.jpg" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="867" data-original-width="1156" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEha0VdGpHEvyY_zzoU3saLzbsPzsYVnB-67eG2K_hSEqHi1zJfRwq808D5Y97oSk0ITgIZeFk7H73-Vweme7JHMareuoITkIrPDElhDUP1J929WTc6sgTUJU92eGdzDFZwP5q4gBWF61pz9aKYvuBqLaDpOnE5aZMI3ohXQIfhUmt2ybakfn8ic4sqcmw/w200-h150/Riverside5.jpg" width="200" /></a></div>The input from the sculptor, Gerry Judah, is minimal, and seems to mainly consist of two circular platforms semi-attached to the western ramp, like pimples (<a href="https://www.camcycle.org.uk/magazine/newsletter61/article17/">the designers called them "buds"</a>). I say "semi"-attached, as they are mostly structurally independent except for small cleats which I'm guessing contribute to their lateral stability.<p></p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgyQtPdeKItQi3FtqOwK9B5m7q2j5wyfNXclNmIsMyKp1dnXbIkWJwxVjFhgmQXNYExswNpLIQcVlD8Srt7cyyVCXZ0E383rDvuzMBpv5nvqNgODzfjQFi-c1DrloA2p97tN3_V2wtRvAGhDlIcP_IlP6QTEPeXfHtut45EaQXTqNUWsR_pP15Kd6TkdA/s1200/Riverside4.jpg" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="1200" data-original-width="900" height="200" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgyQtPdeKItQi3FtqOwK9B5m7q2j5wyfNXclNmIsMyKp1dnXbIkWJwxVjFhgmQXNYExswNpLIQcVlD8Srt7cyyVCXZ0E383rDvuzMBpv5nvqNgODzfjQFi-c1DrloA2p97tN3_V2wtRvAGhDlIcP_IlP6QTEPeXfHtut45EaQXTqNUWsR_pP15Kd6TkdA/w150-h200/Riverside4.jpg" width="150" /></a></div>They feel a little like an afterthought, and the space they provide, with piddly little circular benches and pointless masts, isn't sufficiently pleasant to justify the investment that clearly went into detailing them.<p></p><p>If the underside of the approach ramps is untidy, the underside of the main span is just plain unsightly. From down here you get the best view of a tie bar that connects the ends of the arches and which just adds to the visual clutter.</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiXWGyKLgVyH507v3yGANBvAQ8sLfC9jILr6GE2YyeJK4Lot-f16GfNe_S00lXmiptiS-I6vh_1KrWUVSb4cLdYklb1UImTRtBkK9905_bsQz-lDU3DipcbWgUc8oZUhgUb8Q7PyIsgJALEzRZGU9LzCUwZ0JJ_1URUJDLEGDvL2xerxbAFaD2b6OAszg/s1156/Riverside8.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="867" data-original-width="1156" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiXWGyKLgVyH507v3yGANBvAQ8sLfC9jILr6GE2YyeJK4Lot-f16GfNe_S00lXmiptiS-I6vh_1KrWUVSb4cLdYklb1UImTRtBkK9905_bsQz-lDU3DipcbWgUc8oZUhgUb8Q7PyIsgJALEzRZGU9LzCUwZ0JJ_1URUJDLEGDvL2xerxbAFaD2b6OAszg/w400-h300/Riverside8.jpg" width="400" /></a></div><p>One day, people will realise quite how bad these white tubular steel bridges look after a few years if allowed to accumulate dirt rather than being kept clean.</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiAeHi1a1jmFNVdojb8DBwlSVCc7gvWWPnf_USXfeBiVZXyfKaBi0xrenAfGCLV9LWsZHrM9yk08xwcqhNM81geXVHuaQYZNdx25mFc-_n4RobRjZWlJ1JkZE07BlJCyC7yjBDKFCI-F9wfFLPcGpCyHNeqHYIfEJRUUGeiqLSDWs-eObQHzh2t1ruoYQ/s1156/Riverside11.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="867" data-original-width="1156" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiAeHi1a1jmFNVdojb8DBwlSVCc7gvWWPnf_USXfeBiVZXyfKaBi0xrenAfGCLV9LWsZHrM9yk08xwcqhNM81geXVHuaQYZNdx25mFc-_n4RobRjZWlJ1JkZE07BlJCyC7yjBDKFCI-F9wfFLPcGpCyHNeqHYIfEJRUUGeiqLSDWs-eObQHzh2t1ruoYQ/w400-h300/Riverside11.jpg" width="400" /></a></div><p>It's clearly a difficult site for a footbridge, with the design challenges including the floodplain, the constrained approach directions, and the need to find something for the artist to contribute. I'm quite sure I could have designed something a lot worse. But I didn't admire this bridge: there's too much going on, and the desire for crisp detailing is let down by the compromises made to hold it all together.</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg6pEUNOK10FCAFTh4RWuQfBKN-ZNPW-_gYTkjRBuXOvHonwbAMAEaKYXxHhgSe-HuK8MddQ1O8S5-JQMs6kHO9JQBBKzRg3p9VIWAG7AYBPz7kgmTrRL-HDZTMWgvMHWYhGXWT7o-u20UtS7RMZNb6BMGDKlB1Ol7L301xc4alPeUWdd7eRK1BQs8XIw/s1156/Riverside15.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="867" data-original-width="1156" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg6pEUNOK10FCAFTh4RWuQfBKN-ZNPW-_gYTkjRBuXOvHonwbAMAEaKYXxHhgSe-HuK8MddQ1O8S5-JQMs6kHO9JQBBKzRg3p9VIWAG7AYBPz7kgmTrRL-HDZTMWgvMHWYhGXWT7o-u20UtS7RMZNb6BMGDKlB1Ol7L301xc4alPeUWdd7eRK1BQs8XIw/w400-h300/Riverside15.jpg" width="400" /></a></div><p><b>Further information:</b></p><p></p><ul style="text-align: left;"><li><a href="https://goo.gl/maps/XjhThxjxsctMoAC49">Google maps</a></li><li><a href="https://www.steelconstruction.info/Cambridge_Riverside_Footbridge">Steelconstruction.info</a></li><li><a href="https://structurae.net/en/structures/riverside-bridge">Structurae</a></li><li><a href="https://capturingcambridge.org/barnwell/riverside/riverside-footbridge/">Capturing Cambridge</a></li></ul><p></p>The Happy Pontisthttp://www.blogger.com/profile/15252272118786667592noreply@blogger.com0tag:blogger.com,1999:blog-6470543006314152962.post-13555396967357353622022-05-31T16:22:00.000+01:002022-05-31T16:22:04.729+01:00Garret Hostel Bridge, Cambridge<p>I was in Cambridge earlier this year. Unfortunately, there was no public access to the city's most famous span, the Mathematical Bridge, but I did get the chance to visit two other interesting structures.</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg4c_vM3lHkXTbAV9mcbZumZdzLGAQMYodei_k74HlxXzgcC_6eyzLSYwmHTOAvnOzKLqe8FbC1om74TWr9oOgf1DwMysFWqPQSDzZp6a58h0YKvGR0XBUejT5S4momCdt3zXxL_4yz3KvYbSXS5K7EVHL_PmSskzSOvdfeqZyLsNV2KFiln5UdjI6usA/s1387/Garret1.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1040" data-original-width="1387" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg4c_vM3lHkXTbAV9mcbZumZdzLGAQMYodei_k74HlxXzgcC_6eyzLSYwmHTOAvnOzKLqe8FbC1om74TWr9oOgf1DwMysFWqPQSDzZp6a58h0YKvGR0XBUejT5S4momCdt3zXxL_4yz3KvYbSXS5K7EVHL_PmSskzSOvdfeqZyLsNV2KFiln5UdjI6usA/w400-h300/Garret1.jpg" width="400" /></a></div><p>The Garret Hostel bridge is a modernist classic, completed in 1960 to replace William Chadwell Mylne's cast-iron arch (completed 1837), which had fractured due to settlement. That in turn was only the latest in a long line of bridges built across the River Cam at this site, the first supposedly a timber bridge from the late 15th century. One of the bridges, built in 1769 by James Essex, was named the Mathematical Bridge, similar in appearance to its more famous cousin a short distance along the river.</p><p>The cast iron bridge <a href="https://www.nationaltrustcollections.org.uk/object/206327">can be seen in an illustration</a> in the collection of the National Trust. The "mathematical bridge" of 1769 is <a href="https://www.queens.cam.ac.uk/visiting-the-college/history/college-facts/mathematical-bridge">depicted in an illustration</a> on the Queens' College website.</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg-Qnu8tMm7ufn7MsEuc2OC8h2GL6P5G-gKWBPzw8xH21roooRHE7xnFvKyirsLx7aFypLwR5ihW4O_TZs2f5OqXWQSlr5HJdzAQJg--voo__8l8_Ze4UUrvTrcB5mLIx3VsU3paWwEmrtRFJn5g5W4A7fO1qGkpnF_4Oec-oKvWgLGPZiKZoXI07UOkw/s1200/Garret2.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="900" data-original-width="1200" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg-Qnu8tMm7ufn7MsEuc2OC8h2GL6P5G-gKWBPzw8xH21roooRHE7xnFvKyirsLx7aFypLwR5ihW4O_TZs2f5OqXWQSlr5HJdzAQJg--voo__8l8_Ze4UUrvTrcB5mLIx3VsU3paWwEmrtRFJn5g5W4A7fO1qGkpnF_4Oec-oKvWgLGPZiKZoXI07UOkw/w400-h300/Garret2.jpg" width="400" /></a></div><p>The bridge is Listed Grade II, which is unusual for such a modern structure. It was reportedly designed by Timothy Morgan of the architects Guy Morgan and Partners, who died in the same year that his bridge was opened, according to the bridge's Listing details. According to Atlas Obscura, the architect was intead a Timothy Guy Morgan, an undergraduate at the local school of architecture. The <i>National Trust Book of Bridges</i> instead claims it was Guy Morgan, born 1902. I don't know which of these is correct! The bridge was built by J. L. Kier & Co, who are also cited as the engineer. That bit seems clear.</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgWjih2Tc9xqg6_xY6cTOrwlPprtFPnYhcOoP33b7YxcF_ACKpll_cS1paliwxxPODzwnWCmn548b4NaxNXnJlpgiV9mZnoJnLtC9ZzQ0cil6bgpA_DD2L5nwlAwdTK2McCGbB2pVqU0AGwFBsopOaHPm8eUsRbvygE5wwCWKrqb3OS1uN2xUkMbtExkw/s1387/Garret5.jpg" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="1387" data-original-width="1040" height="200" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgWjih2Tc9xqg6_xY6cTOrwlPprtFPnYhcOoP33b7YxcF_ACKpll_cS1paliwxxPODzwnWCmn548b4NaxNXnJlpgiV9mZnoJnLtC9ZzQ0cil6bgpA_DD2L5nwlAwdTK2McCGbB2pVqU0AGwFBsopOaHPm8eUsRbvygE5wwCWKrqb3OS1uN2xUkMbtExkw/w150-h200/Garret5.jpg" width="150" /></a></div><p>It is an immediately attractive bridge, from almost any angle, with its striking curved concrete underside and central crease-line. Getting up close and seeing how rough the bush-hammered concrete surface is just adds to its charm. The bronze handrails are also a lovely feature.</p><p>Light on the surface of the river reflects in patterns on the underside of the bridge.</p><p>The bridge has the visual form of a very shallow arch, albeit one that is steep to climb and clearly from the days before modern accessibility requirements! However, its true form is hidden within the stone-clad abutments at either end.</p><p>It is a post-tensioned concrete girder bridge, in a shallow portal frame arrangement supported on traditional concrete hinges at its west end, and on some form of metal bearings at the east end. The prestressing cables were tensioned from the west end only, after the concrete was cast, and if you look closely at my photos, you can see the manhole cover which provides access into the hidden jacking chamber.</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEguEqp5jOyKWKiol55kHwjNC344fltY0zG06mXfiqNeTedD3mXeRLIWfOnOGOmhEXZRFYCI5Nyy68mXVbJ-AKpMl0oorS29Lba5z_GsX5Q6jZaXyrgy2JeqjBrbuZjpahWHRgMM4op4zbSS-kh1voigc_dc-xfhCWPou4dd1UNke-rnk2SRUXRHT0sFgw/s4061/GarretAA.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1179" data-original-width="4061" height="116" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEguEqp5jOyKWKiol55kHwjNC344fltY0zG06mXfiqNeTedD3mXeRLIWfOnOGOmhEXZRFYCI5Nyy68mXVbJ-AKpMl0oorS29Lba5z_GsX5Q6jZaXyrgy2JeqjBrbuZjpahWHRgMM4op4zbSS-kh1voigc_dc-xfhCWPou4dd1UNke-rnk2SRUXRHT0sFgw/w400-h116/GarretAA.jpg" width="400" /></a></div><p>It is relatively early for a post-tensioned bridge in the UK, completed 3-4 years after <a href="https://en.wikipedia.org/wiki/Cavendish_Bridge">Cavendish Bridge</a> in Derbyshire, and in the same year as structures such as <a href="https://en.wikipedia.org/wiki/Queen%27s_Bridge,_Perth">Queen's Bridge</a>, Perth, and <a href="https://www.sabre-roads.org.uk/wiki/index.php?title=Bridstow_Bridge">Bridstow Bridge</a>.</p><p>None of this is visually apparent, but fortunately details of the bridge were published in the book <i>Modern British Bridges</i> in 1965, and I've reproduced them here as they are quite informative.</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEicxCkHYGwrRY6rMlYsuttBPpJdRtUhBIT15wTVLBmboW5IWnj-9LnM7IBfX17gYsXGnVVC_LlY7c2hxo2etJHJaCUCyxcRFnLqmV4bTWuwYY0xLu8U6OCXNJ-i0PBsYKN05oIRaTsskxK7rqebt2nIzljcgfsjSdcSjXKR5zgokEAmckI6O2j7bXjyaw/s3092/GarretCC.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2794" data-original-width="3092" height="361" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEicxCkHYGwrRY6rMlYsuttBPpJdRtUhBIT15wTVLBmboW5IWnj-9LnM7IBfX17gYsXGnVVC_LlY7c2hxo2etJHJaCUCyxcRFnLqmV4bTWuwYY0xLu8U6OCXNJ-i0PBsYKN05oIRaTsskxK7rqebt2nIzljcgfsjSdcSjXKR5zgokEAmckI6O2j7bXjyaw/w400-h361/GarretCC.jpg" width="400" /></a></div><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj6yiON-o2KYHCNrH_fqUYdK5oYL1bGplhttpb0wGeHwZP92nhtL80TyWkdAyr8R30aj2fC-yd8ZMC9fIdIByBrjd1J0U_-G7wzGBECd-NeIoJxVeeMiLJLMDmzQTN0hh_FEzk5IK8N89GXPu-OW3yGexWbw1uS-aWC-kObVaTKnTAOIf5U9SQZCSlDPA/s3980/GarretDD.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1213" data-original-width="3980" height="122" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj6yiON-o2KYHCNrH_fqUYdK5oYL1bGplhttpb0wGeHwZP92nhtL80TyWkdAyr8R30aj2fC-yd8ZMC9fIdIByBrjd1J0U_-G7wzGBECd-NeIoJxVeeMiLJLMDmzQTN0hh_FEzk5IK8N89GXPu-OW3yGexWbw1uS-aWC-kObVaTKnTAOIf5U9SQZCSlDPA/w400-h122/GarretDD.jpg" width="400" /></a></div><p></p><p>The drawings show the soffit of the bridge to be parabolic in curvature, and make clear how the cross-section varies in depth from the crown to the supports. The prestressing cables are arranged to resist sagging at the crown, and hogging at the ends.</p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhkTyrWm8FRgroTkDUzO3n93k7MobKiBIJpKi_58fFwLVZHrkDWLtqbo_mSPeNkKMgizXklgz9poagoec3z3Adn3pbOCYfHRaZ4zuuY7dhok-ieDKK3M_FK80xFe1NRfaX0iEbrKgJqgU7Xp6UcPPu67fhCqaRct07YmdCQSGMY-2PwVBANtLUR3tc0SA/s1387/Garret3.jpg" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="1040" data-original-width="1387" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhkTyrWm8FRgroTkDUzO3n93k7MobKiBIJpKi_58fFwLVZHrkDWLtqbo_mSPeNkKMgizXklgz9poagoec3z3Adn3pbOCYfHRaZ4zuuY7dhok-ieDKK3M_FK80xFe1NRfaX0iEbrKgJqgU7Xp6UcPPu67fhCqaRct07YmdCQSGMY-2PwVBANtLUR3tc0SA/w200-h150/Garret3.jpg" width="200" /></a></div>The superstructure is supported on huge reinforced concrete abutments, which sit on raked concrete-filled steel tubular piles.<p></p><p>As is often the case with bridges pushed to the limits of slenderness, the material is simply shifted from one place to another, in this case towards the ends and into the foundations. The span-depth ratio that results is 48:1 (85 ft span vs 1.75 ft depth at crown), which is visually attractive but not <a href="http://www.engineering-timelines.com/scripts/engineeringItem.asp?id=521">especially exotic</a>.</p><p></p><div class="separator" style="clear: both; text-align: right;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjpADGlKghDJeiH3SzMjEL5CfmA51Vrh-BIfBG97zC8WB4uQliaDFTXNmj9AQtVU0wp5k-2oHU-Q23XZCvUYfLRplF3GNeZLeU-or_GBq9yNs_TNqtsg90VwvcdpT7cifvUvsp4X1ssq49RorQqPhQrcfZWl9FVEvixrck0UMlAGSE0bL1uOjiODLf0xQ/s1387/Garret4.jpg" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="1040" data-original-width="1387" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjpADGlKghDJeiH3SzMjEL5CfmA51Vrh-BIfBG97zC8WB4uQliaDFTXNmj9AQtVU0wp5k-2oHU-Q23XZCvUYfLRplF3GNeZLeU-or_GBq9yNs_TNqtsg90VwvcdpT7cifvUvsp4X1ssq49RorQqPhQrcfZWl9FVEvixrck0UMlAGSE0bL1uOjiODLf0xQ/w200-h150/Garret4.jpg" width="200" /></a></div>The drawings make clear that the stone-clad abutments, which look so nice, are essentially fake. Their front faces incline backwards away from the river, perpendicular to the soffit of the bridge to give the visual impression that they resist the thrust of an arch, while in reality doing nothing of the sort.<p></p><p>My view is that if fakery is to be the approach taken in bridge design, this is a great example of how it should be done well. It's a beautiful bridge, and sits nicely amongst its surroundings.</p><p><b>Futher reading:</b></p><p></p><ul style="text-align: left;"><li><a href="https://goo.gl/maps/He54diYRmq5Y281t6">Google maps</a></li><li><a href="https://en.wikipedia.org/wiki/Garret_Hostel_Bridge">Wikipedia</a></li><li><a href="https://britishlistedbuildings.co.uk/101119764-garret-hostel-bridge-between-clare-bridge-and-trinity-bridge-on-the-cam-cambridge-castle-ward#.YgUA_N_P2Uk">British Listed Buildings</a></li><li><a href="https://structurae.net/en/structures/garret-hostel-bridge">Structurae</a></li><li><a href="https://canalplan.uk/place/fh7b">CanalPlanAC</a></li><li><i><a href="https://happypontist.blogspot.com/2010/07/bridges-in-britain-5-modern-british.html">Modern British Bridges</a></i> (Henry and Jerome, 1965)</li><li><i><a href="https://happypontist.blogspot.com/2010/07/bridges-in-britain-2-bridges-of-britain.html">Bridges of Britain</a></i> (de Mare, 1975)</li><li><i><a href="https://happypontist.blogspot.com/2010/07/bridges-in-britain-8-national-trust.html">The National Trust Book of Bridges</a></i> (Richards, 1984)</li><li><i>Civil Engineering Heritage: Eastern & Central England</i> (Labrum, 1994)</li><li><i><a href="https://happypontist.blogspot.com/2019/10/an-encyclopaedia-of-british-bridges-by.html">An Encyclopaedia of British Bridges</a></i> (McFetrich, 2019)</li></ul>The Happy Pontisthttp://www.blogger.com/profile/15252272118786667592noreply@blogger.com5tag:blogger.com,1999:blog-6470543006314152962.post-6161991648477206432022-05-22T14:26:00.000+01:002022-05-22T14:26:26.643+01:00"Thames Bridges" by David C. Ramzan<p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiAS5muKMC07WOBDjwXhqQSCUddV4Y6WVxGUVzGp057TSNh_2U9T20-BXnVjcJF_K4fGnc-Q7JubVa71m5js0SzX3YdL5JLglg31ahu1NLUkzXqGXJ-ASyC-efqA4oJMZg0_Py0LGLd5NsqmpHif3brGQg_b7cousSrBfKVFzy4poChpRvDDQZI2DPqCA/s1000/ramzan%20cover.jpg" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="1000" data-original-width="703" height="200" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiAS5muKMC07WOBDjwXhqQSCUddV4Y6WVxGUVzGp057TSNh_2U9T20-BXnVjcJF_K4fGnc-Q7JubVa71m5js0SzX3YdL5JLglg31ahu1NLUkzXqGXJ-ASyC-efqA4oJMZg0_Py0LGLd5NsqmpHif3brGQg_b7cousSrBfKVFzy4poChpRvDDQZI2DPqCA/w141-h200/ramzan%20cover.jpg" width="141" /></a></div>I do love a bridge book which takes a specific river as its focus, and <i>Thames Bridges</i> (<a href="https://www.amberley-books.com/thames-bridges.html">Amberley Books</a>, 96pp, 2022) is a nice addition to this genre.<p></p><p>As far as the Thames goes, it's a pretty crowded field already, with <i>Crossing London's River</i> (1972), <i>Thames Bridges</i> (1973), <i>Thames Crossings: Bridges, Tunnels and Ferries</i> (1981), <i>Cross River Traffic</i> (2005), <i>Thames Bridges: Then and Now</i> (2006), <i>Thames Bridges: from Dartford to the Source</i> (2007), <i>London's Bridges: Crossing the Royal River</i> (2009), <i>Bridges: XXXIV Crossings of the Thames</i> (2011), <i>Crossing the River</i> (2015), <i>All the Thames Bridges from Source to Dartford</i> (2019), <i>Bridges over the River Thames: From the source to the Sea</i> (2020) .... you get the idea! For collectors of bridge books, is there any need for another one about the bridges of the Thames?</p><p><i>Thames Bridges</i> covers the entirety of the river from its source in Gloucestershire to its estuary, passing under over 200 bridges along the way. The book is extensively illustrated, with photographs on almost every page. For some of the minor bridges, the photograph sufficiently illustrates what they are, and their context. The images are a mixture of old and new, and I especially liked the inclusion of the older photographs - so much of the narrative relates to the history of the land, the river, and its crossings, that these help bring that tale to life.</p><p>Outside the heart of London, this is the river of Clark's Marlow Suspension Bridge, Brunel's Maidenhead Railway Bridge, the old and new bridges at Runnymede (Lutyens and Arup), Hampton Court Bridge, and of course the mighty Queen Elizabeth II Bridge. It is undeniably an important river, spanned by many undeniably important bridges.</p><p><i>Thames Bridges</i> rarely wastes too many words on any span, and this is definitely not a book that can be considered an in-depth gazetteer. However, it's concisely written, with enough on each structure to grasp key facts, understand their significance, and relate them to the wider history of the area. There is plenty of history, and the book touches on Mesolithic settlements, Roman construction, as well as more modern attempts to reshape the landscape.</p><p>I particularly enjoyed the book's sense of pace, which remains unhurried throughout. I think it is best read in order, starting with relatively humble spans and a river that is little more than a stream, and seeing the images of bridges growing very slowly steadily in scale, with tales of increasingly impressive engineering achievement as the book draws you steadily downstream.</p><p>For those with a general interest in the Thames, and its history, I can certainly recommend <i>Thames Bridges</i>. It is an accessible, well-written survey. I think that those with greater knowledge of the Thames and its bridges should also enjoy it: it left me with a little bit of a desire to hunt out some maps of the Thames path, as this book would make an excellent companion to a river tour!</p><p><b>Postscript</b></p><p>For some other examples of books in the bridges-by-river genre, here are some that I have reviewed previously:</p><p></p><ul style="text-align: left;"><li><i><a href="https://happypontist.blogspot.com/2020/08/bridging-tweed-by-jim-lyon.html">Bridging the Tweed</a></i> (2020)</li><li><i><a href="https://happypontist.blogspot.com/2018/03/danube-bridges-by-peter-gyukics.html">Danube-bridges</a></i> (2018)</li><li><i><a href="https://happypontist.blogspot.com/2017/02/bridges-of-dublin-by-annette-black.html">Bridges of Dublin</a></i> (2017)</li><li><i><a href="https://happypontist.blogspot.com/2017/01/bridges-of-paris-by-michael-saint-james.html">Bridges of Paris</a></i> (2017)</li><li><i><a href="https://happypontist.blogspot.com/2017/01/the-glow-of-paris-bridges-of-paris-at.html">The Glow of Paris</a></i> (2017)</li><li><i><a href="https://happypontist.blogspot.com/2012/01/river-axe-crossings-from-mouth-to.html">River Axe Crossings: from Mouth to Source</a></i> (2012)</li></ul><p></p>The Happy Pontisthttp://www.blogger.com/profile/15252272118786667592noreply@blogger.com0tag:blogger.com,1999:blog-6470543006314152962.post-29630695019427675922022-05-11T20:00:00.001+01:002022-05-11T20:00:00.179+01:00"An Encyclopaedia of World Bridges" by David McFetrich<p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjYhdC8Nt-jChOa2giaoWwsWZ_-tRPZr0R-IgWJVdEUfF_Wf3Oyig1sEjGqZ1oiuiPhozQ1v44la2A835lwi1h8992EpTiXg5RrAei3_rFetVpMBKFHCTe-vHeeRw8aY4x5Fj6CIY5yq3ZOv8hU2PqkDqlv8acIystIelR1tcOANcfRzicGp_IEmXun9Q/s531/Cover.jpg" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="531" data-original-width="404" height="200" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjYhdC8Nt-jChOa2giaoWwsWZ_-tRPZr0R-IgWJVdEUfF_Wf3Oyig1sEjGqZ1oiuiPhozQ1v44la2A835lwi1h8992EpTiXg5RrAei3_rFetVpMBKFHCTe-vHeeRw8aY4x5Fj6CIY5yq3ZOv8hU2PqkDqlv8acIystIelR1tcOANcfRzicGp_IEmXun9Q/w152-h200/Cover.jpg" width="152" /></a></div>This new book is the follow-up to the author's previous <i><a href="https://happypontist.blogspot.com/2019/10/an-encyclopaedia-of-british-bridges-by.html">Encyclopaedia of British Bridges</a></i>, which I reviewed in 2019 (and <a href="https://happypontist.blogspot.com/2010/10/encyclopaedia-of-britains-bridges.html">its predecessor</a>, back in 2010).<p></p><p>It lists and briefly describes over 1200 bridges in over 170 different countries, and there truly is nothing else quite like it.</p><p><i>An Encyclopaedia of World Bridges</i> (<a href="https://www.pen-and-sword.co.uk/An-Encyclopaedia-of-World-Bridges-Hardback/p/20379">Pen and Sword Books</a>, 352pp, 2022 - also available in ePub and Kindle format) starts with an introduction and useful glossary of terms, and finishes with 90 pages of Appendices (of which, more later). However the core of the book is an A-Z of bridges around the world: well-known, not-so-well-known, significant, and curious.</p><p>It's smaller in size, and shorter than its predecessor (<i>British Bridges</i> had 444 pages covering over 1600 bridges) but it's still a mammoth undertaking. I've pictured it as part of its family for scale.</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj-3HJVgKC0DlySGHfY6PRJybuQdrWDSmRWJzDtqwcKMldkNvipdZrp3fMAtYdsdjFaiHRf_6kBYMgutpawDE8W_7O-rU2vb-Ehe1rIau623FKQtDzjik-uGUVwcwVGT-QuuRUemZ2QMDonRe8_EBgHpeHoRqCINnbX7AAH3RpCdwU_9NUjftAYs_F1rw/s1156/McFetrich1.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="867" data-original-width="1156" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj-3HJVgKC0DlySGHfY6PRJybuQdrWDSmRWJzDtqwcKMldkNvipdZrp3fMAtYdsdjFaiHRf_6kBYMgutpawDE8W_7O-rU2vb-Ehe1rIau623FKQtDzjik-uGUVwcwVGT-QuuRUemZ2QMDonRe8_EBgHpeHoRqCINnbX7AAH3RpCdwU_9NUjftAYs_F1rw/w400-h300/McFetrich1.jpg" width="400" /></a></div><p>The entry for each bridge has a paragraph giving key details, and every page in the main section is illustrated with colour photos, although less than half of the structures have an accompanying image. There is sufficient information in almost every case to answer key questions, and the internet will beckon if an entry particularly piques anyone's curiosity.</p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgYe4ZNmNsxrMohAvo7ONT9pRMDwD5pPQxEcqZ1Fh3iqzOYkyc3dYJNOaQuv7-h0qsKCaTlgSRPUBSTmpb2d7mrd3TLRbjgk91-ztjwllRlnSz5TNoefelXUceds4no1aAtvM4WuziVDZkffggWFkLUr3WxVxamVKLcu36Jq1273Q-afteCxNmjFsFCuw/s1156/McFetrich2.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="867" data-original-width="1156" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgYe4ZNmNsxrMohAvo7ONT9pRMDwD5pPQxEcqZ1Fh3iqzOYkyc3dYJNOaQuv7-h0qsKCaTlgSRPUBSTmpb2d7mrd3TLRbjgk91-ztjwllRlnSz5TNoefelXUceds4no1aAtvM4WuziVDZkffggWFkLUr3WxVxamVKLcu36Jq1273Q-afteCxNmjFsFCuw/w200-h150/McFetrich2.jpg" width="200" /></a></div>Nitpicking Pontists can go through the book looking for surprising omissions (and there are plenty - I will leave this as an exercise for readers to address through this blog's comments function, if they wish!) However, I found I discovered far more that was unknown to me than I felt was missing. There are bridges of every conceivable age, shape and size. The sheer variety gives the lie to the traditional idea that there are really only four types of bridge (beam, arch, suspension, and stayed), with plenty of bridges that defy these simple categorisations.<p></p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiu_SRDVVBtw2e8EW4sQ3vc_CN3NNgJZ48wtr2SYASgBcSXmA2w7ecdIompP70U0lkexF2lQE8vHLc55BT_wIcXiArGU7YPkFLpP2__An8zkhE8KG8K1DNwVa6la_mF5CO7Yw-SyIixx1FS1t9ad51pk6L8S9uWlyVmLBPEnoetcdgwicZ0kwGC3CABkg/s1156/McFetrich3.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="867" data-original-width="1156" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiu_SRDVVBtw2e8EW4sQ3vc_CN3NNgJZ48wtr2SYASgBcSXmA2w7ecdIompP70U0lkexF2lQE8vHLc55BT_wIcXiArGU7YPkFLpP2__An8zkhE8KG8K1DNwVa6la_mF5CO7Yw-SyIixx1FS1t9ad51pk6L8S9uWlyVmLBPEnoetcdgwicZ0kwGC3CABkg/w200-h150/McFetrich3.jpg" width="200" /></a></div>The Appendices include helpful indexes of bridges by country and according to key participants in construction, obstacle spanned etc. There is an excellent bibliography with over 325 entries (although sadly for true enthusiasts, the sources of information for each bridge are not linked to the bibiliography, as was the case in the <i>British Bridges</i> volume).<p></p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjnB814ngZevEW0d07s0lX_kGOJ3VBGB_K6hyycmNC1ckJQa8yz7ff6z5bLtPsH6Bo_OTOblsDeVotefdmMsADW8m2C0YXwcThyJYNRWvCD7nPT-F6WO-gzC5PQHF1XmaEBXqQdzWGDQ9d0VAKNhJ4VwA3k7OuK-VDmW7YCVLnvwlO0NHAhwuGCyb3Q5w/s1156/McFetrich4.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="867" data-original-width="1156" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjnB814ngZevEW0d07s0lX_kGOJ3VBGB_K6hyycmNC1ckJQa8yz7ff6z5bLtPsH6Bo_OTOblsDeVotefdmMsADW8m2C0YXwcThyJYNRWvCD7nPT-F6WO-gzC5PQHF1XmaEBXqQdzWGDQ9d0VAKNhJ4VwA3k7OuK-VDmW7YCVLnvwlO0NHAhwuGCyb3Q5w/w200-h150/McFetrich4.jpg" width="200" /></a></div>The most interesting Appendix offers no less than 76 lists of bridges by various categories, some obvious, some much less so. Here you will find lists of Inhabited Bridges, Highest Bridges, Monorail Bridges, Chain Suspension Bridges etc. But also the less obvious Copy Bridges, Bridges Stranded by Changes in the Course of Rivers, Natural Fibre Bridges, Pilgrim Routes over Bridges and many more. I found this a particularly intriguing section of the book, giving the reader a number of ways to engage with the topic other than simply flipping through from A to Z.<p></p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgIBFDNrUBvHObu10byF0vItkGQc6pumhI9rlBmo3ZWKglnripYYgxJrNzV-wIRUllEzLwnxpXpx-mO5DGOBBhHypJ_vfMZAxn1yGi653Ow8aLmvtBCdhnGTijRvtjApDfy8EuwgDiH4fw-vo6IB-UmVd8o_UprDVKGTeBgdjYEp6WeZ66-hi7e65FZXA/s1156/McFetrich5.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="867" data-original-width="1156" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgIBFDNrUBvHObu10byF0vItkGQc6pumhI9rlBmo3ZWKglnripYYgxJrNzV-wIRUllEzLwnxpXpx-mO5DGOBBhHypJ_vfMZAxn1yGi653Ow8aLmvtBCdhnGTijRvtjApDfy8EuwgDiH4fw-vo6IB-UmVd8o_UprDVKGTeBgdjYEp6WeZ66-hi7e65FZXA/w200-h150/McFetrich5.jpg" width="200" /></a></div>I can heartily recommend the book to anyone with an interest in the history or architecture of bridges. For the world tourist, it could easily have been titled <i>1001 Bridges to See Before You Die (and a few more)</i>, in the vein of the popular bucket-list books aimed at people who lack the time or opportunity to travel.<p></p><p>I must confess I have not actually read every page yet: but it will be sitting on my desk for the foreseeable future, a book to dip into repeatedly.</p>The Happy Pontisthttp://www.blogger.com/profile/15252272118786667592noreply@blogger.com0tag:blogger.com,1999:blog-6470543006314152962.post-79186728329128729432022-05-09T20:00:00.001+01:002022-05-09T20:00:00.183+01:00Welsh Bridges: 23. Dernol Footbridge, River Wye<p>This was the third of three bridges that I tried to visit on the River Wye in Powys in August this year.</p><p>The first was barely a ghost, and the second a literal washout. Would it be third time lucky?</p><p>I parked up in a layby on the A470, north-east of the bridge, and followed a public right of way through the fields and downhill towards the site of the bridge.</p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEgkfv6zMiRgKpftrKhw5oCaQ_S0YiHtIeez-HMGXLNF138IL0Lf2LoDp7cSwn83Lj9g90lbBHz8y1KMHbez4GJF97XiEq7nyctlI1xb3QDffwI6S5YBqAmddMf8r_nvxBE88wAZdJHe2N2c--4CB2t3PZbcaOb8mBrjWhzUfKZsH56izZo_lrTKpprkng=s1210" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1210" data-original-width="907" height="400" src="https://blogger.googleusercontent.com/img/a/AVvXsEgkfv6zMiRgKpftrKhw5oCaQ_S0YiHtIeez-HMGXLNF138IL0Lf2LoDp7cSwn83Lj9g90lbBHz8y1KMHbez4GJF97XiEq7nyctlI1xb3QDffwI6S5YBqAmddMf8r_nvxBE88wAZdJHe2N2c--4CB2t3PZbcaOb8mBrjWhzUfKZsH56izZo_lrTKpprkng=w300-h400" width="300" /></a></div><p></p><p>A bridge! A palpable bridge!</p><p>Alan Crow's book <i>Bridges on the River Wye</i> indicates that a suspension footbridge was built here in 1975 by the Newbridge-on-Wye firm N.R. Hope. From the description, it is the same bridge that can be seen today, except that all or much of the fabric may have been renewed. Powys County Council tell me that <a href="https://www.brecon-radnor.co.uk/article.cfm?id=106286&headline=Powys%20council%E2%80%99s%20team%20puts%20in%20the%20hours%20improving%20our%20countryside&sectionIs=news&searchyear=2018 ">the bridge was "refurbished" in 2018</a>.</p><p>The bridge is of essentially the same design as the now-destroyed Cwmcoch footbridge, constructed by the same builder in 1967.</p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEhRRQgeVVv0z8zig0QPQdgsHlX1CffEss19GFJvY-7ALxQ4R39ruGbElzWzL97cY11D7_27ONHSrMdMfXvXMLky0TljvazDsJM-yUMoOABmZ0YEZP7BW7i8-aaWfGk1UmEhG0WRemuxXAIvHXpwblZHBnbmp_uLCDVNYwdXxGd5G0wqkC6Qrowq_eZGeA=s1210" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1210" data-original-width="907" height="400" src="https://blogger.googleusercontent.com/img/a/AVvXsEhRRQgeVVv0z8zig0QPQdgsHlX1CffEss19GFJvY-7ALxQ4R39ruGbElzWzL97cY11D7_27ONHSrMdMfXvXMLky0TljvazDsJM-yUMoOABmZ0YEZP7BW7i8-aaWfGk1UmEhG0WRemuxXAIvHXpwblZHBnbmp_uLCDVNYwdXxGd5G0wqkC6Qrowq_eZGeA=w300-h400" width="300" /></a></div><p></p><p>Timber towers sit on concrete footings, and support a steel tube or roller over which the main cables pass. Additional stay cables are attached to the rear face of the towers.</p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEisxLHts0-qBTzAAcuLIuXm-oeXQwbp-1664n6ZyvTmEM5Ns3skqdJHBySceNOy9VebbUgFQj0K0CxzFP7UMeUtEnoDT7e0TpbggqB7A0p9MYy_7-HWeJvIS--MEf7y4BNHGCd-uoBC37xXZMZ9KpTT2k4UlsoD7MRJdgdkZyu-sIvjlq5kVyS3iqVtrw=s1210" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1210" data-original-width="907" height="400" src="https://blogger.googleusercontent.com/img/a/AVvXsEisxLHts0-qBTzAAcuLIuXm-oeXQwbp-1664n6ZyvTmEM5Ns3skqdJHBySceNOy9VebbUgFQj0K0CxzFP7UMeUtEnoDT7e0TpbggqB7A0p9MYy_7-HWeJvIS--MEf7y4BNHGCd-uoBC37xXZMZ9KpTT2k4UlsoD7MRJdgdkZyu-sIvjlq5kVyS3iqVtrw=w300-h400" width="300" /></a></div><p></p><p></p><p>The main cables are anchored to steel cantilever beams at each end of the bridge. Three parapet wires on each side of the bridge are also tensioned against these cantilevers, and the tower stay cables are spliced into the lower of these parapet wires.</p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEjDKUsQDJcRRaSVx2QEOOFnlDivZmhwE4Q3XLnC89pmrzVOrJ7pHZuIh-vOoRmiyU9aH0YkqlTSgwV__FXrW2u9RJk44RlNwcKTM8plcwXOBQNvszUCiYC5Sy2Vi3_IIOMD4-fCjSjpEv0WIHu6tAUF5V5xDSkSKVVQmoX7rwadwMecLNAq9aLuZT2y_g=s1210" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1210" data-original-width="907" height="400" src="https://blogger.googleusercontent.com/img/a/AVvXsEjDKUsQDJcRRaSVx2QEOOFnlDivZmhwE4Q3XLnC89pmrzVOrJ7pHZuIh-vOoRmiyU9aH0YkqlTSgwV__FXrW2u9RJk44RlNwcKTM8plcwXOBQNvszUCiYC5Sy2Vi3_IIOMD4-fCjSjpEv0WIHu6tAUF5V5xDSkSKVVQmoX7rwadwMecLNAq9aLuZT2y_g=w300-h400" width="300" /></a></div><p></p><p>The bridge floor comprises three timber planks running longitudinally, sitting on transverse timber members. Every third cross-member also provides the support for braced parapet posts.</p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEjohZG-lr5D3iRLoxmplErEkb3g1DPCZ3XVmjqz9fmV6pEqw1gM6s6mWd0dp7NrA2IFQ8B3-Spbt0LoBiDuW92Cs20uNxDzqmqpZFaD7u_WNB8Ea-gt08dYaVZNcJE70ctTZwFAvDiW1iYcoGoG64F4RacfjdqJGIE023SDMTQohDh8gNvCNYj2Z6zXEw=s1210" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1210" data-original-width="907" height="400" src="https://blogger.googleusercontent.com/img/a/AVvXsEjohZG-lr5D3iRLoxmplErEkb3g1DPCZ3XVmjqz9fmV6pEqw1gM6s6mWd0dp7NrA2IFQ8B3-Spbt0LoBiDuW92Cs20uNxDzqmqpZFaD7u_WNB8Ea-gt08dYaVZNcJE70ctTZwFAvDiW1iYcoGoG64F4RacfjdqJGIE023SDMTQohDh8gNvCNYj2Z6zXEw=w300-h400" width="300" /></a></div><p></p><p>Below the bridge decking, six parallel wires run longitudinally, and these provide substantial support to the deck along most of its length, as there are no vertical hangers as you would expect on a conventional suspension bridge. The deck wires are anchored to steel cross-members attached to the main anchor stanchions.</p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEiOIasRdx3s-brzMXp9-f4NqFRz4-9Fefxs4fClO0_EJMFd6cgDoPN5CyI_NZF97gPmHj_e5LgGnb7rUckm0JWkVlbPzaLYJjnw9ExlDoCTXUTqOvF9rlydRvwmnb7EewHtUYwic3X33O1wHQv07EOI2bk7uAFlP23mQ3wV4nh70pto8dvw7lF2IyVetQ=s1210" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="907" data-original-width="1210" height="300" src="https://blogger.googleusercontent.com/img/a/AVvXsEiOIasRdx3s-brzMXp9-f4NqFRz4-9Fefxs4fClO0_EJMFd6cgDoPN5CyI_NZF97gPmHj_e5LgGnb7rUckm0JWkVlbPzaLYJjnw9ExlDoCTXUTqOvF9rlydRvwmnb7EewHtUYwic3X33O1wHQv07EOI2bk7uAFlP23mQ3wV4nh70pto8dvw7lF2IyVetQ=w400-h300" width="400" /></a></div><p></p><p>The main suspension cables only directly support the middle part of the deck. The two cables pass below grooved longitudinal timber members on each edge of the bridge.</p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEgGMgAkXbCT2I4oeOVSmEhuIPBo4sS_UbYmzCdYI-FOCdzfEyTZjcGV7bfvJCOkehez-Kag_8ijKa5Hi8movcraulsvXH6PCXKMvqR24-zyisHWS3Bd_lALLQUOognWOMewLgy_dLHdMnvK8XD_R_0m8sxZR-J23S2eOXdA9KqVnxqyNkG6y5t3RgHiuA=s1210" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="907" data-original-width="1210" height="300" src="https://blogger.googleusercontent.com/img/a/AVvXsEgGMgAkXbCT2I4oeOVSmEhuIPBo4sS_UbYmzCdYI-FOCdzfEyTZjcGV7bfvJCOkehez-Kag_8ijKa5Hi8movcraulsvXH6PCXKMvqR24-zyisHWS3Bd_lALLQUOognWOMewLgy_dLHdMnvK8XD_R_0m8sxZR-J23S2eOXdA9KqVnxqyNkG6y5t3RgHiuA=w400-h300" width="400" /></a></div><p></p><p>In the absence of the under-deck wires, this would be quite an unstable arrangement, as the central portion would "rock" longitudinally under load. The deck wires are therefore essential both to prevent that rocking, and to support the deck between the points where the main cables connect.</p><p>I've included a few more photographs to illustrate both the details and the setting of this attractive, economical bridge, and a video to show how much it moves under a single person load.</p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEjsIJ1dfFlkAsm4K9B5iNrlQcKoaQ_N8bUt-PQnjhmBDVhJf_r0sw-Ak2_ven_31VY9-L-nW-oRbmIhDcrPMepHszWFiX0I0yjH7oYm90lxyEEmf2YKIDJ7-g_3ZMVUtxrgQKGtIorVuzlATN9jAC-TsfpgZznUDdVnHJt1_2G3pKL0Z4UxOGxir6ESaw=s1210" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="907" data-original-width="1210" height="300" src="https://blogger.googleusercontent.com/img/a/AVvXsEjsIJ1dfFlkAsm4K9B5iNrlQcKoaQ_N8bUt-PQnjhmBDVhJf_r0sw-Ak2_ven_31VY9-L-nW-oRbmIhDcrPMepHszWFiX0I0yjH7oYm90lxyEEmf2YKIDJ7-g_3ZMVUtxrgQKGtIorVuzlATN9jAC-TsfpgZznUDdVnHJt1_2G3pKL0Z4UxOGxir6ESaw=w400-h300" width="400" /></a></div><p></p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEjCAy5RACYi-bRHUDPJyXNnf-6MeknfeOCA05dINzSU0Myl7HIlM1_g8NNIvT0-R-sVfDQv9m1wuG02S5QlK8hx5A2ehWg0ERo2x0umZhaPNzzVp86YBxmDqruOgyYe8pO3Eb1EZ8PDIJOqL9LYlvSula9yY3-BD5z7h3N1SeOAZ4WksP-AD3U1S1r2IQ=s1210" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="907" data-original-width="1210" height="300" src="https://blogger.googleusercontent.com/img/a/AVvXsEjCAy5RACYi-bRHUDPJyXNnf-6MeknfeOCA05dINzSU0Myl7HIlM1_g8NNIvT0-R-sVfDQv9m1wuG02S5QlK8hx5A2ehWg0ERo2x0umZhaPNzzVp86YBxmDqruOgyYe8pO3Eb1EZ8PDIJOqL9LYlvSula9yY3-BD5z7h3N1SeOAZ4WksP-AD3U1S1r2IQ=w400-h300" width="400" /></a></div><p></p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEj4SRZgM-x-bOvEuxrf4cRwi_cP_uXaV5lAD-cRRBj3VKQpY0vDhME4gkDevhm0k37Ka6yLu1DauMmtio0KE_urMuJ820NwGmf72CtnEU8WAIZX2uQu4dtHyJmcm9wsIJp3691QehAwkqcaQ2cBdOOe_VWPf7dNrzWszhsEst3BhvKxdwT5RukNOJIY7Q=s1210" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1210" data-original-width="907" height="400" src="https://blogger.googleusercontent.com/img/a/AVvXsEj4SRZgM-x-bOvEuxrf4cRwi_cP_uXaV5lAD-cRRBj3VKQpY0vDhME4gkDevhm0k37Ka6yLu1DauMmtio0KE_urMuJ820NwGmf72CtnEU8WAIZX2uQu4dtHyJmcm9wsIJp3691QehAwkqcaQ2cBdOOe_VWPf7dNrzWszhsEst3BhvKxdwT5RukNOJIY7Q=w300-h400" width="300" /></a></div><p></p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEgPdoYulxZFeDQgh7BikllupJYcyzLQXTIh9xmCxm9jdWWmDY9DkPzpGTV-Vf7EptJlZ4AGrzBTJpZ6nRdYtxxg1rDwTqRMWWT3QrA3kSG2hy6MrijIpc9J5fIJEx5KnZ5ppNLnXZ-daYmg8ed-LXl5e6Dh6FiVZpIu5JGcEVAjNKh4lKXs7OEXzhS0Cw=s1210" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1210" data-original-width="907" height="400" src="https://blogger.googleusercontent.com/img/a/AVvXsEgPdoYulxZFeDQgh7BikllupJYcyzLQXTIh9xmCxm9jdWWmDY9DkPzpGTV-Vf7EptJlZ4AGrzBTJpZ6nRdYtxxg1rDwTqRMWWT3QrA3kSG2hy6MrijIpc9J5fIJEx5KnZ5ppNLnXZ-daYmg8ed-LXl5e6Dh6FiVZpIu5JGcEVAjNKh4lKXs7OEXzhS0Cw=w300-h400" width="300" /></a></div><p></p><div class="separator" style="clear: both; text-align: center;"><iframe allowfullscreen="" class="BLOG_video_class" height="266" src="https://www.youtube.com/embed/gw4a6CTu4FQ" width="320" youtube-src-id="gw4a6CTu4FQ"></iframe></div><p><b>Further information:</b></p><p></p><ul style="text-align: left;"><li><a href="https://www.google.co.uk/maps/place/52%C2%B021'42.6%22N+3%C2%B035'28.1%22W/@52.3618358,-3.5923332,301m/data=!3m2!1e3!4b1!4m6!3m5!1s0x0:0x6dbfde9ed01bf755!7e2!8m2!3d52.3618341!4d-3.5911395">Google maps</a></li><li><i><a href="https://www.blogger.com/blog/post/edit/6470543006314152962/5983849061988678447#">Bridges on the River Wye</a></i>, Alan Crow, 1995</li></ul><p></p>The Happy Pontisthttp://www.blogger.com/profile/15252272118786667592noreply@blogger.com0tag:blogger.com,1999:blog-6470543006314152962.post-59838490619886784472022-05-08T20:00:00.001+01:002022-05-08T20:00:00.183+01:00Welsh Bridges: 22. Cwmcoch Footbrige, River Wye<p>This is the next crossing of the River Wye upstream from the Cwmbach Footbridge discussed in my previous post.</p><p>It was built in 1967 by N.R. Hope of Newbridge-on-Wye, a "swing" suspension bridge of total length around 53m. A wooden beam bridge had previously spanned the river here, before being destroyed in the 1960 floods.</p><p>If you were unaware that this bridge existed, you would never look for it. I parked in the entrance to a farm track (although I can't recommend this) on the A470, and walked downhill. There is also space to park on the minor road on the opposite side of the river.</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEgHz6vVqWDCSHwHQnBDwwNjx8eITXDIPBWfI27ZT8XRkZHve65uSKShd_pluMClO2sWPN76xR4xF7wpnNNryr-n_bHG2q3TKUMba3E0KXtaXb-4F9CxA1WKFQ_9xk5xTHt_g5p8IAMMXQsSHuQBTwuOjJHnCeLK24eGiDsb6hX_ITfdljT8sHl30xI1Kw=s1008" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1008" data-original-width="756" height="400" src="https://blogger.googleusercontent.com/img/a/AVvXsEgHz6vVqWDCSHwHQnBDwwNjx8eITXDIPBWfI27ZT8XRkZHve65uSKShd_pluMClO2sWPN76xR4xF7wpnNNryr-n_bHG2q3TKUMba3E0KXtaXb-4F9CxA1WKFQ_9xk5xTHt_g5p8IAMMXQsSHuQBTwuOjJHnCeLK24eGiDsb6hX_ITfdljT8sHl30xI1Kw=w300-h400" width="300" /></a></div><p style="clear: both; text-align: justify;"><span style="text-align: left;">And indeed ... there was no bridge to find. At least, not one that you can still cross.</span></p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEhEonUhv8kRgQkWBgoUmza1jJwvp9yr3wjoQlyu_nr__s17BQZq6LyAbF__aMvKP2t5AKRcpAPi6wiauntXe2uTLskqDl_k5UdDD1l4NnLR9uQ50lQYyJXdKSBv4avGl-giyK-rJtIXH5iiVs1b5gi843dgpc6G36M6ysQoXpsHQMBJJk8FXNGTE25rpA=s1210" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="907" data-original-width="1210" height="300" src="https://blogger.googleusercontent.com/img/a/AVvXsEhEonUhv8kRgQkWBgoUmza1jJwvp9yr3wjoQlyu_nr__s17BQZq6LyAbF__aMvKP2t5AKRcpAPi6wiauntXe2uTLskqDl_k5UdDD1l4NnLR9uQ50lQYyJXdKSBv4avGl-giyK-rJtIXH5iiVs1b5gi843dgpc6G36M6ysQoXpsHQMBJJk8FXNGTE25rpA=w400-h300" width="400" /></a></div><p></p><p>Powys County Council have no record of the bridge, suggesting this may have been a private bridge as there is no recorded public right of way.</p><p>However, Alan Crow's book <i>Bridges on the River Wye</i>, indicates that the bridge was built by the council, after an application to the Ministry of Agriculture and Fisheries for a grant to build a vehicular bridge was rejected.</p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEinQsnBR7_J0d0nojxOq64bFtOSV0VDzmmzJn0_dnJFnnFm8bIrynkBv1eNrVrvoAc9UisPUKY3vphTRr5AJkxEt_V8V_48v83QqLefEXlRsUFEMQzn_Z2a-JJebDdQCnm5uPUso6aiGca6nkf1tmIjm2msIb5nnWMwH_o9unbNqIwUsp7AO8vFb1urIg=s1210" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="907" data-original-width="1210" height="300" src="https://blogger.googleusercontent.com/img/a/AVvXsEinQsnBR7_J0d0nojxOq64bFtOSV0VDzmmzJn0_dnJFnnFm8bIrynkBv1eNrVrvoAc9UisPUKY3vphTRr5AJkxEt_V8V_48v83QqLefEXlRsUFEMQzn_Z2a-JJebDdQCnm5uPUso6aiGca6nkf1tmIjm2msIb5nnWMwH_o9unbNqIwUsp7AO8vFb1urIg=w400-h300" width="400" /></a></div><p></p><p>Considering that the remains of the bridge are still visible, attached to the western abutment, I guess that this bridge may have been destroyed in the floods of February 2020.</p><p>Peering closely at the debris of the bridge, it can be seen that there was a timber walkway, three planks wide, supported on timber cross-members. Below these are a set of six parallel wires, an arrangement similar to the <a href="https://happypontist.blogspot.com/2012/10/scottish-bridges-54-footbridge-at.html">Invermark Footbridge</a> in Scotland. The remains of suspension towers and cables are also just about visible.</p><p>I have included a picture of this bridge from Crow's book, to show it as it once was.</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEiOlUqXKR5QYpiqmhqGkXp1yL9kwPVIecq9ULHdUookJif_CRohlRjgJCOgezcgNN1yj1eIVrM6nv95MwlGfnI_gle72h48YCuSP3kxjSL8CMnBxQdxV5ZnC7reKGAXfdLTW65plrS21PDRb4u7-66XhiV0bbblvZjfUF1HQHhMzjD84403IA_7-NVf-g=s2048" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2048" data-original-width="1394" height="400" src="https://blogger.googleusercontent.com/img/a/AVvXsEiOlUqXKR5QYpiqmhqGkXp1yL9kwPVIecq9ULHdUookJif_CRohlRjgJCOgezcgNN1yj1eIVrM6nv95MwlGfnI_gle72h48YCuSP3kxjSL8CMnBxQdxV5ZnC7reKGAXfdLTW65plrS21PDRb4u7-66XhiV0bbblvZjfUF1HQHhMzjD84403IA_7-NVf-g=w273-h400" width="273" /></a></div><p><b>Further information:</b></p><p></p><ul style="text-align: left;"><li><a href="https://www.google.co.uk/maps/place/52%C2%B019'23.1%22N+3%C2%B032'39.9%22W/@52.3230837,-3.5455766,294m/data=!3m2!1e3!4b1!4m6!3m5!1s0x0:0x753a849b12907c6d!7e2!8m2!3d52.3230822!4d-3.5444093">Google maps</a></li><li><i><a href="https://amzn.to/3DjQQVD">Bridges on the River Wye</a></i>, Alan Crow, 1995</li></ul><p></p>The Happy Pontisthttp://www.blogger.com/profile/15252272118786667592noreply@blogger.com1tag:blogger.com,1999:blog-6470543006314152962.post-56797206090302706572022-05-07T10:23:00.001+01:002022-05-07T10:23:47.955+01:00Welsh Bridges: 21. Cwmbach Footbridge, River Wye<p>Back in August 2021 (yes, time has been moving slowly here at Pontist Towers), I had the chance to look for three interesting footbridges along the River Wye in Powys. I had discovered all three in Alan Crow's excellent 1995 book <i>Bridges on the River Wye.</i></p><p>Unfortunately, my search was less successful than I had hoped!</p><p>To reach the first of these spans, I parked in a layby on the A470 (see Google Maps link below), then crossed the road and headed downhill towards the river. Slightly further south, a public right of way is marked on the OS map, but no bridge is shown.</p><p>Crow's book records that a "swing" bridge was built here in 1962, to replace a structure that had been destroyed by a flood in 1960. This is the term "swing" bridge in its colloquial sense, referring to a slightly unstable suspension bridge. It was demolished in 1991 on safety grounds, and a new bridge was installed in August 1994 by Tysons plc, of Liverpool.</p><p>This was the bridge I had come to see: an arched beam bridge constructed in laminated timber, described by Crow as <i>"one of the most attractive small bridges on the River Wye"</i>.</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEjRkN-lXloIxa4sE8PlVElHtZ_pQT4w927v7oWpBWH-y0ykh8kOI8PWcahIlKuKnknIw1wiVARbOfkhpiV08hGxrN-Uat5aeWVtO_6o_wV1iGeK3188SujG18BNm3v9-V6STmbXhUlz93bB7TD3H5TY5Brkl_EWSRGI5sRNF_LuQ1RNBQOiDQpP6qcHag=s1387" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="528" data-original-width="1387" height="153" src="https://blogger.googleusercontent.com/img/a/AVvXsEjRkN-lXloIxa4sE8PlVElHtZ_pQT4w927v7oWpBWH-y0ykh8kOI8PWcahIlKuKnknIw1wiVARbOfkhpiV08hGxrN-Uat5aeWVtO_6o_wV1iGeK3188SujG18BNm3v9-V6STmbXhUlz93bB7TD3H5TY5Brkl_EWSRGI5sRNF_LuQ1RNBQOiDQpP6qcHag=w400-h153" width="400" /></a></div><p>Sadly, there was no bridge to be found. If you look very closely at my main photo, perhaps you can spot the abutments.</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEjooUZOwo9WRcgbdxQaxF7ibotEluzxleUlxNthlMR2f3upQN36Wp6bg2ZJwGBDi7q9cAWYoxHFHgu4AcWl2C45gWd-So9MiysZx2pBTioBE9TFevA6wXR_WrnB0tfJ47He_kUpTbcvr5e6zuMPrXvs6sEzgvcfFfPWVX84kNSAkY6XUD7LA9rVpVVNZw=s1210" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1210" data-original-width="907" height="400" src="https://blogger.googleusercontent.com/img/a/AVvXsEjooUZOwo9WRcgbdxQaxF7ibotEluzxleUlxNthlMR2f3upQN36Wp6bg2ZJwGBDi7q9cAWYoxHFHgu4AcWl2C45gWd-So9MiysZx2pBTioBE9TFevA6wXR_WrnB0tfJ47He_kUpTbcvr5e6zuMPrXvs6sEzgvcfFfPWVX84kNSAkY6XUD7LA9rVpVVNZw=w300-h400" width="300" /></a></div><p>The concrete abutments are still there, as are the remnants of steel hinges attached to them. Originally, there was third hinge at the crown of the arch as well.</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEiIdfi_WMLAjPfXG1kZVZE1KsshdYUzJJxBSomWC8tiERdrXio7_QtVGjyYpB_i1EvtZqWJwKhc91e1te7v92RX2P_5roxygAuSvPJWeiry8cZd9Lq5QUmTmlEP1H5t5hCXrp7FEMWR81BXMdgegnCbkBG7dj08FTsGjwoWHeNbgC7T7c5B410HscMufw=s1210" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1210" data-original-width="907" height="400" src="https://blogger.googleusercontent.com/img/a/AVvXsEiIdfi_WMLAjPfXG1kZVZE1KsshdYUzJJxBSomWC8tiERdrXio7_QtVGjyYpB_i1EvtZqWJwKhc91e1te7v92RX2P_5roxygAuSvPJWeiry8cZd9Lq5QUmTmlEP1H5t5hCXrp7FEMWR81BXMdgegnCbkBG7dj08FTsGjwoWHeNbgC7T7c5B410HscMufw=w300-h400" width="300" /></a></div><p>It's an attractive river setting, and it was disappointing there was no bridge.</p><p>Powys County Council have told me that the bridge was removed for safety reasons in 2013, <i>"as it had reached the end of its working life"</i>. There are no plans to replace it. I imagine the public right of way saw very little use before anyway.</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEi_8IuxBqjJ5evT_20FhGXlJ_wjuqMWIpCvU5XR45QrhI4YoQcwLW3l_65kMdotQZN3hNse4MvdPuKbd4RLlOWcb7yUgc5JV5sDygH32mNc-gEiwif2B5VtMJVTR77Ah7bo8FEH8tqLtxQvLFP2qCWEMuaX0lI2hAUD2pL_h1uJa0WPtWAcvWByXoaOvw=s1210" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1210" data-original-width="907" height="400" src="https://blogger.googleusercontent.com/img/a/AVvXsEi_8IuxBqjJ5evT_20FhGXlJ_wjuqMWIpCvU5XR45QrhI4YoQcwLW3l_65kMdotQZN3hNse4MvdPuKbd4RLlOWcb7yUgc5JV5sDygH32mNc-gEiwif2B5VtMJVTR77Ah7bo8FEH8tqLtxQvLFP2qCWEMuaX0lI2hAUD2pL_h1uJa0WPtWAcvWByXoaOvw=w300-h400" width="300" /></a></div><p>Since there was little else to see here, I have included an image from Alan Crow's book showing the previous bridges.</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEjeO7rFe8-4wFJcM4eBZianRHVjVsyIdHrfiVa4v09zM4vcolVShj9NAfv5UawuC7nhtaaMDXisxDNisw2IioHhUG0BKctpTBEh_Zt45hqlSOMd7BZwL34WK3LQ9QLde6y4C55TgnaZL5U8ElWh52rTQyNLV7tw8c0y0EsroFOOzqkbGlXDNlbqvyK0Qw=s2048" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2048" data-original-width="1411" height="400" src="https://blogger.googleusercontent.com/img/a/AVvXsEjeO7rFe8-4wFJcM4eBZianRHVjVsyIdHrfiVa4v09zM4vcolVShj9NAfv5UawuC7nhtaaMDXisxDNisw2IioHhUG0BKctpTBEh_Zt45hqlSOMd7BZwL34WK3LQ9QLde6y4C55TgnaZL5U8ElWh52rTQyNLV7tw8c0y0EsroFOOzqkbGlXDNlbqvyK0Qw=w275-h400" width="275" /></a></div><p><b>Further information:</b></p><p></p><ul style="text-align: left;"><li><a href="https://www.google.com/maps/place/52%C2%B018'58.8%22N+3%C2%B032'04.0%22W/@52.3180704,-3.533664,583m/data=!3m1!1e3!4m5!3m4!1s0x0:0x65345c105cbe8754!8m2!3d52.316325!4d-3.5344545">Google maps</a></li><li><i><a href="https://amzn.to/3DjQQVD">Bridges on the River Wye</a></i>, Alan Crow, 1995</li></ul><p></p>The Happy Pontisthttp://www.blogger.com/profile/15252272118786667592noreply@blogger.com0tag:blogger.com,1999:blog-6470543006314152962.post-31117827570221153642021-07-27T12:47:00.000+01:002021-07-27T12:47:02.493+01:00Email subscriptions update<p>Hello!</p><p>Yes, it's me.</p><p>This is a quick note aimed at the 314 readers who subscribe to get updates from the Happy Pontist via <i>feedburner</i>. That email subscription service is going to be switched off in August.</p><p>I am looking to transfer all email subscribers to the alternative platform <i>follow.it</i> instead. If you think you'd rather no longer receive emails from the Happy Pontist, that's fine, just click on any emails you get from <i>follow.it</i> to unsubscribe.</p><p>Obviously, blog posts are few and far between right now, but I'm not shutting the blog, so hopefully there will be more to come!</p>The Happy Pontisthttp://www.blogger.com/profile/15252272118786667592noreply@blogger.com1tag:blogger.com,1999:blog-6470543006314152962.post-22298108329232882772021-05-13T20:51:00.000+01:002021-05-13T20:51:00.606+01:00Yorkshire Bridges: 33. Western Bank Bridge, Sheffield<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEipsZe4wswhyphenhyphenoQ97gQpd9O-zdDWQyeUrWtxFG1smlMvgfUF0vzzg65g4oT_aIBb5Ni4BOwVezyjZ9AM1FeG7MxI40c9kIf-eOq63F8ayjrPSbNX8CExUrm-5eAiX77Bj818jPuXhD8nKm_L/s1210/Western1.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="907" data-original-width="1210" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEipsZe4wswhyphenhyphenoQ97gQpd9O-zdDWQyeUrWtxFG1smlMvgfUF0vzzg65g4oT_aIBb5Ni4BOwVezyjZ9AM1FeG7MxI40c9kIf-eOq63F8ayjrPSbNX8CExUrm-5eAiX77Bj818jPuXhD8nKm_L/w400-h300/Western1.jpg" width="400" /></a></div><br /><div>Ah, it was good to get out and see an actual bridge again.</div><div><br /></div><div>I'm not quite sure how I missed this beauty on my previous visits to Sheffield, but never mind.</div><div><br /></div><div>It was built in 1969 to a design by Ove Arup and Partners and architect <a href="https://www.smh.com.au/national/opera-house-architect-and-utzon-s-beach-ball-epiphany-moment-20201116-p56ezd.html">Yuzo Mikami</a>. I say "it", but actually there are two bridges here, as shown in the cross-section below.</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiO7hdwy9zOm-NGBVWN7xAjZKuE-9zioVDftsKK1RZdSKL9iUMjmK-kW1DydHwcLkWjw4FmrkanMvT29CmA024ZaJaWQ8_2Im7KSD1mLTllIpNzQWebu1eGFzbEa4qN7yYrBYXcnKPki0ls/s1180/westernbanksection.png" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="402" data-original-width="1180" height="136" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiO7hdwy9zOm-NGBVWN7xAjZKuE-9zioVDftsKK1RZdSKL9iUMjmK-kW1DydHwcLkWjw4FmrkanMvT29CmA024ZaJaWQ8_2Im7KSD1mLTllIpNzQWebu1eGFzbEa4qN7yYrBYXcnKPki0ls/w400-h136/westernbanksection.png" width="400" /></a></div><br /><div>The bridges carry the steeply sloping A57 Western Bank highway above a pedestrian concourse area in the University of Sheffield campus. They are two-span structures, supported on single bearings below their tetrapodal centre pier, and a pair of bearings at each end.</div><div><br /></div><div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhP38Gm9l2HzTnHcDOWPb-bxGCi9xZ3SoPtM3ZcvpGxsXWeZnSp_A8fb3d9Kmo89wCdyP4tqd4JRX6s_pGGOrufjSuHPThkgieqUY8dP7yze64YuJ-R3vxKr8DHArGETHd7Gc4SL_aCX3nL/s1210/Western10.jpg" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="907" data-original-width="1210" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhP38Gm9l2HzTnHcDOWPb-bxGCi9xZ3SoPtM3ZcvpGxsXWeZnSp_A8fb3d9Kmo89wCdyP4tqd4JRX6s_pGGOrufjSuHPThkgieqUY8dP7yze64YuJ-R3vxKr8DHArGETHd7Gc4SL_aCX3nL/w200-h150/Western10.jpg" width="200" /></a></div>The bridges were built in a period when the University campus was expanding, and the growth in road traffic had led to the highway being upgraded to a dual carriageway. Up to 10,000 pedestrians were reported to be crossing the road every day before the bridges were introduced.</div><div><br /></div><div>The reinforced concrete slab decks vary in depth, being 1.2m deep over the central support and 0.84m at the abutments. It's a subtle feature that is not immediately obvious visually due to the large footway cantilevers on the edges of the deck.</div><div><br /></div><div>Both decks are slightly curved in plan, but as can be seen in the photos, the main bridge deck slabs are straight, with the edge cantilevers varying in width to provide the curve.</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg6yK03a_TPyFP97gEyDEtrHuykLcx1xNIpqiiac7lzGxVVrZVSQaGBhb75SNWtuV7aa02oXltpfmACYASPMoHuJ8pg61Og5Pn0qv4MUoS_FyyriM-YzwQC3RsFfErUWBZ6wNxhIH59Zl3_/s1306/Western2.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="979" data-original-width="1306" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg6yK03a_TPyFP97gEyDEtrHuykLcx1xNIpqiiac7lzGxVVrZVSQaGBhb75SNWtuV7aa02oXltpfmACYASPMoHuJ8pg61Og5Pn0qv4MUoS_FyyriM-YzwQC3RsFfErUWBZ6wNxhIH59Zl3_/w400-h300/Western2.jpg" width="400" /></a></div><br /><div>From above, there is very little of interest to see. The interest is in the space created underneath the bridge. From below, this is a concrete roof held up on finger supports and providing some shelter from the weather. Glass blocks allow light through the central strip, and recently <a href="https://www.arup.com/projects/university-of-sheffield-concourse">new lighting has been installed</a> to make this a more attractive space at night.</div><div><br /></div><div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjKkD4gVWwJrz1sgazhyphenhyphenf3rA9XsYkjOkz2pWNdCdmZNqC4SXCsat5RqloL9qwGCmKsEwSFwVFhyphenhyphenaq7W3fIGnt64XsWoJKZygOShY1XeptPz-QRaHLkkukFnPCI-Mw03bTgG19z-TVmXJouE/s1210/Western3.jpg" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="907" data-original-width="1210" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjKkD4gVWwJrz1sgazhyphenhyphenf3rA9XsYkjOkz2pWNdCdmZNqC4SXCsat5RqloL9qwGCmKsEwSFwVFhyphenhyphenaq7W3fIGnt64XsWoJKZygOShY1XeptPz-QRaHLkkukFnPCI-Mw03bTgG19z-TVmXJouE/w200-h150/Western3.jpg" width="200" /></a></div>It's a classic of modernist design, with some similarities to both <a href="http://happypontist.blogspot.com/2013/11/durham-bridges-1-kingsgate-bridge.html">Kingsgate Footbridge</a> (1963) and <a href="https://en.wikipedia.org/wiki/Kylesku_Bridge">Drochaid a' Chaolais Chumhaing</a> (1984). The attraction is in its balance between the monolithic and the skeletal; it's clearly one "thing", like a sculpture, rather than one thing sitting upon another thing, like a conventional two-span road bridge.</div><div><br /></div><div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhO_zVbsHpdXxEKRBGYxGQ4khDa3bkTzHlR22kBSqxo4gozjfa5DX0KJDuJMA0OmyvAkwWiIz7z4rFSXLSupCENnvaTqgiWCn8CnkZ0THxhjQ-LaUrgi_H_0k4JqkKyS7qsIsPWLHOUfQf_/s1210/Western8.jpg" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="907" data-original-width="1210" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhO_zVbsHpdXxEKRBGYxGQ4khDa3bkTzHlR22kBSqxo4gozjfa5DX0KJDuJMA0OmyvAkwWiIz7z4rFSXLSupCENnvaTqgiWCn8CnkZ0THxhjQ-LaUrgi_H_0k4JqkKyS7qsIsPWLHOUfQf_/w200-h150/Western8.jpg" width="200" /></a></div>The tetrapod supports have an interesting blend of straight and curved geometry: the outer edges form an inverted pyramid, while the inner surfaces of each arm are profiled with the curves of two intersecting hyperbolas. I'm not 100% convinced about the way the arms meet the deck slab and wonder whether a different detail would have been preferable e.g. having the arms project slightly from the side faces of the slab to give more of a "cradling" effect.</div><div><br /></div><div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhxOVT69xezeBFrheYdhYsxCP-Mc355uoENvYTb2OibDQGJxD0NxoTAazBABREm3MC9MTF9TBTHylgixhREcjNqhOCH3L3gbABwl0gAZuDDA1_PTTpRhnUk_k0dr-sG6xC8memQzLMgi0W2/s1210/Western6.jpg" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="907" data-original-width="1210" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhxOVT69xezeBFrheYdhYsxCP-Mc355uoENvYTb2OibDQGJxD0NxoTAazBABREm3MC9MTF9TBTHylgixhREcjNqhOCH3L3gbABwl0gAZuDDA1_PTTpRhnUk_k0dr-sG6xC8memQzLMgi0W2/w200-h150/Western6.jpg" width="200" /></a></div>The sloping faces in front of the abutments were a conscious design choice, not so much to provide seating as to avoid the "tunnel" effect common to subways with vertical walls. The aim is to integrate the bridge with the adjacent landscaping. I guess the central tetrapods represent a similar visual impulse.</div><div><br /></div><div>The block seating around the supports is not original. I wonder to what extent it was added to stop drunken students from bashing their heads into the angled support struts?</div><div><br /></div><div>The concrete appears to have weathered well, and I'm left wondering why such a well-designed bridge isn't a little better known.</div><div><br /></div><div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi4Kb1p_7g8P_H4oh76Zt2Jjy62PtKXMyMpU_WHF_gO8Yabxv6ydFvaQL49zjBBfDvl2dSSbcCwmE3deXeJiYfhyphenhyphenyRtX53z3lH8Hp7YPUKfQs7k1JCAVtc1NkejPPROVH3iF6mDYY8H4v1n/s1210/Western5.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="907" data-original-width="1210" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi4Kb1p_7g8P_H4oh76Zt2Jjy62PtKXMyMpU_WHF_gO8Yabxv6ydFvaQL49zjBBfDvl2dSSbcCwmE3deXeJiYfhyphenhyphenyRtX53z3lH8Hp7YPUKfQs7k1JCAVtc1NkejPPROVH3iF6mDYY8H4v1n/w400-h300/Western5.jpg" width="400" /></a></div><br /></div><div>The article about the bridge in Arup Journal is well worth reading, including some excellent photographs, design drawings, explanations of the structural analysis, and an unexpected anecdote about students in mini-skirts.</div><div><br /></div><div>The bridge was rewaterproofed, repaired and had new bearings installed <a href="https://www.ekspan.com/media/4739/western-bank-underpass-bridge-bearing-installation.pdf">in 2016</a>.</div><div><br /></div><div><b>Further information:</b></div><div><ul style="text-align: left;"><li><a href="https://goo.gl/maps/L8msRdtPvo4dTvwD6">Google maps</a></li><li><i><a href="https://www.arup.com/perspectives/publications/the-arup-journal/section/the-arup-journal-1969-issue-4">The design and construction of Sheffield University Concourse</a></i> (Ranawake, Gordon and Tune, Arup Journal, 1969)</li><li><i><a href="https://happypontist.blogspot.com/2019/10/an-encyclopaedia-of-british-bridges-by.html">An Encyclopaedia of British Bridges</a></i> (McFetrich, 2019)</li></ul></div>The Happy Pontisthttp://www.blogger.com/profile/15252272118786667592noreply@blogger.com2tag:blogger.com,1999:blog-6470543006314152962.post-45670456281066389762021-05-08T14:51:00.000+01:002021-05-08T14:51:09.764+01:00"Link it! Masterpieces of Bridge Design" by Chris van Uffelen<p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhxTzqEwma95UFNWskwyJSE8SbkJcI7YR-2vsw_GTAqcXGm7LdPUtOanCeJCFNJE6FC2BIHcCbcT5miS4dy42AS3OXH3HESwZJzAuPRPHttCZMvxwnuumTPP6YLCW78CghPriW04d0l24JJ/s807/linkit.jpg" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="686" data-original-width="807" height="170" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhxTzqEwma95UFNWskwyJSE8SbkJcI7YR-2vsw_GTAqcXGm7LdPUtOanCeJCFNJE6FC2BIHcCbcT5miS4dy42AS3OXH3HESwZJzAuPRPHttCZMvxwnuumTPP6YLCW78CghPriW04d0l24JJ/w200-h170/linkit.jpg" width="200" /></a></div>There ought to be a name for this sort of coffee-table architecture book, churned out seemingly by the dozen every month, heavy on the photos, light on text, and filled with an uncritical gosh-gee-whizz approach to its subject. Publishers like Braun have a formula that works, whether the book is about bungalows, home conversions, factory design, corporate gardens, cinema architecture, bamboo architecture, apartment buildings, or, eventually bridges. And all those examples are just a small part of the output from one author, Chris van Uffelen.<p></p><p>Something similar can be found on architectural websites like Dezeen, Archboom, Architizer and Designboom: an ever-growing torrent of archi-gloss, much of it unedited from designer's self-promotional submissions. And make no mistake: it is responsible for a genuine and substantial dumbing down of how "design fans" perceive the built environment, such that even the worst examples of toxic architectural bloat are slurped down like nectar by an audience increasingly addicted to the hyperreal and incapable of rational analysis.</p><p>None of which is to say that I find nothing of value in <i>"Link it! Masterpieces of Bridge Design"</i> (<a href="https://www.braun-publishing.ch/en/architecture/link-it.html#">Braun Publishing</a>, 2014, 208pp).</p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhnT7uxzT_CwGSWfnscoCExzV8R0ibMzNVUiOwjBPs4FVMbEb17WPd5-y4Ecn51MQVzOvoMYwhFemOjc4rvvrcvarriNz430KFK_cd0vsqDbKexZfXsx0ibBi6uV0WcfbPnRwtvMlDfcP5V/s1352/linkit2.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="591" data-original-width="1352" height="88" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhnT7uxzT_CwGSWfnscoCExzV8R0ibMzNVUiOwjBPs4FVMbEb17WPd5-y4Ecn51MQVzOvoMYwhFemOjc4rvvrcvarriNz430KFK_cd0vsqDbKexZfXsx0ibBi6uV0WcfbPnRwtvMlDfcP5V/w200-h88/linkit2.jpg" width="200" /></a></div>This is essentially a sequel to van Uffelen's <i>"Masterpieces: Bridge Architecture + Design"</i> (2009), which <a href="https://happypontist.blogspot.com/2009/11/masterpieces-bridge-architecture-design.html">I reviewed</a> when it came out. I say "van Uffelen" as if he wrote these books, but they are actually put together by "Editorial Office van Uffelen", who provide publishers with the complete ready-made coffee-table service, even if much of that is simply emailing suitable architects and asking them to submit their marketing material. A disclaimer at the end of the book makes clear that if anything is incorrect, it's the fault of the design firms, not editors or publisher.<p></p><p>So: there's almost nothing in the book that you can't find freely on the internet, and essentially you're paying to fund the marketing efforts of the designers who participate in the publication. And yet ... there are plenty of structures and projects in this book that I was unaware of and intrigued to discover.</p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgVx1DIZOLWfiYBq458z16IRrO7TrHgRWXpG9NNCPfUa2EjO-Z_lWWVSOH149m1kdTsYCjTc3f03mLCn061gefnFVLr1zNgMyUxnJFbRaLfrIpROFRi_cllIbAUA08Zz-DsdAzDlnqyWu_l/s1347/linkit5.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="590" data-original-width="1347" height="88" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgVx1DIZOLWfiYBq458z16IRrO7TrHgRWXpG9NNCPfUa2EjO-Z_lWWVSOH149m1kdTsYCjTc3f03mLCn061gefnFVLr1zNgMyUxnJFbRaLfrIpROFRi_cllIbAUA08Zz-DsdAzDlnqyWu_l/w200-h88/linkit5.jpg" width="200" /></a></div><i>"Link It!" </i>includes a smattering of generally remarkable bridges that should be well-known to dedicated pontists: Dublin's Samuel Beckett Bridge; the Millau Viaduct; the Hovenring; the <a href="https://happypontist.blogspot.com/2017/01/french-bridges-19-passerelle-simone-de.html">Passerelle Simone-de-Beauvoir</a>; Calgary's <a href="https://happypontist.blogspot.com/2011/04/calgary-peace-bridge-in-trouble-again.html">Peace Bridge</a>; Jerusalem's <a href="https://happypontist.blogspot.com/2008/06/calatrava-mcdonalds-of-bridges.html">Bridge of Strings</a>; etc. I am sure these will be interesting and attractive examples of bridge design for the non-specialist (who are obviously the book's core audience).<p></p><p>Beyond that, there are bridges in China, Austria, Germany, Canada, the Netherlands, Belgium, Denmark, Indonesia which are interesting, in some cases attractive, and often have features that a designer could take inspiration from, or in others spot details to avoid. The quality of the designs is, inevitably, uneven, and each bridge has minimal explanation and certainly nothing in the way of criticism. There are, thankfully, only a handful of complete stinkers amongst those that have actually been built.</p><p></p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEikQp6GOGL0R7tlVS8RogImPEeXsjkWKbKBoZa9lsnQ9-CY8n89gywCOFyLLL7F2dnJ5Y5f5Z3nvw3ASHjkQs_G2XoYeqZGTzA29RvQhIRRRCaDK1osfaqDVLbkuT8dtWPtPYd3dIWFgCDF/s1345/linkit4.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="592" data-original-width="1345" height="88" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEikQp6GOGL0R7tlVS8RogImPEeXsjkWKbKBoZa9lsnQ9-CY8n89gywCOFyLLL7F2dnJ5Y5f5Z3nvw3ASHjkQs_G2XoYeqZGTzA29RvQhIRRRCaDK1osfaqDVLbkuT8dtWPtPYd3dIWFgCDF/w200-h88/linkit4.jpg" width="200" /></a></div>I mention that because the book also features a number of unbuilt bridges, generally with little or no detail on when they may be built, or whether they will happen at all. Some clearly won't, like the daft "Bouncing Bridge" proposed in Paris, the deliberately conceptual "Hydraspan" proposed for San Francisco, or the notorious Kazimierz Ludwinow Pedestrian Bridge, in Krakow, Poland.<p></p><p>There are a few designs which I would hope even the more cynical pontist would find appealing. Examples include the Wupperbrucke in Leverkusen, Germany; the timber truss Enniger Bridge in Switzerland; the Phyllis J. Tilley Memorial Footbridge in Texas; and the Green School Millennium Bridge, in Bali. Sadly, it's not hard to think of plenty of other fine bridges that didn't make the cut.</p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiXlvz0A93ac_1rZ9xmmL8Treouy-nVbDG3V4NB2Sur3iR8pEbBSGg6NaKTxCzyxY_j-S42y3E9uVNxupWIw3ig4q66IbGZtghek2rIBiipYdEclwrv1ldi_ofVQSbESUUra40OvElV4ncN/s1345/linkit3.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="591" data-original-width="1345" height="88" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiXlvz0A93ac_1rZ9xmmL8Treouy-nVbDG3V4NB2Sur3iR8pEbBSGg6NaKTxCzyxY_j-S42y3E9uVNxupWIw3ig4q66IbGZtghek2rIBiipYdEclwrv1ldi_ofVQSbESUUra40OvElV4ncN/w200-h88/linkit3.jpg" width="200" /></a></div>The photographs throughout the book are generally of an excellent quality that show off the subject matter to its best, although they are often the "day-before-opening" images beloved of the architectural press, showing the bridges pristine and generally unsullied even by people or traffic.<p></p><p>In summary, it's best to see this sort of book as a glossy brochure, assembled without any expert curation; but which can still provide some pleasant browsing if not taken too seriously.</p>The Happy Pontisthttp://www.blogger.com/profile/15252272118786667592noreply@blogger.com0tag:blogger.com,1999:blog-6470543006314152962.post-64029832747892099612021-05-02T09:00:00.006+01:002021-05-02T09:00:51.739+01:00"The Architecture of British Bridges" by Ronald Yee<p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiSQorwFlAEz_Mu-kGcpkSLBgWccaGsmKsUVrcYDOsiGhImVz2bN8drWi4HT0MMh_KMP5rqWLLWjjrRpcFawMjcVQNB5GgkXPwIW7aJ5qkqxgvjEaglBT1ngasEq8rxS4WtTWbq8btI1DWx/s1000/yee.jpg" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="1000" data-original-width="761" height="200" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiSQorwFlAEz_Mu-kGcpkSLBgWccaGsmKsUVrcYDOsiGhImVz2bN8drWi4HT0MMh_KMP5rqWLLWjjrRpcFawMjcVQNB5GgkXPwIW7aJ5qkqxgvjEaglBT1ngasEq8rxS4WtTWbq8btI1DWx/w153-h200/yee.jpg" width="153" /></a></div>Where does engineering end and architecture begin? That's the question I was left with after reading Ronald Yee's wide-ranging and informative <i>"The Architecture of British Bridges"</i> (<a href="https://www.crowood.com/details.asp?isbn=9781785007941&t=Architecture-of-British-Bridges">Crowood Press</a>, 2021, 224 pages).<p></p><p>Books on the bridges of Britain tend to fall into three camps: <a href="https://happypontist.blogspot.com/2019/10/an-encyclopaedia-of-british-bridges-by.html">big national surveys</a>; more selective surveys following the <a href="https://happypontist.blogspot.com/2019/03/britains-greatest-bridges-by-joseph.html">author's specific tastes</a>; and studies of niche topics like <a href="https://happypontist.blogspot.com/2010/07/bridges-in-britain-4-british-railway.html">railway bridges</a>. The new book by specialist bridge architect <a href="https://yee.co.uk/">Ronald Yee</a> surprised me by coming closest to the first camp.</p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiZS487wBLXKNjifVAsE7ICFX6N-bAg_y25hEhn6pVK2s_bZfwnS_vVY2u7Cg7cO2DamUKJfGmJ17moOQBRbALmZdxsjB1pTb9-nN6mnI1b8CwI9PJGkKdcrYGw37_bSjaUE0VDeSCFz8U7/s777/Yee4.png" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="777" data-original-width="596" height="200" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiZS487wBLXKNjifVAsE7ICFX6N-bAg_y25hEhn6pVK2s_bZfwnS_vVY2u7Cg7cO2DamUKJfGmJ17moOQBRbALmZdxsjB1pTb9-nN6mnI1b8CwI9PJGkKdcrYGw37_bSjaUE0VDeSCFz8U7/w153-h200/Yee4.png" width="153" /></a></div>The core of the book is a survey of bridges from around the UK, not comprehensive but very well-chosen. This is bookended by an introductory chapter on the architecture of bridges, and two final chapters on bridge parapets and lighting. There is a useful index but nothing in the way of references or bibliography.<p></p><p></p><p></p><p></p>Since much of the first chapter is given over to a layperson's guide to different structural forms, there are actually only three or four pages which specifically tackle the architecture of bridges. I had definitely hoped to read more about this, given the author's own area of expertise. There is a bit of a gap in the market here, as most books and articles about bridge aesthetics are written by engineers, not the architects who now play such a key role in bridge design.<p></p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiR1bT5s3p_pWM0eEuK2z9NOSZWdYkr6PYiswdOfh9sMFUfcfsRDfqLAn9YdnVhCLT8ByigQ7-JgUbn7XCcX3KNT9fnkN_9_wQRKuEcKXLKruxs0PD7hjBF69eCVvYVQPyYkIAPO9Izjmwr/s782/Yee1.png" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="782" data-original-width="594" height="200" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiR1bT5s3p_pWM0eEuK2z9NOSZWdYkr6PYiswdOfh9sMFUfcfsRDfqLAn9YdnVhCLT8ByigQ7-JgUbn7XCcX3KNT9fnkN_9_wQRKuEcKXLKruxs0PD7hjBF69eCVvYVQPyYkIAPO9Izjmwr/w152-h200/Yee1.png" width="152" /></a></div>Yee's own architectural approach is one that is very closely aligned to the engineering: he is not one for the outlandish or decorative. His approach to the book's topic is to <i>"show, not tell"</i>, allowing the idea of good bridge architecture to emerge through example rather than through a didactic approach.<p></p><p></p><p>The message I got from the main part of the book is that Yee sees architecture and engineering as being to some extent complementary and to some extent inseparable. Bridges from all periods are described straightforwardly, with the same attention given to how they work (structurally), as to their place in history, their visual appearance, or their local context. Yes, they may have specific architectural attributes (the description of Chester's Grosvenor Bridge includes its <i>"archivolts of red Peckforton sandston ashlar"</i> and <i>"a frieze and cornice with rectangular modillions"</i>, amongst other features; Stirling's Forthside Footbridge's <i>"visual effect is gymnastic and an undeniably spectacular sight"</i>), but these are never anything other than part of the wider story.</p><p></p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgYqQHVDaJ-i3Wg2JY2-8iEUWTCCqxWQKfEAPuG0VV6AtqmqlNZcM0MZ0UcLfpo-yfZh4_NtuRneM_C1pnhV6S_kDXm5uVOqbP3vmAxMJFnNnvSjnii2WBpdmw-HNVWp6w3kn8DnB1ANMtP/s777/Yee3.png" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="777" data-original-width="595" height="200" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgYqQHVDaJ-i3Wg2JY2-8iEUWTCCqxWQKfEAPuG0VV6AtqmqlNZcM0MZ0UcLfpo-yfZh4_NtuRneM_C1pnhV6S_kDXm5uVOqbP3vmAxMJFnNnvSjnii2WBpdmw-HNVWp6w3kn8DnB1ANMtP/w153-h200/Yee3.png" width="153" /></a></div>This leaves many of the individual bridge entries a little dry, even where the bridges themselves can be seen to have some degree of special interest. In other cases, Yee ventures more of an opinion and I'd certainly like to have seen more of this.<p></p><p>The key strength of the book lies in how well the entries have been curated, and illustrated with generally excellent photographs. Given that Yee is well known for his sketches and drawings, I'd love to have seen more of those - they are few and far between.</p><p></p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhvESoQWWl0rj8h-sqXz1mZ0Zu8ARZoOhNixXdosDzp3moRHlWlWmNDdx_DU0q_QeKB4lIRNW6rJrNaA1KO4lokWrA8PMGEX7BeKVmTLr0I51unB7ipmBBUzu57b0cxgDm7lyn52AFpnKq3/s777/Yee2.png" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="777" data-original-width="596" height="200" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhvESoQWWl0rj8h-sqXz1mZ0Zu8ARZoOhNixXdosDzp3moRHlWlWmNDdx_DU0q_QeKB4lIRNW6rJrNaA1KO4lokWrA8PMGEX7BeKVmTLr0I51unB7ipmBBUzu57b0cxgDm7lyn52AFpnKq3/w153-h200/Yee2.png" width="153" /></a></div>I have read many books about bridges in Britain, but I still found plenty here that I was unaware of or which has not been celebrated previously in print. It surveys an excellent range of often exemplary bridges, at all scales great and small.<p></p><p>Presenting the bridges in a gazetteer format, structured by materials and bridge typology, does mean that much is left unsaid about architecture: the way in which bridge design in Britain moved through phases of craft construction, master builders, the era of "scientific" engineering, and the slow and then more rapid rise of architects as the leaders of the design narrative. Yee's book therefore leaves room for some very different treatments of the subject, and hopefully others will step into the breach.</p>The Happy Pontisthttp://www.blogger.com/profile/15252272118786667592noreply@blogger.com1tag:blogger.com,1999:blog-6470543006314152962.post-52905665894044903332021-04-22T20:50:00.000+01:002021-04-22T20:50:33.024+01:00"Transporter Bridges: an Illustrated History" by John Hannavy<div><div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiMsTPb7wQu4-D5poRXO33Lp3qHfjCJ2DQ0IYiSvqAc8sdKsHB58NgfMmQckADtatKe2X5n2dh7ECnYDtFHfO5W2Diji8JZfZCYBcw70lSQWcIwMcqjALhENPKryyqu-DVwHiY9HgyYKKm0/s1600/Hannavy.jpg" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="531" data-original-width="404" height="200" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiMsTPb7wQu4-D5poRXO33Lp3qHfjCJ2DQ0IYiSvqAc8sdKsHB58NgfMmQckADtatKe2X5n2dh7ECnYDtFHfO5W2Diji8JZfZCYBcw70lSQWcIwMcqjALhENPKryyqu-DVwHiY9HgyYKKm0/w152-h200/Hannavy.jpg" width="152" /></a></div><i>Transporter Bridges</i> by <a href="https://www.johnhannavy.co.uk/books/transporter-bridges-an-illustrated-history/">John Hannavy</a> (<a href="https://www.pen-and-sword.co.uk/Transporter-Bridges-Hardback/p/17164">Pen and Sword</a>, 268pp, 2020) is, I think, the first book to bring these unusual structures together in a comprehensive record. Subtitled <i>"An Illustrated History"</i>, this is indeed a highly pictorial and well-detailed account of what was a very short-lived type of structure. Nineteen were built between 1893 and 1916, before the growth in motor traffic made them a less attractive form of river crossing.</div><div><br /></div><div>The concept of a transporter bridge dated back to the mid-19th century. At a time when tall boats still used major rivers, there were essentially four ways to transport vehicles across such an obstacle. Ferry boats were common, but could only carry a few vehicles at a time, and could be unreliable. Fixed bridges were the highest-capacity, most reliable solution, but expensive both in construction and land-take. Moveable bridges were, in their earlier years, complex and expensive, and suitable only for moderate spans. The transporter bridge could cover longer spans, but carrying loads more in line with those on a ferry.</div><div><br /></div><div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgwmRjaTo6sa-GSlmltpqr8WAMyUDPwcJcwURJoaIjg2kORVD8c1d7W2BxgSGRMO9BJBbxjgHPLwknvqiPGRfU2JeATYoVdoAtUYvt55I4-yoT2VkZKisa1aZBThva-NgwD630lH-iLw8bc/s589/hannavy3.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="377" data-original-width="589" height="128" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgwmRjaTo6sa-GSlmltpqr8WAMyUDPwcJcwURJoaIjg2kORVD8c1d7W2BxgSGRMO9BJBbxjgHPLwknvqiPGRfU2JeATYoVdoAtUYvt55I4-yoT2VkZKisa1aZBThva-NgwD630lH-iLw8bc/w200-h128/hannavy3.jpg" width="200" /></a></div><div>Hannavy documents early proposals for transporter bridges in detail: H.N. Houghton's idea for a railway crossing in New York (1852); J.W. Morse's plan for a similar crossing (1869); Charles Smith's proposal in Middlesbrough (1873); and others.</div></div><div><br /></div><div>However, the first proposal to be built was the Viscaya bridge at Portugalete near Bilbao, completed in 1893. The designers Alberto Palacio and Ferdinand Arnodin took out patents for the transporter concept, and Arnodin went on to complete eight more such bridges.</div><div><br /></div><div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiUvPDcMtBiQj_0MEBPqxqb2vuO3CnSwkmiEr7acmljbykLipzOTr4ZWnu7PFvAZx05Yf9HP7j4kTAzSHOWt7c2klnr49urYSY6Mafv_j1eyHAmOlSClvLIlfT98_Ju8t7uxbnjySSrKZrX/s589/hannavy4.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="377" data-original-width="589" height="128" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiUvPDcMtBiQj_0MEBPqxqb2vuO3CnSwkmiEr7acmljbykLipzOTr4ZWnu7PFvAZx05Yf9HP7j4kTAzSHOWt7c2klnr49urYSY6Mafv_j1eyHAmOlSClvLIlfT98_Ju8t7uxbnjySSrKZrX/w200-h128/hannavy4.jpg" width="200" /></a></div>Hannavy's history covers most of the transporter bridges with relative brevity - I say relative as they all get plenty of detail. He takes the story right up to recent decades where new transporter bridges have been proposed (e.g. at Royal Victoria Dock, Nantes, Marseilles and Brest). Of these, the <a href="https://happypontist.blogspot.com/2011/09/london-bridges-16-royal-victoria-dock.html">Royal Victoria Dock Bridge</a> is the only that was built, but its transporter gondola was never installed.</div><div><br /></div><div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjL_x9Ig0i4G5DP1Q024fP3TEMG7p7XBwCR0D3jcnOoPjvdk_EPxLi_c0-CUUj717Vq5ZDZuUi6YFfimYjxFiOU2Sb4j-BBXzzYnhaigHFH_rTtwk9PavkhXLuznVgPTVyKCPIE4yIsm7E6/s589/hannavy5.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="377" data-original-width="589" height="128" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjL_x9Ig0i4G5DP1Q024fP3TEMG7p7XBwCR0D3jcnOoPjvdk_EPxLi_c0-CUUj717Vq5ZDZuUi6YFfimYjxFiOU2Sb4j-BBXzzYnhaigHFH_rTtwk9PavkhXLuznVgPTVyKCPIE4yIsm7E6/w200-h128/hannavy5.jpg" width="200" /></a></div>Beyond the basic history, the book discusses the "Systeme Arnodin" in detail, and there are chapters covering five of the few surviving transporter spans at length as fine examples of the type: the Viscaya bridge, Newport Transporter Bridge, the <a href="https://happypontist.blogspot.com/2013/11/teesside-bridges-1-middlesbrough.html">Tees Transporter Bridge</a>, Crosfield's <a href="https://happypontist.blogspot.com/2011/11/merseyside-bridges-10-warrington.html">Warrington Transporter Bridge</a> (and its now-demolished sibling), and the Rochefort Bridge. A further chapter considers the Widnes-Runcorn Bridge, which was closed in 1961. All five of the transporter bridges ever built in the UK are therefore given close attention.</div><div><br /></div><div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh26FQ-XsbDWD0njMv7XGfhfmR0Us2mUTKOKsXEvwuQNzrr8CuA5h3U-WER5shWd5SP7rE3JBmVaKReVckU88fbAeAVYRNmVirauzEiL_-bY3jCgKJamSEbWbsP6ma5hNZ4yVU3Zz91CnjF/s589/hannavy6.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="377" data-original-width="589" height="128" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh26FQ-XsbDWD0njMv7XGfhfmR0Us2mUTKOKsXEvwuQNzrr8CuA5h3U-WER5shWd5SP7rE3JBmVaKReVckU88fbAeAVYRNmVirauzEiL_-bY3jCgKJamSEbWbsP6ma5hNZ4yVU3Zz91CnjF/w200-h128/hannavy6.jpg" width="200" /></a></div>Each of these is covered thoroughly, with quotes from contemporary journals and an excellent variety of historic and recent photographs. Hannavy's research has clearly been in-depth. The chapter on the Rochefort bridge is particularly interesting, as it mainly documents the massive refurbishment project undertaken to prolong the life of the bridge and to restore it closer to the original Arnodin design.</div><div><br /></div><div>In addition to the main chapters, the book concludes with a series of one-page summaries of all the known transporter bridges both built and unbuilt.</div><div><br /></div><div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj-RqSpPWNgp_tskVoebJRT-xzOtzdNabCzElNvrOd1Zp02Fl5WV2UA1w0PPKcwntmClFhEu9ZberQgV1XZEc5zAmp19MM2SP0A5vdB0HPDFltDYk_yEBHXxNXYomSqIq4lQGjAh9oZJcSb/s589/hannavy7.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="377" data-original-width="589" height="128" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj-RqSpPWNgp_tskVoebJRT-xzOtzdNabCzElNvrOd1Zp02Fl5WV2UA1w0PPKcwntmClFhEu9ZberQgV1XZEc5zAmp19MM2SP0A5vdB0HPDFltDYk_yEBHXxNXYomSqIq4lQGjAh9oZJcSb/w200-h128/hannavy7.jpg" width="200" /></a></div>This is, without any doubt, the definitive book on transporter bridges, and essential for anyone with an interest in them. More generally, it should appeal to those with a broader interest in historic bridges. It is not entirely faultless, unfortunately, as there is no bibliography and no referencing of any sort. This is a shame for any serious researchers, but probably not a big issue for the more general reader.</div>The Happy Pontisthttp://www.blogger.com/profile/15252272118786667592noreply@blogger.com0tag:blogger.com,1999:blog-6470543006314152962.post-90606471811299631882021-04-18T20:22:00.000+01:002021-04-18T20:22:43.900+01:00"Bill Brown's Bridges" by David Boxall<p>I've remarked in the past how few books there are on the great bridge designers of the 20th century, other than one or two of the earliest decades such as <a href="https://en.wikipedia.org/wiki/Robert_Maillart">Robert Maillart</a> and <a href="https://en.wikipedia.org/wiki/Othmar_Ammann">Othmar Ammann</a>. Even many bridge design professionals will struggle to name designers comparable with the likes of the nineteenth century's Telford, Stephenson and Brunel.</p><p>In the 20th century, the increase in scientific understanding of structural design and consequent specialisation made large projects more and more the province of a broad team rather than a singular man and his support office. This was especially the case where the scale or sensitivity of projects required decision-making to be collective rather than dictatorial.</p><p>Of course, it was always the case that the big names were often just those who fronted up the work of a broader team. That's nothing new, although it does sometimes seem as if in the late 20th and early 21st century the only entities that can be credited for a bridge design are the engineering corporation or the architect. Individual engineers, not so much.</p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhp7rkNlj1SHr3F6xdBaZQnNBQ0geOtivikZ_2htZAEbZOHGteSAKCkSS4gQ0FmnSIRoDmqATrkN9VFvdkVETgdFZl3tUrhxLCiTdHXpqM3yV8zLQppse3V6Ii86qAAzfOTYxMVN2yoBr-Z/s2048/brown1.jpg" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em; text-align: center;"><img border="0" data-original-height="2036" data-original-width="2048" height="199" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhp7rkNlj1SHr3F6xdBaZQnNBQ0geOtivikZ_2htZAEbZOHGteSAKCkSS4gQ0FmnSIRoDmqATrkN9VFvdkVETgdFZl3tUrhxLCiTdHXpqM3yV8zLQppse3V6Ii86qAAzfOTYxMVN2yoBr-Z/w200-h199/brown1.jpg" width="200" /></a><span style="text-align: left;"><div style="text-align: left;">With all that in mind, I was keen to read <i>"Bill Brown's Bridges"</i> by David Boxall (301 Publishing, 2015, 148pp, available from <a href="http://www.b2.co.uk/bill-browns-bridges.aspx">b2.co.uk</a>), a biography of one of Britain's most successful suspension bridge engineers, who worked on the Forth Road Bridge, Severn Bridge, Erskine Bridge, Humber Bridge, two bridges over the Bosphorus straits, and on unbuilt proposals for the Messina Strait Bridge. Brown has been credited with the aerodynamic box girder design for the Severn Bridge, which radically changed the economy and feasibility of major suspension bridges.</div></span></div><p></p><p>Boxall runs a marketing and design agency, but was previously manager of Brown Beech Associates. This book is very much an "official biography", produced with the cooperation of Brown's wife Celia, and its aim is to document and cement the legacy of one of Britain's most successful bridge engineers.</p><p>Born in south Wales in 1928, Brown studied engineering at Southampton and then completed a PhD at Imperial College. His family background was technical in that his grandfather and father were both cabinetmakers. On graduating from Imperial in 1951, Brown was fortunate to go straight into employment with the engineer <a href="https://en.wikipedia.org/wiki/Gilbert_Roberts">Gilbert Roberts</a> at Freeman Fox.</p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgsN0og6Z9beSHJA3NCLFhTCeIee_oAeTcXX6OwO_ULlqyzOrbOq8-4LRNTkNiZxVTwp3mohKN-ejNyMvzgQYJDZK0y_09vTQ_KRqNlKUmvund5m9mtuQPhhv4LGl-k1izw_ZYgVqOFudHx/s2048/brown6.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1080" data-original-width="2048" height="211" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgsN0og6Z9beSHJA3NCLFhTCeIee_oAeTcXX6OwO_ULlqyzOrbOq8-4LRNTkNiZxVTwp3mohKN-ejNyMvzgQYJDZK0y_09vTQ_KRqNlKUmvund5m9mtuQPhhv4LGl-k1izw_ZYgVqOFudHx/w400-h211/brown6.jpg" width="400" /></a></div><p></p><p>Roberts was one of the top engineers of the day, responsible for the structural design of the Dome of Discovery for the Festival of Britain. He had worked with Sir Ralph Freeman on the design of the <a href="https://happypontist.blogspot.com/2014/06/sydney-harbour-bridge.html">Sydney Harbour Bridge</a> (1932), and on a suspension bridge on the <a href="https://en.wikipedia.org/wiki/Chirundu_Bridge#The_Otto_Beit_Bridge_(1939)">Zambia - Zimbabwe border</a> (1939).</p><p>Over the course of eighteen years until Roberts retired in 1969, Brown was exposed to progressively more challenging engineering and greater levels of responsibility. By the time he became a partner in the Freeman Fox firm in 1970, he had worked on some truly exceptional projects.</p><p>His early years included work on major cranes, and a major steel arch structure, <a href="https://en.wikipedia.org/wiki/Adomi_Bridge">Adomi Bridge</a> in the Ghana (1957). Developments in welding and higher-strength structural steels during the 1950s were to prove essential for what would follow in the 1960s.</p><p><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhhLLVJyaaY6MFln0nkN2p-ECEEbpkkxZLBxBbbIv45qGe4GgS0dTLGPaPRw-OdjUyGnwvNubW9zBtztCKil0wYIqON_kwUoNMOnf0ftEjwYxBNxjZJb6aXLJrBquVYVcdlw2G5tsczx2Jh/s2048/brown3.jpg" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em; text-align: center;"><img border="0" data-original-height="2013" data-original-width="2048" height="197" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhhLLVJyaaY6MFln0nkN2p-ECEEbpkkxZLBxBbbIv45qGe4GgS0dTLGPaPRw-OdjUyGnwvNubW9zBtztCKil0wYIqON_kwUoNMOnf0ftEjwYxBNxjZJb6aXLJrBquVYVcdlw2G5tsczx2Jh/w200-h197/brown3.jpg" width="200" /></a>Freeman Fox's design team, led by Gilbert Roberts, were appointed (alongside Mott, Hay and Anderson) to develop designs for both the <a href="https://en.wikipedia.org/wiki/Forth_Road_Bridge">Forth Road Bridge</a> (1964) and <a href="https://en.wikipedia.org/wiki/Severn_Bridge">Severn Bridge</a> (1966). These were spans well in excess of the largest suspension bridge recently built in the UK (<a href="https://happypontist.blogspot.com/2011/09/west-country-bridges-4-tamar-bridge.html">Tamar Bridge</a>, 1961). It had been two decades since the collapse of the ill-fated <a href="https://en.wikipedia.org/wiki/Tacoma_Narrows_Bridge">Tacoma Narrows bridge</a>, but aerodynamic concerns remained high in engineers' minds.</p><p></p><p>Both the Severn and Forth bridges were initially designed to be built using the truss decks then seen as the norm. Fortuitously, an accident in wind tunnel testing during design of the Severn bridge led to a model being mostly destroyed. The book recounts that for the replacement model Brown sketched out a very different slender box-girder geometry, that could be built quickly out of plywood and used for the remaining testing. Severn went on to become the first large suspension bridge built using an aerodynamically stable box girder, a major innovation.</p><p>What the book doesn't say is that the slender box-girder concept was not new to the Severn crossing: German engineer <a href="https://happypontist.blogspot.com/2009/07/fritz-leonhardt-1909-1999-art-of.html">Fritz Leonhardt</a> had proposed the same idea for the Tagus suspension bridge in 1960, albeit with two separated box girders rather than just one. Indeed, much of the development of welding and stiffened steel plates for bridge construction had been undertaken in Germany.</p><p>The book goes big on Brown's role here (and elsewhere) as an innovator, but says nothing about the Severn Bridge's legacy of problems: fatigue in the inclined suspension hangers, issues with the quality of welded plate, and the need for expensive strengthening. Innovation is never without risk, and on this scale, the consequences can be significant.</p><p><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiFU2MIJbqXjQ-yl3PBUq-2ZdYeoRaog9ZvCapg1ac8o-nDRgKk2u-71DmcBFKD_yeMwRBFgVPGlLVomjgBCxnWGKV3_PaOSFhpM_uCjjLp4KhA74BWuiYPnTyhSiyxVjmTZblTAugBq5iL/s2048/brown2.jpg" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em; text-align: center;"><img border="0" data-original-height="2048" data-original-width="2042" height="200" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiFU2MIJbqXjQ-yl3PBUq-2ZdYeoRaog9ZvCapg1ac8o-nDRgKk2u-71DmcBFKD_yeMwRBFgVPGlLVomjgBCxnWGKV3_PaOSFhpM_uCjjLp4KhA74BWuiYPnTyhSiyxVjmTZblTAugBq5iL/w199-h200/brown2.jpg" width="199" /></a>Box girders were also used by Freeman Fox for the nearby Wye Bridge, the Erskine Bridge, and for the <a href="https://www.westgatebridge.org/">West Gate Bridge</a> in Melbourne, Australia. The latter collapsed, killing 35 people, in October 1970, and Brown was amongst the senior Freeman Fox staff summoned to testify at the subsequent inquiry in Australia. Boxall records partner Dr Oleg Kerensky's view that the collapse was the fault of the contractors, and that the design had been sound. This is misleading: Freeman Fox's design calculations and site supervision were <a href="https://www.westgatebridge.org/sites/default/files/downloads/report-of-royal-commission.pdf">condemned as completely inadequate</a> by the inquiry.</p><p>At the time the West Gate Bridge collapsed, Freeman Fox had already been working on plans for a new suspension bridge across the Bosphorus for three years. This adopted both the aerofoil deck from the Severn Bridge, and also the triangulated layout for the suspension hangers, an idea which had seen little if any use elsewhere.</p><p>Completed in 1973, the first <a href="https://en.wikipedia.org/wiki/Bosphorus_Bridge">Bosphorus Bridge</a> was the longest span outside the USA at the time it was built, and is quite possibly Roberts and Brown's finest achievement. Freeman Fox took on significant overall responsibility for guiding and supervising the project, not just its design, and Brown relocated to Istanbul for most of the construction phase.</p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhVBcEOUJ6JnrwZ3Oku5Sp_N9hiazs4VFOltvxT5b5l-lEET8Z4QjvOEwgxc8bWWgaBPJxRMxElbMdRGnXGBT11jaoY8qVrFg9MQ8ZAzWxkXMnM59baZr2mvC2yJrn_ZRGXbed20w-aXprl/s2048/brown5.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1067" data-original-width="2048" height="209" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhVBcEOUJ6JnrwZ3Oku5Sp_N9hiazs4VFOltvxT5b5l-lEET8Z4QjvOEwgxc8bWWgaBPJxRMxElbMdRGnXGBT11jaoY8qVrFg9MQ8ZAzWxkXMnM59baZr2mvC2yJrn_ZRGXbed20w-aXprl/w400-h209/brown5.jpg" width="400" /></a></div><p>By the time of the even longer <a href="https://en.wikipedia.org/wiki/Fatih_Sultan_Mehmet_Bridge">Second Bosphorus Bridge</a> (1988), Brown had left Freeman Fox and set up his own firm, Brown Beech Associates (in a huff, to paraphrase the book's account). His role this time was as the client's technical advisor, rather than as designer. This bridge adopted conventional vertical hangers, unlike the triangulated ones used on Severn and the previous Bosphorus span, and a few years later the latter bridge had its hangers replaced with vertical cables as well.</p><p></p><p></p><p>In his later years, Brown worked as a consultant on a number of structures, including the <a href="https://en.wikipedia.org/wiki/Strait_of_Messina_Bridge">Messina Strait Bridge</a> and the <a href="https://en.wikipedia.org/wiki/Great_Belt_Fixed_Link">Storebaelt East Bridge</a>, both developing concept design proposals and advising on more specific issues such as cable-spinning techniques. He passed away aged 76, in 2005. The book includes a gallery of images of nine key structures that he worked on, and they truly are an incredible CV.</p><p></p><p></p><p>I think it's fair to say that this official biography is a partial account - broader and more balanced accounts of the development of twentieth century suspension bridges are <a href="https://happypontist.blogspot.com/2012/11/in-wake-of-tacoma-by-r-scott.html">available</a> <a href="https://happypontist.blogspot.com/2018/01/history-of-modern-suspension-bridge-by.html">elsewhere</a>. However, the book is well written, well illustrated and well presented. There are dozens of great photographs of some truly epic bridges, and it's great to see a twentieth-century British bridge engineer recognised in this way.</p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg3LMK4QzqnagaXvFmhXyNBptNg-qOD6iIbVbvsfltM-5v6b5YVvTbOoL8PyNJBQiLgRfZjVyHbacUP0ZjQfJ7TlSNLH3R3j_doraMnPzsycLrdABV338GOg0aSAGV9_6X4MpKf9TFL0pv3/s2048/brown7.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1082" data-original-width="2048" height="211" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg3LMK4QzqnagaXvFmhXyNBptNg-qOD6iIbVbvsfltM-5v6b5YVvTbOoL8PyNJBQiLgRfZjVyHbacUP0ZjQfJ7TlSNLH3R3j_doraMnPzsycLrdABV338GOg0aSAGV9_6X4MpKf9TFL0pv3/w400-h211/brown7.jpg" width="400" /></a></div><p></p><p>There was a period from the completion of the Severn Bridge to the completion of the Humber Bridge when it appeared that Britain had firmly re-established itself in the vanguard of long-span bridge design, and as part of the Freeman Fox team Bill Brown was clearly central to that.</p>The Happy Pontisthttp://www.blogger.com/profile/15252272118786667592noreply@blogger.com1tag:blogger.com,1999:blog-6470543006314152962.post-34849954404325849812021-04-13T19:48:00.001+01:002021-04-13T19:48:49.493+01:00"Fowler's Bridges" by Aidan Bell<div>Sir John Fowler is best known (with Sir Benjamin Baker) as one of the engineers responsible for the Forth Railway Bridge, completed in 1890, a masterpiece of Victorian civil engineering. During his illustrious career, <a href="https://en.wikipedia.org/wiki/Sir_John_Fowler,_1st_Baronethttps://en.wikipedia.org/wiki/Sir_John_Fowler,_1st_Baronet">Fowler</a> was responsible for many other bridges and railways, including much of what is now the Circle Line on the London Underground.</div><div><br /></div><div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg1qwRavoXLpwDIn-KhCzsL1h_yvTI0C9j8QNWVMu9anQQArcjDOlIKb1TpZ5KMk-jWOUUCn-FZazcxQ1ECR-N34rGpvlScGmacW_H9xjufbL7EAjBg924rheabnGYPaQ9qBGglJ5xy7Cfr/s766/Fowler0.jpg" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="766" data-original-width="541" height="200" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg1qwRavoXLpwDIn-KhCzsL1h_yvTI0C9j8QNWVMu9anQQArcjDOlIKb1TpZ5KMk-jWOUUCn-FZazcxQ1ECR-N34rGpvlScGmacW_H9xjufbL7EAjBg924rheabnGYPaQ9qBGglJ5xy7Cfr/w141-h200/Fowler0.jpg" width="141" /></a></div>Aidan Bell's book <i>"Fowler's Bridges"</i> (self-published and available from <a href="https://www.biblio.com/book/fowlers-bridges-aidan-bell/d/1361452011">biblio.com</a>, ISBN 978-1-5272-7661-1, 190pp, 2020) deals with the engineer's most famous works only in passing. Instead it is an in-depth study of the estate that Fowler developed at <a href="https://canmore.org.uk/site/105386/braemore-house">Braemore</a>, near Ullapool in Scotland, and the bridges that he built there, many with <a href="https://en.wikipedia.org/wiki/Benjamin_Baker_(engineer)">Baker</a>'s assistance.</div><div><br /></div><div>Fowler's life story is one of almost constant upward progress. Born in 1817, Fowler set himself on a career in engineering as soon as he left school. His first few years saw him apprenticed to John Towlerton Leather, George Leather and John Urpeth Rastrick. He rapidly took on increasing responsibility, before setting up independently at the age of 26 in 1843. It was the period of railway mania, and Fowler was in the thick of it, taking on chief engineer roles and promoting schemes in Parliament.</div><div><br /></div><div>By 1849, Fowler was elected to the Council of the Institution of Civil Engineers, going on to become its President in 1865. By that time his consulting practice had grown substantially and was working on over 70 large projects each year. Fowler's army of assistants were based at premises in London, where he also had his main residence.</div><div><br /></div><div>Also in 1865, Fowler bought the first of two estates near Ullapool in northern Scotland, Braemore, merging it two years later with the adjacent Inverbroom estate. This was to be his holiday home, and he would spend two months of each year there. A new house was built, with innovations including hydro-electric power for electric lighting, and many improvements were made to access around the estate. Fowler had become a proper Victorian gentleman, eventually adding a Baronetcy to his Knighthood, enjoying the Highland hunting life, and entertaining guests at what must have seemed a very remote place to some.</div><div><br /></div><div>In this painstakingly detailed book, Aidan Bell recounts the story of Fowler's life and career, and documents the Braemore estate, providing detailed descriptions of several "miniature" bridges which Fowler had installed within the landscape. The estate was very different in character to many of those of the landed gentry, with its rough terrain and steep river gorges. The only comparable landscaped Victorian estate seems to be William Armstrong's <a href="https://happypontist.blogspot.com/2014/02/northumbrian-bridges-4-cragside-bridge.html">Cragside</a>.</div><div><br /></div><div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgFWaH3jezSf8wd2CrXWXyE76Tf8QKuOujDpAV5gHSSF6m7w7gkf5qjEmC5a859c9qy_ThM4brR5QeTXENyqM4wvr2FbhCHXlufGZ2yWmcoI6CH2iZdevRejwlYkR_U6cfuzjfwGhoSEH2n/s2048/Fowler2.jpg" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="2048" data-original-width="1420" height="200" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgFWaH3jezSf8wd2CrXWXyE76Tf8QKuOujDpAV5gHSSF6m7w7gkf5qjEmC5a859c9qy_ThM4brR5QeTXENyqM4wvr2FbhCHXlufGZ2yWmcoI6CH2iZdevRejwlYkR_U6cfuzjfwGhoSEH2n/w139-h200/Fowler2.jpg" width="139" /></a></div>Two of the estate bridges are relatively well-known: <a href="https://www.nts.org.uk/visit/places/corrieshalloch-gorge/highlights/the-suspension-bridge-and-cultural-landscape">Corrieshalloch Suspension Bridge</a>, and <a href="https://historicbridges.org/bridges/browser/?bridgebrowser=unitedkingdom/auchindreanbridge/">Auchindrean Bridge</a>. The bridge at Corrieshalloch stands out for its situation above a waterfall, allowing visitors spectacular views of the river gorge. The Auchindrean bridge spans a less dramatic location, but is notable as the largest lenticular bridge surviving in Scotland today. It has similarities to Brunel's larger <a href="https://happypontist.blogspot.com/2011/09/west-country-bridges-5-royal-albert.html">Saltash bridge</a>.<br /></div><div><br /></div><div>The other bridges are less spectacular, but interesting in how Braemore was treated very differently to other Victorian estates. As an engineer, Fowler seems to have had little interest in the sort of faux-classicism that decorated the property of other wealthy landowners. The Braemore bridges are economically appropriate solutions to difficult terrain, rather than ornamental. They are for the most part aesthetically unspectacular, encouraging the visitor to look away from the bridge and admire the scenic grandeur instead.</div><div><br /></div><div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgW2lNQG7X49JJ6jGPfNKw3S7JFcId7eA05LH6nwazGFwbo_TLljD53QksvGai6OC3SYJArS0zknY_LZcNglIHMMu4JV2m01-0E_T5DfaTJLzvd2bmob8JkYGcMxmVZfvaoRG-5ya4dwSzn/s2048/Fowler3.jpg" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="2048" data-original-width="1333" height="200" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgW2lNQG7X49JJ6jGPfNKw3S7JFcId7eA05LH6nwazGFwbo_TLljD53QksvGai6OC3SYJArS0zknY_LZcNglIHMMu4JV2m01-0E_T5DfaTJLzvd2bmob8JkYGcMxmVZfvaoRG-5ya4dwSzn/w130-h200/Fowler3.jpg" width="130" /></a></div>Bell's book is heavy on detail. Many of the bridges no longer exist, but each bridge site is described in detail, with photographs and even diagrams to illustrate the structural behaviour of each bridge. It is, to be fair, so much detail that it is likely to be too much for the casual reader, but I certainly enjoyed its thoroughness. The book may be best suited to anyone with an interest in Fowler himself, or Scottish historic bridges generally, or the way in which an estate's development illustrated the expertise and philosophy of an engineering owner.</div><div><br /></div><div>For me it raises interesting questions around taste. The desire of others to ornament their lands with the mock-Palladian, columns and porticos and pediments taken out of context and plopped down amidst soft green vistas seems to be a taste that has survived today. Prince Charles is perhaps the most notorious modern proponent of a belief that beauty can be found mainly in the past, and that the tics and tropes of the classical are a timeless aesthetic, rather than a pastiche shorn of meaning when taken out of context.</div><div><br /></div><div>As an engineer, Fowler is more likely to have seen the problem that needed solving as one of spanning an obstacle, rather than decorating a view. The functional nature of the Braemore bridges suggests a love of a more natural landscape, and a desire to make his intrusions into it as modest as was possible. It seems an aesthetic approach to admire and emulate: bridges creating new spaces to admire the surroundings rather than to function primarily as sculpture. There are designers still working today who could benefit from that philosophy.</div>The Happy Pontisthttp://www.blogger.com/profile/15252272118786667592noreply@blogger.com1tag:blogger.com,1999:blog-6470543006314152962.post-56747825424402160812021-04-12T13:52:00.000+01:002021-04-12T13:52:17.103+01:00The return of the Happy Pontist<p>You may have spotted this blog has been a little quiet last year, and especially recently. This is the first time I've posted since the beginning of November. There haven't been many opportunities to visit bridges, and generally more pressing things to do than blogging anyway.</p><p>So ... I do have a few books about bridges that I could review, so I'll start posting some of those shortly.</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiDNg37rhWiqzoTFXAybMTD1ysLOZ_pBc9uIlsiKoD_e2kcE5Vc1bKbv0TcA8eEChkHjrQUkO5iS235nebKcThmk6Non7fgpxiJx0tj31MxwOVpLBD2ExUcnDHo_Pvx_zNgAuHobyeNbp0_/s2048/books.jpeg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1331" data-original-width="2048" height="260" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiDNg37rhWiqzoTFXAybMTD1ysLOZ_pBc9uIlsiKoD_e2kcE5Vc1bKbv0TcA8eEChkHjrQUkO5iS235nebKcThmk6Non7fgpxiJx0tj31MxwOVpLBD2ExUcnDHo_Pvx_zNgAuHobyeNbp0_/w400-h260/books.jpeg" width="400" /></a></div><p>And if there is something in the world of bridges that you really think I should feature here, please do let me know, via the comments.</p><p>So long as it is not this.</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj4pco54cWN18FPjs3TDJ2LzYMu16ntnxkEEbNls1QGO9E00w5n7OtkMapn8TS4Isznf6T9Djy0K2KjF51wOkvA4sYoIsHi2Vjl_at8_DM3vdyPhjE95f_g404yEZqi6BQyTIYRhMFEdA1d/s1261/YellowSea.png" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="669" data-original-width="1261" height="213" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj4pco54cWN18FPjs3TDJ2LzYMu16ntnxkEEbNls1QGO9E00w5n7OtkMapn8TS4Isznf6T9Djy0K2KjF51wOkvA4sYoIsHi2Vjl_at8_DM3vdyPhjE95f_g404yEZqi6BQyTIYRhMFEdA1d/w400-h213/YellowSea.png" width="400" /></a></div><p>Or this.</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhaMA70UTIBsO66LyjQHPRUGxStzTiaRJvyPRZ896xT-5v1OeVy1LQ_0cWw3tYmdZrjSu0FgWQ641L36yHa-z9CrciYz-GRWsNmvgzS7IB8zNAgyErtwBCrIrzCI2UzhlIeJ5Z-5zANxU-v/s1394/Callebaut.png" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="933" data-original-width="1394" height="268" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhaMA70UTIBsO66LyjQHPRUGxStzTiaRJvyPRZ896xT-5v1OeVy1LQ_0cWw3tYmdZrjSu0FgWQ641L36yHa-z9CrciYz-GRWsNmvgzS7IB8zNAgyErtwBCrIrzCI2UzhlIeJ5Z-5zANxU-v/w400-h268/Callebaut.png" width="400" /></a></div><p>Or this. Definitely not this!</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhgIxbgDo8cF9tWEYWp-QvJXt7QYA1oqAqYYjm-THEtTUTPz-pNhXzsKsEc1lil3T2EzTFXLPKFJvw8yEaKOmE_S30VkRQjD8HTWrw0vMV8B80nIaY54YbVyhhK9uT9CUFPnDaU5r2vcNfH/s2048/reverse-arch.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1152" data-original-width="2048" height="225" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhgIxbgDo8cF9tWEYWp-QvJXt7QYA1oqAqYYjm-THEtTUTPz-pNhXzsKsEc1lil3T2EzTFXLPKFJvw8yEaKOmE_S30VkRQjD8HTWrw0vMV8B80nIaY54YbVyhhK9uT9CUFPnDaU5r2vcNfH/w400-h225/reverse-arch.jpg" width="400" /></a></div>The Happy Pontisthttp://www.blogger.com/profile/15252272118786667592noreply@blogger.com6tag:blogger.com,1999:blog-6470543006314152962.post-38625055060925504802020-11-01T16:00:00.002+00:002020-11-01T16:00:48.828+00:00"Bridging: by Foot and Bicycle" by Ney & Partners<div><div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiH-11qJFbfHnBkUCveavSbH-O0y2ET7-PcnPMk_lgn0Jnywhts4zEabosLoYGBZQ9-CyqRq9eGZZDMTA276ZrMnZ8J3wl3H_4HkliRTzRrwRr6r8dxD7tQuH-WUZTfiFut1eaDD9aj2RB7/s1600/Ney-book.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="415" data-original-width="513" height="323" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiH-11qJFbfHnBkUCveavSbH-O0y2ET7-PcnPMk_lgn0Jnywhts4zEabosLoYGBZQ9-CyqRq9eGZZDMTA276ZrMnZ8J3wl3H_4HkliRTzRrwRr6r8dxD7tQuH-WUZTfiFut1eaDD9aj2RB7/w400-h323/Ney-book.jpg" width="400" /></a></div><div><br /></div>Here is an excellent book devoted to the <i>designers du jour</i> in the world of bridges, <a href="https://www.ney.partners/new-book-on-ney-partners-bridging-by-foot-and-by-bicycle-be.html">Ney and Partners</a>. Once past its ungrammatical title, <i>Bridging. By Foot and Bicycle</i> (<a href="https://www.bookstorming.com/archibooks">Archibooks</a>, 264pp, 2019) is an excellent and very well-presented survey of the firm's pedestrian bridge <i>oeuvre</i>, filled with photos, visualisations, drawings, diagrams and informative text (in both French and English). As with the firm's bridges, the book is not completely without its flaws, but I can recommend it to anyone with a serious interest in the very best bridge design.</div><div><br /></div>An introduction titled <i>"A bridge has to be designed!"</i> by Laurent Ney sets the tone. Ney reports his experience working on a project with a large multi-disciplinary firm, who apparently responded with embarrassed silence when Ney asked "Who designed the bridge?" While this hardly rings true (such firms are obviously well populated with people who design bridges) his point is that the norm in design firms when presented with a bridge project is not to design from a <i>tabula rasa</i>, but to select and adapt from an existing structural typology. His argument is that there is no real "design" in this approach.<div><br /></div><div>This is the very opposite of Ney's own <i>modus operandi</i> which is (to at least some extent), to see how context and constraints can point the way to creative opportunities, minimising preconceptions wherever possible. This book illustrates that effectively, explaining in detail the design decisions that were made on the various projects featured.</div><div><br /></div><div>From the outset, this also highlights a lacuna that recurs throughout the book. It is the designer's perspective, and largely a history of various designed objects and why they are how they are. There is little in the way of self-criticism, and essentially no space for the voice of those who commission or use these bridges. This is not uncommon in an architectural monograph, and in this case, where much of the discussion is inevitably somewhat technical, the sense that there are people on the bridges and they may have something to tell us sometimes vanishes entirely.</div><div><br /></div><div>The technical element in the book is inevitable given the superlative engineering at the core of many of Ney and Partners' bridges. Sometimes, their astonishing bridges seem to be the output of a designer who is operating as a <i>naïf</i>, ignorant of the conventions of bridge design and hence able to devise solutions that would never even enter the peripheral vision of an experienced engineer. At other times, they seem the work of an <i>auteur</i>, someone with an in-depth understanding of the bridge engineering craft but the desire to pursue excellence and never accept compromise.</div><div><br />Fellow engineers often admire Ney and Partners' bridges because this approach - creative, challenging, courageous - leads to structures which are remarkable in their geometric perfection and economy of detail, slimmed down well beyond what others ever attempt, let alone achieve. This is why the technical issues are key throughout the book and it could never be purely about the architectural aspects of design.</div><div><br /></div><div>Although the bridge designs featured often take the idea of refinement to extremes, the bridges are only rarely completely rational in their conception. It's always clear that intuition has been applied, and subjective choices made. This is particularly the case in the first few bridges presented, which share a theme of history and context.</div><div><br /></div><div>The as-yet unbuilt <a href="https://www.ney.partners/project/21095.html">Poissy Footbridge</a> is a proposal for a new bridge on the site of the remnants of a historic bridge across the River Seine. The historic <a href="https://fr.wikipedia.org/wiki/Ancien_pont_de_Poissy">Pont de Poissy</a> was largely destroyed in 1944, and never rebuilt. The Ney design follows the same alignment but flies above the remaining bridge piers, supported from tetradactyl steel supports sitting in between the original masonry. The new bridge's longest span is 93m, yet the deck is formed from a single, ultra-slender folded steel plate. The impression is of a gently undulating ribbon, dancing across the river, dipping down over the existing piers but darting back away from them as if suspended on air. It is both a little incongruous, giving the initial impression of being structurally unreasonable, and also rather stunning.</div><div><br /></div><div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEihGAW_a4tIjl5rnLVK1GSd97MxTZeUiMYszUe77jGHzwITWanxbJr4XrmSXHI3RILAwuASEF10wHIEaSBsvlZRXLgOzp246KD1U3WAZMKRhxISKcsa_Sh8fHv7qWI6TImU-B2XnAxVFr5x/s2048/20201024_163822.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1690" data-original-width="2048" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEihGAW_a4tIjl5rnLVK1GSd97MxTZeUiMYszUe77jGHzwITWanxbJr4XrmSXHI3RILAwuASEF10wHIEaSBsvlZRXLgOzp246KD1U3WAZMKRhxISKcsa_Sh8fHv7qWI6TImU-B2XnAxVFr5x/s320/20201024_163822.jpg" width="320" /></a></div><br /></div><div><a href="https://www.ney.partners/project/dejima-footbridge.html">Dejima Footbridge</a>, completed in 2017 in Nagasaki is very different but illustrates some of the same aspects of the Ney philosophy. This is a cantilever bridge, arranged with one fixed end so that the "free" end imposes as little load as possible on the more archaeologically sensitive of the two river banks. The two edge girders feature multiple rows of stiffening plates, with the web perforated in a visually interesting manner. However, the stiffeners are to a great extent decorative, and the shape of the girders gives the visual impression that the bridge functions like an arch. It's a beautiful structure, but the engineering and architecture are not integrated in the way that many other Ney designs achieve.</div><div><br /></div><div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgu5IklM_wdXM2Yzw70RefOwZOIRXrEYXOtRAx5XmZr97GLB51m3SKO8V7B7ram0OI-o_sHg7K2WhMLoMlvOU3SKMybkWs_bYAAWTi2Fi_FOcmVAO-CkaK-JAk1NQtwht_HsLPa3qeIF7DN/s2048/20201024_163849.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1649" data-original-width="2048" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgu5IklM_wdXM2Yzw70RefOwZOIRXrEYXOtRAx5XmZr97GLB51m3SKO8V7B7ram0OI-o_sHg7K2WhMLoMlvOU3SKMybkWs_bYAAWTi2Fi_FOcmVAO-CkaK-JAk1NQtwht_HsLPa3qeIF7DN/s320/20201024_163849.jpg" width="320" /></a></div><div><br /></div>The book's discussion of the <a href="https://www.ney.partners/project/tintagel-castle-footbridge.html">Tintagel Footbridge</a> serves to illustrate the point that Ney and Partners don't entirely ignore conventional typologies, but that their design process can allow them to take or adapt those standard forms in interesting and site-appropriate ways. At this site, Ney's analysis of the normal bridge forms led them towards an arch as a visually and contextually desirable proposal for the site.</div><div><br /></div><div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgHelvXbyFqbIHtw9djHOo3Uz6Qqcb_Y8HQqWQkaoO1fR5v_kPEyLYxjhsC6Bvx83pMRTsLtfNrBZuHDIG6UC9pnWBAJ985Z_edP7jDse90_mFGgTDA1YqCP_Ab_nydEG3SbcPHeGUna2TL/s2048/20201024_164014.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1755" data-original-width="2048" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgHelvXbyFqbIHtw9djHOo3Uz6Qqcb_Y8HQqWQkaoO1fR5v_kPEyLYxjhsC6Bvx83pMRTsLtfNrBZuHDIG6UC9pnWBAJ985Z_edP7jDse90_mFGgTDA1YqCP_Ab_nydEG3SbcPHeGUna2TL/s320/20201024_164014.jpg" width="320" /></a></div><div><br /></div>A key issue at Tintagel was the difficult access for construction, leading to consideration of a bridge which was built by cantilevering from its supports (a <a href="http://happypontist.blogspot.com/2014/06/sydney-harbour-bridge.html">well-trodden method</a> for building metal arch bridges). The bridge as-built retains the cantilever form, as making it into a genuine arch would have been structurally far more challenging (a result of the sag curve of the pathway, and the consequences for thermal restraint).</div><div><br /></div><div>It's a spectacular bridge and the engineering and architectural ideas are well-explained in this book, but very little is said about how its users find it (especially with such filigree parapets <a href="http://happypontist.blogspot.com/2015/12/tintagel-castle-shortlist-announced.html">high above a chasm</a>, and with <a href="http://happypontist.blogspot.com/2017/06/tintagel-castle-footbridge-submitted.html">a gap in the floor</a> at midspan).</div><div><br /></div><div>The same is true of a structure like the <a href="https://www.ney.partners/project/bridge-spoor-noord.html">Park Footbridge</a> in Antwerp. This is one of a number of designs where Ney and Partners apply a "subtractive process", defining a stable shape and form, generally in thin sheet metal, and then looking to see what metal is unnecessary and can be cut away (the carbon balance of reduced material versus increased fabrication process is never discussed). The structure here is a hybrid between a bowstring arch and a box girder, although, as with many architects, that's a term that's never used - after all, who would celebrate being able to walk through the interior of a girder (<a href="https://happypontist.blogspot.com/2020/09/welsh-bridges-18-britannia-bridge.html">it's not 1850 any more</a>)?</div><div><br /></div><div>It's an amazing work of structural engineering, absent all the bolts and stiffeners that a normal box girder interior displays. The webs are perforated in a manner that takes account of levels of stress, but is not entirely determined by that, with far more material left in place than can be structurally necessary - compare a proper bowstring arch where a handful of cables suffice to connect the arch to the bridge deck. It looks like an amazing experience to walk through but ... why is it a covered bridge at all? Will the patterns of illumination inside be tolerated by pedestrians susceptible to flicker? And is a floor-rail, an obvious trip-hazard, really the best way to stop cyclists bashing their heads on the girder web? To me, it feels like the uncompromising desire to maintain the purity of the design object results in a design that is not completely comfortable.</div><div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEieiEr8QQIZwQ8TT0WDv2v6emW_9AYhFTqEp-VtQ9P9bYMgNP2-wBlwPFSh0N4X9_isZ0A5-ZeZEbpj68Lt5ZmSba2biJ-jM02KW5DNgG9wMLtxjVnbA6P8MCsltHujrqd66vD4bqYmWRdm/s2048/20201024_163921.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1719" data-original-width="2048" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEieiEr8QQIZwQ8TT0WDv2v6emW_9AYhFTqEp-VtQ9P9bYMgNP2-wBlwPFSh0N4X9_isZ0A5-ZeZEbpj68Lt5ZmSba2biJ-jM02KW5DNgG9wMLtxjVnbA6P8MCsltHujrqd66vD4bqYmWRdm/s320/20201024_163921.jpg" width="320" /></a></div></div><div><br /></div><div>This is not the only Ney bridge where this can be said. The <a href="https://www.ney.partners/project/vluchthaven-footbridge-ijdock.html">Vluchthaven Footbridge</a> in Amsterdam has the same sinuous deck plate as the Poissy design, and an ingenious parapet design. The client was keen to address the common Amsterdam problem where bridge parapets serve as a favoured place for bicycles to be parked and locked. Ney and Partners came up with an elegant parapet design with all verticals - no top rail or handrail. If someone were foolish enough to lock a bicycle here, it could just be lifted off. It's smart and very well detailed - but handrails are a good thing for many bridge users, especially the elderly or infirm who may want to take the opportunity to stop and briefly secure a handhold. This does not appear to a bridge for stopping on.</div><div><br /></div><div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh7-b9ahtGbBKvfnqd_coJE03wpgl5j9-HdxcA-fC9xxgSIeaZhup5nuDv8wsf4FkzhKgsn-7KTzrcKkF4ersAK306dJftRJAQdEgm2y_M53A81Fbrk0qGJE0g9pzDWyfcelo9FGRtPYXkf/s2048/20201024_163947.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1688" data-original-width="2048" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh7-b9ahtGbBKvfnqd_coJE03wpgl5j9-HdxcA-fC9xxgSIeaZhup5nuDv8wsf4FkzhKgsn-7KTzrcKkF4ersAK306dJftRJAQdEgm2y_M53A81Fbrk0qGJE0g9pzDWyfcelo9FGRtPYXkf/s320/20201024_163947.jpg" width="320" /></a></div><div><br /></div><div>A very different result from the subtractive approach mentioned above is the <a href="https://happypontist.blogspot.com/2009/11/knokke-footbridge.html">Knokke Footbridge</a>, which I discussed right back in 2009. This is, in my view, one of the firm's masterpieces, using one curved steel plate to satisfy the requirements both of transverse load distribution (a curved skin acting in tension) and as the primary longitudinal structure (sharing the characteristics of a suspension bridge and also of a Robert Maillart arch, inverted). The Y-shaped bridge supports, and the way they hold up the deck, are brilliant.</div><div><br /></div></div><div>In writing this book review I've been drawn to writing about the flaws in these designs, because I feel that the monograph style of the book (uncritical, celebratory) and the presentation entirely from the designer's perspective (their subjective view is privileged over anything else) do beg for some degree of challenge.</div><div><br /></div><div>However, Ney and Partners are easily one of the best bridge designers working today, bringing together a very rare blend of imagination with the superlative technical ability required to turn their audaciousness into reality. They operate way beyond the level of the vast majority of bridge designers.</div><div><br /></div><div>The breadth and variety of their designs shows that they do take context seriously (contrast their designs, for example, with someone like Calatrava). The detailing of their bridges is frequently exquisite, and the book's photographs and technical drawings make that abundantly clear. I can't imagine a bridge designer who wouldn't enjoy and learn from this book, and non-specialists should also find their work well worth discovering in more detail.</div>The Happy Pontisthttp://www.blogger.com/profile/15252272118786667592noreply@blogger.com0tag:blogger.com,1999:blog-6470543006314152962.post-27734621356136020882020-09-30T21:36:00.001+01:002020-09-30T21:36:37.281+01:00Welsh Bridges: 20. Llantysilio Chain Bridge<div class="separator" style="text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjkHeQ6QmbXQ2ACcP5e50XDAC0uXlWw8m0EzEFhYodyeh8GWcKxQ8O9ycpK_X60C_7BgCQXIXQLRUiGDCPeN6rfxTPmzxOz2vPo_UnsgHVryr572Kc08k5PxQqs7IiCFuI8zQ-CDVJqUb5g/s1613/Llantysilio2.jpg" style="margin-left: 1em; margin-right: 1em; text-align: center;"><img border="0" data-original-height="1210" data-original-width="1613" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjkHeQ6QmbXQ2ACcP5e50XDAC0uXlWw8m0EzEFhYodyeh8GWcKxQ8O9ycpK_X60C_7BgCQXIXQLRUiGDCPeN6rfxTPmzxOz2vPo_UnsgHVryr572Kc08k5PxQqs7IiCFuI8zQ-CDVJqUb5g/w400-h300/Llantysilio2.jpg" width="400" /></a></div>
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This bridges goes by a number of names - Berwyn Chain Bridge may be equally as appropriate. Signs at the site just call it "The Chain Bridge". It is neither a Listed Building nor a Scheduled Monument, which will only be surprising if you incorrectly imagine that our heritage bodies are competent.</div>
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The first bridge across the River Dee at this location was the work of local man <a href="https://www.peoplescollection.wales/story/378243">Exuperius Pickering</a>, variously described as an entrepreneur or a "coalmaster". Pickering was looking for a way to transport his coal and other materials between the Llangollen Canal (1808) and Telford's recently improved London to Holyhead Road, without paying tolls to cross <a href="http://www.engineering-timelines.com/scripts/engineeringItem.asp?id=391">Llangollen Bridge</a>. Conceived in 1814, his bridge was completed in 1818.</div>
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This was a period of rapid development in cable or chain-supported bridges within the United Kingdom. Granted, the Winch Bridge, an iron chain catenary structure, had been built over the River Tees in 1741. However, it was the early 19th century when cable and chain bridges took off, with stayed bridges in <a href="https://structurae.net/en/structures/galashiels-wire-bridge">Galashiels</a> (1816), <a href="https://structurae.net/en/structures/king-s-meadows-bridge">King's Meadow Bridge</a> (1817) and <a href="http://happypontist.blogspot.com/2010/12/scottish-bridges-15-dryburgh-abbey.html">Dryburgh Abbey Bridge</a> (1817, rebuilt as a suspension bridge in 1818), and the <a href="http://happypontist.blogspot.com/2010/08/northumbrian-bridges-1-union-chain.html">Union Chain Bridge</a> (1820, suspension bridge). Things advanced rapidly enough for Robert Stevenson to present an article surveying these and other designs in 1821, as well as proposing his own bridge at Cramond, an <a href="https://en.wikipedia.org/wiki/Underspanned_suspension_bridge">underspanned suspension bridge</a>, which was never built.</div>
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Pickering's bridge sits right in the middle of this chronology. Happily for posterity, drawings of the bridge were made by the French traveller <a href="https://en.wikipedia.org/wiki/Joseph_Dutens">Joseph-Michel Dutens</a> (see below). These show the bridge to be an underspanned suspension bridge, with eyebar chains supporting the deck, and an additional tension rod below this, perhaps to enhance stability. The bridges I mentioned above were well-reported, and it's often stated that Stevenson was the first to propose an underspanned suspension bridge, and James Smith's Micklewood Bridge (1831) the first to be built. In reality, Pickering got there first, although how much of an improvement his structure was over a simple catenary bridge might be doubtful.</div>
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The first drawing by Dutens shows half of the bridge (it was a three-span structure), while the second drawing gives cross-sections and details of the chains. A dozen chains passed below the bridge deck to provide support.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj2JJpXDVZUUSL9K6c7_FPEfIrECqujn2dxYtcQJSOQTNEU0bPEiEGwxrXGjgLx1jAz_weh5r9uhOm5wH7B7KppOZkrx2mJw3mwjoi6YlB9t9rGuI4362qlJKt5g1I-hMgVJvgI8kuiRqRE/s1600/1stBridgeDutens.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="521" data-original-width="1316" height="157" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj2JJpXDVZUUSL9K6c7_FPEfIrECqujn2dxYtcQJSOQTNEU0bPEiEGwxrXGjgLx1jAz_weh5r9uhOm5wH7B7KppOZkrx2mJw3mwjoi6YlB9t9rGuI4362qlJKt5g1I-hMgVJvgI8kuiRqRE/w400-h157/1stBridgeDutens.jpg" width="400" /></a></div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhiN4o1waaBFnsp194s6RyZ-spdlCj4FWqbwgBieVex2mGAEiDGGwrssUPKQseGIduNH2lzf_6y2YYnoKrM30FAicsP7Kq-VWxK83BlUXMPblWgQm1AC7iAhUzy5EuzpZzOGGk9CdQYZL_e/s753/1stBridgeDutensDetails.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="742" data-original-width="753" height="394" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhiN4o1waaBFnsp194s6RyZ-spdlCj4FWqbwgBieVex2mGAEiDGGwrssUPKQseGIduNH2lzf_6y2YYnoKrM30FAicsP7Kq-VWxK83BlUXMPblWgQm1AC7iAhUzy5EuzpZzOGGk9CdQYZL_e/w400-h394/1stBridgeDutensDetails.jpg" width="400" /></a></div>
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In addition to the drawings, photographs of Pickering's bridge survive, although showing it enhanced on one side by a timber truss.</div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgarmOxarFVmXWJaZZMCNkYkdB5nRmRKMU9-yGjtQ5mqkeJi6ku83Z3IaOnrNDpGcQL5UUZE6TQk0-A8FFRytfOarZYhct7fUwX4VKMQAzBvGihci1rbbosQ-ie8zo24w22uV6sLeYAhQ5d/s900/Firstbridge.png" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="709" data-original-width="900" height="315" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgarmOxarFVmXWJaZZMCNkYkdB5nRmRKMU9-yGjtQ5mqkeJi6ku83Z3IaOnrNDpGcQL5UUZE6TQk0-A8FFRytfOarZYhct7fUwX4VKMQAzBvGihci1rbbosQ-ie8zo24w22uV6sLeYAhQ5d/w400-h315/Firstbridge.png" width="400" /></a></div>
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The bridge lasted remarkably well, until it became unsafe and was dismantled in 1870. In 1876, Henry Robertson, owner of Brymbo Ironworks, rebuilt the three spans and re-used the original chains, again adopting the underspanned system (photograph below). This one was destroyed in flooding in 1928.</div>
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<img border="0" data-original-height="1080" data-original-width="1436" height="301" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhWrrRhBilB9aOpwcCg27_DkeXVJG2lPExlWZZGFXueH-NHEgmBzY0GMRSeUmETOqhfgmkySmBNxwmqrq1vysfuJeboCr4frjYBHNppoCnjSnK_HAf_OLuxBjmcHpT7s__bi0ZbuYudiblg/w400-h301/Chain_Bridge_Hotel%252C_Berwyn_Valley%252C_Llangollen%252C_Wales-LCCN2001703517.tif.jpg" width="400" /></div>
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Roberton's son rebuilt the bridge the following year, but this time with only a single pier in the river. The chains were re-used, but now to form a suspension bridge, with three suspension chains on each edge, and two stiffening chains connected along the deck underneath.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi_1gHQXYrqZs_M7XZ99ZS5eWSdRiuh2xS8iDcY6LPw_tgv7HdZoLknlmlN6IFzqLsfQnnhzp_pi3XxKNV-AkqK48xdvqJmRtS_PGN321ZQmbArbuosombeakAEoeFXDG0M0hF31V_3oLqQ/s1600/Llantysilio7.jpg" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em; text-align: center;"><img border="0" data-original-height="1201" data-original-width="1600" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi_1gHQXYrqZs_M7XZ99ZS5eWSdRiuh2xS8iDcY6LPw_tgv7HdZoLknlmlN6IFzqLsfQnnhzp_pi3XxKNV-AkqK48xdvqJmRtS_PGN321ZQmbArbuosombeakAEoeFXDG0M0hF31V_3oLqQ/s200/Llantysilio7.jpg" width="200" /></a>One tower sits on an outcrop of rock within the river, and the other on the river wall at the north edge. The river tower was protected by a large concrete pier, rendering the new bridge far less susceptible to flood damage.</div>
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The chains at the south end of the bridge were anchored into the ground, while at the north end they pass over the adjacent Chainbridge Hotel and were anchored into rock high above the canal. The deck chains were anchored into the ground using an adjustable tensioning system.</div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiLuoGmgvLGARc1cWJxWcfj1qxmAls6e2vr7QOn36f3gI1fTUD86I2wfHtyIBagVJR4ucBuV3XvzJ4ZOZTXTN_47X8oMsJQ7UW5YlVctgTJPDp1igRc_kgaAZFUA2rdUfFXwsbdXdOupI64/s1632/Llantysilio4.jpg" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em; text-align: center;"><img border="0" data-original-height="1224" data-original-width="1632" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiLuoGmgvLGARc1cWJxWcfj1qxmAls6e2vr7QOn36f3gI1fTUD86I2wfHtyIBagVJR4ucBuV3XvzJ4ZOZTXTN_47X8oMsJQ7UW5YlVctgTJPDp1igRc_kgaAZFUA2rdUfFXwsbdXdOupI64/s200/Llantysilio4.jpg" width="200" /></a>A pair of bars hang downwards from each chain link, and these are connected to a triangulated system of lower hangers. These in turn carry the lower deck chains and the timber deck.</div>
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The bridge was load-tested with 45 people when it opened, and lasted reasonably well, becoming gradually more dilapidated until being closed as unsafe in 1984. In 2014-15, it was completely refurbished, with all the metalwork carefully dismantled and then reinstated.</div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjf9_2AWtgji27ba-SyjIMEjQN2y1UHp_RpcFsTG4f2lK7SnHdWlTWZJhoYwKsou-ClgCDDvTq4tF5unrIl7Ue7V9E3nLdLI0ocYoBa5PrwbDA5ABw-L6vzo2jgkJxGVmU6AkDQvlfrdaZi/s1632/Llantysilio1.jpg" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="1632" data-original-width="1224" height="200" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjf9_2AWtgji27ba-SyjIMEjQN2y1UHp_RpcFsTG4f2lK7SnHdWlTWZJhoYwKsou-ClgCDDvTq4tF5unrIl7Ue7V9E3nLdLI0ocYoBa5PrwbDA5ABw-L6vzo2jgkJxGVmU6AkDQvlfrdaZi/s200/Llantysilio1.jpg" width="150" /></a>The works were completed by local firm Shemec Ltd to a design by consultants <a href="https://uk.ramboll.com/projects/ruk/chain-bridge">Ramboll</a>. The engineers completed a careful structural assessment of the bridge, determining that even if corroded ironwork was replaced, it could not carry anywhere near modern loading requirements, being limited to 1.5 kPa of load. This equates to roughly 5 tonnes of load on the 24m main span, or around 60 people. Llangollen Town Council, who had taken over responsibility for the bridge, agreed that this was sufficient. Warning signs at the end of the bridge request that no more than ten people use it at once.</div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh9tRyWZm0colPcHSzuXWew6DYlrZpgT_R3Pks64JuCnikQIERTf9hURiBKOI_S_9ycOlGSw8nj4IbxGJCeY6obv7gOLlGKoLIPvMrlmWYVIcXw3QcuwGzhAO_yxusXDY4OUgnR1NpcINoY/s1613/Llantysilio5.jpg" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em; text-align: center;"><img border="0" data-original-height="1613" data-original-width="1210" height="200" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh9tRyWZm0colPcHSzuXWew6DYlrZpgT_R3Pks64JuCnikQIERTf9hURiBKOI_S_9ycOlGSw8nj4IbxGJCeY6obv7gOLlGKoLIPvMrlmWYVIcXw3QcuwGzhAO_yxusXDY4OUgnR1NpcINoY/s200/Llantysilio5.jpg" width="150" /></a>The reconstruction works are well documented in a <a href="https://structurae.net/en/literature/conference-paper/refurbishment-of-llangollen-chainbridge">paper</a> by Ramboll and in photos on the <a href="https://www.facebook.com/media/set/?vanity=chainbridgeproject&set=a.768759556531676">Chain Bridge Project</a> website. I'm not clear what proportion of the original metalwork was preserved and reused, but new pieces were fabricated in mild steel to match the existing details and dimensions wherever any piece could not be reused. All the chain pins had to be replaced. Nonetheless, in the rebuilt bridge it is claimed that these are the oldest bridge suspension chains in Britain to remain in use.</div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh4mEeIFHv2LHyb5F8X8dpvGVMtUXr-JMnKDErm_5CtgNOrO-6riAdn0xNpQexFrm0khi4yrnmS5sqmfHDXo9Kr36ZgMUr06_nxD2gEudLzfO7Xq4Bwsg7DQ4cCQnSrGsMeAmS8w42ZRl3Q/s1613/Llantysilio6.jpg" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em; text-align: center;"><img border="0" data-original-height="1210" data-original-width="1613" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh4mEeIFHv2LHyb5F8X8dpvGVMtUXr-JMnKDErm_5CtgNOrO-6riAdn0xNpQexFrm0khi4yrnmS5sqmfHDXo9Kr36ZgMUr06_nxD2gEudLzfO7Xq4Bwsg7DQ4cCQnSrGsMeAmS8w42ZRl3Q/s200/Llantysilio6.jpg" width="200" /></a>Prior to the refurbishment, there was no parapet remaining on the bridge. The reconstruction introduced a series of new parapet posts, a tensioned upper cable, and a mesh infill system. I'm not sure how well these match any parapet that had been there in the past, but I doubt the new system is compliant with normal modern standards.</div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgE1ldTqznCTt54Td0KvhzQv0mR3Ta1yM6QRH9MumOW1aPbpJ3ITaZooY9OPoNOpcuK9Ca0Of63vFkDnLDUeERM0SymCRHxoDfdnrrd96pf4dqE1In_N_1FvyvyDnw_zrw0ZSst0F_Z4B1G/s1613/Llantysilio9.jpg" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em; text-align: center;"><img border="0" data-original-height="1613" data-original-width="1210" height="200" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgE1ldTqznCTt54Td0KvhzQv0mR3Ta1yM6QRH9MumOW1aPbpJ3ITaZooY9OPoNOpcuK9Ca0Of63vFkDnLDUeERM0SymCRHxoDfdnrrd96pf4dqE1In_N_1FvyvyDnw_zrw0ZSst0F_Z4B1G/s200/Llantysilio9.jpg" width="150" /></a>Indeed it's interesting to compare the refurbishment work at Llantysilio with what was done at Brabyns Park Bridge in Marple, which I discussed in <a href="https://happypontist.blogspot.com/2020/09/manchester-bridges-24-brabyns-park.html">a recent post</a>. The chain bridge project is an exemplary piece of conservation engineering, where even though the structure is not Listed, it has been treated with integrity and the original details preserved as closely as possible. The engineers sensibly recognised that compliance with modern standards would have been entirely inappropriate. By contrast, the Marple structure is Listed Grade II, but senseless attempts to impose modern standards on it have largely ruined its appearance (although thankfully not irreversibly).</div>
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The Llantysilio Chain Bridge is unique both in the complex history of its surviving structural fabric, and in its form and details. It is well worth visiting, in a setting within view of two other fine bridges, and with plenty more to see within walking distance.</div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiNyefI9cHlgDZjeftjFGgJ-oH83Ymh_4olZ84iulgviqa6bmz9fnZVu-a1zdkKfi3L810RlzzO0NkqUFhIsBVh_7vJ5T9JWpzJ2vaKR-5oCLb1oSPsWuo0j-SGn0zEfDs1PWNX-pMm3FyG/s1613/Llantysilio3.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1210" data-original-width="1613" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiNyefI9cHlgDZjeftjFGgJ-oH83Ymh_4olZ84iulgviqa6bmz9fnZVu-a1zdkKfi3L810RlzzO0NkqUFhIsBVh_7vJ5T9JWpzJ2vaKR-5oCLb1oSPsWuo0j-SGn0zEfDs1PWNX-pMm3FyG/s400/Llantysilio3.jpg" width="400" /></a></div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiL9sw_nbkur73gpizpp0r__qNJUOpiwH1CnsfVlrgWoNscjTjsjtk3X9z6t0xW244Ur-2Pciiv8agDQO7agOtS-AozUcGt9uoyPtDxMbLLWx5lXtZvPzYKnh1lhRw-YXzoscK5H0gSdQRJ/s1613/Llantysilio8.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1210" data-original-width="1613" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiL9sw_nbkur73gpizpp0r__qNJUOpiwH1CnsfVlrgWoNscjTjsjtk3X9z6t0xW244Ur-2Pciiv8agDQO7agOtS-AozUcGt9uoyPtDxMbLLWx5lXtZvPzYKnh1lhRw-YXzoscK5H0gSdQRJ/s400/Llantysilio8.jpg" width="400" /></a></div>
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<b>Further information:</b><br />
<ul>
<li><a href="https://goo.gl/maps/4pXSujEQm9BgvnJM8">Google maps</a></li>
<li><a href="https://en.wikipedia.org/wiki/Chain_Bridge_(Berwyn)">Wikipedia</a></li>
<li><a href="http://www.engineering-timelines.com/scripts/engineeringItem.asp?id=1409">Engineering Timelines</a></li>
<li><a href="https://structurae.net/en/structures/llantysillio-chainbridge">Structurae</a></li>
<li><a href="https://www.gracesguide.co.uk/Berwyn_Chain_Bridge">Grace's Guide</a></li>
<li><a href="https://www.coflein.gov.uk/en/site/24054/details/llantisilio-chain-bridge-berwyn">Coflein</a></li>
<li><a href="https://www.peoplescollection.wales/collections/377355">People's Collection Wales</a></li>
<li><a href="https://www.facebook.com/chainbridgeproject">Chain Bridge Project</a></li>
<li><a href="https://andrew-gale.com/blog/2016/08/01/the-chainbridge-documentary/">The Chain Bridge Documentary</a> (video)</li>
<li><a href="https://www.plaskynastoncanalgroup.org/pontcysyllte/chain-bridge-llangollen/">Plas Kynaston Canal Group</a></li>
<li><a href="https://structurae.net/en/literature/conference-paper/refurbishment-of-llangollen-chainbridge"><i>The Refurbishment of Llangollen Chainbridge</i></a> (Marginson / Matthews, Footbridge 2017)</li>
</ul>
The Happy Pontisthttp://www.blogger.com/profile/15252272118786667592noreply@blogger.com0tag:blogger.com,1999:blog-6470543006314152962.post-60692081206204196032020-09-27T21:00:00.000+01:002020-09-27T21:00:04.040+01:00Welsh Bridges: 19. Lôn Las Ogwen Footbridge<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi_YW20nn5vIOwCd_oMozBJBu6bIg1lqBheCZun8LtaGg92dFqPVdnPqQ93YiHsgR2z4GyM3UhMMDmg0MDyzQa9A0JvtVQ0GBUoxOSRAsLiSkPiUTFtSwUS5Ph9bL6JLowFSF1oHz80KIYz/s1600/LonLasOgwen2.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1000" data-original-width="1600" height="250" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi_YW20nn5vIOwCd_oMozBJBu6bIg1lqBheCZun8LtaGg92dFqPVdnPqQ93YiHsgR2z4GyM3UhMMDmg0MDyzQa9A0JvtVQ0GBUoxOSRAsLiSkPiUTFtSwUS5Ph9bL6JLowFSF1oHz80KIYz/s400/LonLasOgwen2.jpg" width="400" /></a></div>
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Not far from the Britannia and Menai Bridges, the dedicated pontist may happen upon this lesser-known footbridge.<br />
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It carries the <a href="https://www.sustrans.org.uk/find-a-route-on-the-national-cycle-network/lon-las-ogwen">Lôn Las Ogwen</a>, a walking and cycling route, over the A4244 highway. The trail follows the line of the former <a href="https://en.wikipedia.org/wiki/Penrhyn_Quarry_Railway">Penrhyn Quarry Railway</a>, which was closed in 1962.<br />
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The footbridge diverts from the original line of the railway, presumably to allow a small railway junkyard to be preserved on the south abutment of the original railway bridge.<br />
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I don't know who designed the bridge, possibly local consultancy YGC, but it was fabricated by D. Hughes Welding and Fabrications, and built by contractor Mulcair Ltd. At a guess, the main span probably doesn't exceed 20m.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEibK6nzXgHDprVb0fpSX6clac9Rww_uTnpQs-sq2dz0VBJAA7p1LZ97H-mhGD3rAuwSCwQBaUXOkFTUxxzCBC-6NYSwa1E0UY6-BuGpnBDg_jFxxB2RQUF33RyvgmRmisiVN8Pntn8b3Es-/s1600/LonLasOgwen3.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="797" data-original-width="1600" height="198" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEibK6nzXgHDprVb0fpSX6clac9Rww_uTnpQs-sq2dz0VBJAA7p1LZ97H-mhGD3rAuwSCwQBaUXOkFTUxxzCBC-6NYSwa1E0UY6-BuGpnBDg_jFxxB2RQUF33RyvgmRmisiVN8Pntn8b3Es-/s400/LonLasOgwen3.jpg" width="400" /></a></div>
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At first glance, it's a steel arch bridge with a rather chunky looking parapet, decked out in the patriotic Welsh colours of green, white and red.<br />
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A second look makes clear that it is, as the fabricator says on their website, <i>"a Vierendeel Construction with a Decorative Arch"</i>.<br />
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Opinions on this may vary. Some may note that it is just another in a long line of fake arch bridges, and hardly as egregious as <a href="https://structurae.net/en/structures/pont-de-l-aire-des-volcans-d-auvergne">some</a> <a href="https://bridgehunter.com/ca/sacramento/bh37310/">examples</a>. Others may wonder if the emphasis on superficiality over substance combines with the colouring to act as a sly post-modern comment upon the inherent hollowness of nationalism.<br />
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I'm not sure I would go that far, but I can say that I don't like it.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjBQi648IKxCa-2YI7w5zLHMAlZl1nPZWmB5L6ooQgugEfTAnNhW2UmWIDNiL60N9JV67BiR-tuRNiFeVkIyd0gsWrrnvAKiKLjDFL39DZ-8GVapdFk8iALAztwjo7ijyPeV6VJX7-I_uIr/s1600/LonLasOgwen1.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em; text-align: center;"><img border="0" data-original-height="1201" data-original-width="1600" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjBQi648IKxCa-2YI7w5zLHMAlZl1nPZWmB5L6ooQgugEfTAnNhW2UmWIDNiL60N9JV67BiR-tuRNiFeVkIyd0gsWrrnvAKiKLjDFL39DZ-8GVapdFk8iALAztwjo7ijyPeV6VJX7-I_uIr/s400/LonLasOgwen1.jpg" width="400" /></a></div>
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<b>Further information:</b><br />
<ul>
<li><a href="https://goo.gl/maps/DogCKu9ysWKvLcX59">Google maps</a></li>
<li><a href="http://www.dhwelding.com/project/lon-las-ogwen-bridge/">D. Hughes Welding</a> (including lots of construction photographs)</li>
</ul>
The Happy Pontisthttp://www.blogger.com/profile/15252272118786667592noreply@blogger.com0tag:blogger.com,1999:blog-6470543006314152962.post-91041634013032130902020-09-23T20:57:00.000+01:002020-09-23T20:57:00.175+01:00Welsh Bridges: 18. Britannia Bridge<div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjLYtAVod2Y6AGrBYnyxT2knBD5645C7VKvbmLgedn_oAZb4kEjsl8D7dN7GaO7kUsKo9Ysfty4AO37_VkfEVs8uGdsyNfNRxG_Im6pbSIbXMk10SSqRzsUvYA5yFYXtuZb4WDozsubnpL1/s1600/Britannia1a.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="882" data-original-width="1600" height="220" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjLYtAVod2Y6AGrBYnyxT2knBD5645C7VKvbmLgedn_oAZb4kEjsl8D7dN7GaO7kUsKo9Ysfty4AO37_VkfEVs8uGdsyNfNRxG_Im6pbSIbXMk10SSqRzsUvYA5yFYXtuZb4WDozsubnpL1/s400/Britannia1a.jpg" width="400" /></a></div>
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<a href="http://happypontist.blogspot.com/search/label/Thomas%20Telford" target="_blank">Thomas Telford</a> built two significant suspension bridges on the north Wales coastline: the <a href="https://happypontist.blogspot.com/2020/09/welsh-bridges-17-menai-suspension-bridge.html">Menai Suspension Bridge</a> (1819-1826), and <a href="https://en.wikipedia.org/wiki/Conwy_Suspension_Bridge" target="_blank">Conwy Suspension Bridge</a> (1822-1826). These formed part of a significant and much-needed improvement to the nation's highways. However, they were completed just four years before <a href="https://en.wikipedia.org/wiki/George_Stephenson" target="_blank">George Stephenson</a>'s <a href="https://en.wikipedia.org/wiki/Liverpool_and_Manchester_Railway" target="_blank">Liverpool and Manchester Railway</a> would kick start a very different transport revolution.</div>
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Roughly two decades after Telford did so for roads, it was George's son <a href="https://en.wikipedia.org/wiki/Robert_Stephenson" target="_blank">Robert Stephenson</a>'s turn to bring the railways to north Wales and Anglesey. He built two revolutionary bridges to span the exact same stretches of water as Telford: the <a href="https://en.wikipedia.org/wiki/Conwy_Railway_Bridge" target="_blank">Conwy Railway Bridge</a> (1846-1849), and the Britannia Bridge (1846-1850). And just as had been the case for Telford, Stephenson could not do it alone.</div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiDwWBuntAK6jaPUup8IbtRBT73Vp0wbXI3WOUfdPygRKvDM2zXnlzArX-iJRpUi6Rb_vTwgZHGb0fd3Gh0zPRHseOsrs3ADVLJQuSFt92h17PASrnKu8rUai2IJaCrZyicN5qzcbhFkYq3/s1600/Britannia7.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em; text-align: center;"><img border="0" data-original-height="926" data-original-width="1600" height="115" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiDwWBuntAK6jaPUup8IbtRBT73Vp0wbXI3WOUfdPygRKvDM2zXnlzArX-iJRpUi6Rb_vTwgZHGb0fd3Gh0zPRHseOsrs3ADVLJQuSFt92h17PASrnKu8rUai2IJaCrZyicN5qzcbhFkYq3/s200/Britannia7.jpg" width="200" /></a>The bridge across the Menai Strait was the most challenging element in the <a href="https://en.wikipedia.org/wiki/Chester_and_Holyhead_Railway" target="_blank">Chester and Holyhead Railway</a>, and decisions on how to span the Strait remained unresolved while designs progressed for other parts of the line. Some thought was given as to whether the Menai Suspension Bridge could be modified to carry trains, but the loads required for a railway far exceeded those imposed by the horsepower that initially crossed Telford's bridge.</div>
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As in Telford's time, consideration turned to building a new arch bridge, but the Admiralty insisted on the provision of full clearance for high-masted ships across the full width of the Menai. Having settled on an alignment that made use of Britannia Rock in the middle of the channel, Stephenson proposed a flat span structure, with girders supported from above by suspension chains. The bridge towers were designed and then constructed tall enough to support such chains, although in the end they were never installed.</div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgBMM5EmR4ud0tw7bZ-0gfJKWQ901Xi-0qY3tErO1pGP7snZG2UVXqm_wb8e1lX7HJNck9mYkVfkmdF6W-_ph1dOs4ga3zaJ7A4rXj4ie3yc1FXE2e-mmBsFMDpRGpfdSXXCQ6oAHO7bqGh/s1600/1024px-Civil_engineering%253B_the_Menai_box_girder_bridge._Engraving_by_Wellcome_V0024344.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="721" data-original-width="1024" height="281" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgBMM5EmR4ud0tw7bZ-0gfJKWQ901Xi-0qY3tErO1pGP7snZG2UVXqm_wb8e1lX7HJNck9mYkVfkmdF6W-_ph1dOs4ga3zaJ7A4rXj4ie3yc1FXE2e-mmBsFMDpRGpfdSXXCQ6oAHO7bqGh/s400/1024px-Civil_engineering%253B_the_Menai_box_girder_bridge._Engraving_by_Wellcome_V0024344.jpg" width="400" /></a></div>
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It seems that Stephenson conceived initially of a suspension bridge, and then sought a way in which it could be made sufficiently stiff to carry railway loads. He turned to <a href="https://en.wikipedia.org/wiki/William_Fairbairn" target="_blank">William Fairbairn</a> to investigate the feasibility of tubular stiffening girders, through which the railway tracks could run. Fairbairn rapidly came to the conclusion that the suspension chains would be too flexible, and should be dispensed with, but the less confident Stephenson kept provision for the chains until the bridge was complete.</div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgdDpq3QbpXebvb-nXDTFlJEZNiX0ElRZfWc1_ds5xKkcWP0z5I9kpfT6kmxj0ovrpJA4mFAYl2I84QwmO34K6zcvr2sey11DrHbUl8LjcGcxQ1dpWcKMuz-sxDfvFWR-8Gnm5p26BT-yBk/s1600/Britannia12.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em; text-align: center;"><img border="0" data-original-height="1600" data-original-width="1422" height="200" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgdDpq3QbpXebvb-nXDTFlJEZNiX0ElRZfWc1_ds5xKkcWP0z5I9kpfT6kmxj0ovrpJA4mFAYl2I84QwmO34K6zcvr2sey11DrHbUl8LjcGcxQ1dpWcKMuz-sxDfvFWR-8Gnm5p26BT-yBk/s200/Britannia12.jpg" width="177" /></a>Fairbairn undertook many experiments on tubular cross-sections, and in turn involved the mathematician <a href="https://en.wikipedia.org/wiki/Eaton_Hodgkinson" target="_blank">Eaton Hodgkinson</a> to analyse the experimental results. Stephenson's preferred girder design was for an elliptical cross-section, but Fairbairn soon determined that a rectangular section was more efficient. It rapidly became clear that buckling of the top flange of the girder was the key issue, a problem that was resolved by adopting a cellular upper flange to the girder, initially comprising two hollow circular tubes joined together, and later evolving into multiple cells side-by-side. </div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgNiHSLdXaIDPKoxrPE5tb_Mckv1Zz-GWvDu5_3S8RPo0NzNOIPFZAPyv9PPEsVDmGtqVqOxzxSmCwqbLDlserTPwon12d6aHifQkq49iFxW0Gzyk4c0wgwasD5JOQR3_sex9e0ezJ64hrI/s1600/Britannia8.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em; text-align: center;"><img border="0" data-original-height="1097" data-original-width="1379" height="158" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgNiHSLdXaIDPKoxrPE5tb_Mckv1Zz-GWvDu5_3S8RPo0NzNOIPFZAPyv9PPEsVDmGtqVqOxzxSmCwqbLDlserTPwon12d6aHifQkq49iFxW0Gzyk4c0wgwasD5JOQR3_sex9e0ezJ64hrI/s200/Britannia8.jpg" width="200" /></a>Fairbairn constructed a 75ft span model tubular girder to resolve the final details of the rectangular tube design. The side walls required internal stiffening, and in the final design both the top and bottom flanges were made cellular. Although Fairbairn's experiments had been on single spans, the bridge was built as a continuous girder, giving it additional strength and stiffness.</div>
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Some of the other key participants in the project included Stephenson's assistant <a href="https://en.wikipedia.org/wiki/Edwin_Clark_(civil_engineer)" target="_blank">Edwin Clark</a>, and Fairbairn's assistant Mr Blair, who was largely responsible for producing all the bridge's design drawings. After Fairbairn and Stephenson fell out in a dispute over recognition as being the true designer of the bridge, it was Clark who wrote the account setting out Stephenson's side of the story. Fairbairn published his own, and it seems generally to be regarded as the more honest version.</div>
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Credit is also due to architect <a href="https://en.wikipedia.org/wiki/Francis_Thompson_(architect)">Francis Thompson</a>, who designed the masonry elements in a vaguely Egyptian style, as well as several other works along the railway. Thompson later worked again with Stephenson on <a href="https://en.wikipedia.org/wiki/Victoria_Bridge_(Montreal)">Victoria Bridge, Montreal</a>, another tubular bridge, as part of the Grand Trunk Railway in Canada.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiVYitA7LE0zJmQh2c3ARkL5r4cHvrX7VDuQr1Sn2Cs4IBmOSC24uQ6_VWftcPgKCDnphXJn31_s8ePUBPxUVpXW9Fx_SABsOZuY5zVLdzh9GwR1pnZb4HOasT0qanDgL3Fd0mB1l9JMJlG/s1600/Britannia9.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em; text-align: center;"><img border="0" data-original-height="1201" data-original-width="1600" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiVYitA7LE0zJmQh2c3ARkL5r4cHvrX7VDuQr1Sn2Cs4IBmOSC24uQ6_VWftcPgKCDnphXJn31_s8ePUBPxUVpXW9Fx_SABsOZuY5zVLdzh9GwR1pnZb4HOasT0qanDgL3Fd0mB1l9JMJlG/s200/Britannia9.jpg" width="200" /></a>Four sculptural lions were installed, one at each corner of Britannia, Bridge,sculpted by <a href="https://en.wikipedia.org/wiki/John_Thomas_(sculptor)">John Thomas</a>, who also worked on the Palace of Westminster.</div>
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Hodgkinson had also fallen out with Fairbairn, essentially over the latter's willingness to extrapolate the results of his experimental work in the absence of a justifying mathematical theory. Around this time, Fairbairn began building many girder bridges with tubular (box) girders, but suitable theory was only just becoming available to practicing engineers. The sheer scale of the Britannia structure went well beyond what had been attempted previously - just as Telford's Menai Bridge had done a quarter of a century before.</div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjAYHt6iJNPjdNkEN4zJqhWYYxGUq-0Ux0wy7sQhr8ccpbrJTQ7dIoyxjHEZy1s7vLeAgQW4Rn_oLtBJ9lqfxn8rzp7BIOiGo_GowwpartPXFy-eJ9uPiZixFqXl8heOt9nIr82qYSNkTk1/s1600/Britannia4.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em; text-align: center;"><img border="0" data-original-height="1200" data-original-width="1600" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjAYHt6iJNPjdNkEN4zJqhWYYxGUq-0Ux0wy7sQhr8ccpbrJTQ7dIoyxjHEZy1s7vLeAgQW4Rn_oLtBJ9lqfxn8rzp7BIOiGo_GowwpartPXFy-eJ9uPiZixFqXl8heOt9nIr82qYSNkTk1/s200/Britannia4.jpg" width="200" /></a>The project innovated in many ways. The extensive reliance on wrought iron was pioneering, and the span was exceptional for a flat-span bridge. The range of experimental work relied upon was impressive, as was the idea for the cellular construction. Even the erection of the bridge required major innovation, with the girders lifted into place by jacking upwards with massive hydraulic jacks. The slots for the jacking process remain visible on the towers, and part of one jack can still be seen near the bridge on its south-west side.</div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjMVvB_bcfnnZMmIO0QIikj9KAIKvYrW2q_2ig307uEivmRWY_UQUSiOTS5AeCHqekF9Eei67xGOt2yoLUyt_WYjA0jqmaZvSJZ6y6YCim5BtZrfpIzNPxq9eEpBNWEjBnex0H8qhAx2qyf/s1600/Britannia13.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em; text-align: center;"><img border="0" data-original-height="1600" data-original-width="1201" height="200" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjMVvB_bcfnnZMmIO0QIikj9KAIKvYrW2q_2ig307uEivmRWY_UQUSiOTS5AeCHqekF9Eei67xGOt2yoLUyt_WYjA0jqmaZvSJZ6y6YCim5BtZrfpIzNPxq9eEpBNWEjBnex0H8qhAx2qyf/s200/Britannia13.jpg" width="150" /></a>Two million rivets were reported to be used, with workers having to squirm through the box cells to install many of them. This, more than anything else, determined the size of the cells used.</div>
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On 24 May 1847, while construction of the Britannia Bridge progressed, <a href="https://en.wikipedia.org/wiki/Dee_Bridge_disaster">one of Stephenson's other railway bridges collapsed</a>, killing five people. The bridge over the River Dee near Chester was constructed of three cast iron girder sections connected with wrought-iron link bars. It was a popular design at that moment of time, with at least thirty-four built prior to the Dee failure. Fairbairn had proposed in 1846 that Stephenson should use a wrought-iron tubular girder bridge across the Dee, but had been turned down.<br />
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This incident exposed Stephenson's lack of expertise as a structural engineer, and Fairbairn's views prevailed both at Britannia and more widely - he was involved in over 100 more tubular girder bridges (albeit predominantly with the girders sitting beside the tracks, rather than containing the tracks) within a 5 year period.</div>
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While the tubular girder was successful in the short-term for short and medium span bridges, it was not the optimal solution for larger structures, and the Britannia Bridge design would prove a dead-end. Before long, various forms of lattice-girder and truss bridges took over, although early lattice-girder railway bridges experienced their own problems. For more detail I can wholeheartedly recommend John Rapley's and Richard Byrom's books (see list of references below), both of which are excellent.</div>
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Britannia Bridge was bold, if not entirely beautiful, but I think there is a great deal to admire in its simplicity of line. It lasted 120 years until, on 23rd May 1970, a fire broke out, irreparably damaging the bridge's two tubular girders.</div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi2afVZJw2cPJXlH4Ejp99hcoMZpuvIgDkWo9AIHIInrh1_8hf_zBNuN5MEWYpWinv4SbyI85vzjbBIeIEs5Fr708OHCawH-yBRhOLHcQh93AIx4xjdcO3xdHCzQtsSGPbhqN5rpIY_f9Qv/s1600/Britannia2.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em; text-align: center;"><img border="0" data-original-height="900" data-original-width="1600" height="224" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi2afVZJw2cPJXlH4Ejp99hcoMZpuvIgDkWo9AIHIInrh1_8hf_zBNuN5MEWYpWinv4SbyI85vzjbBIeIEs5Fr708OHCawH-yBRhOLHcQh93AIx4xjdcO3xdHCzQtsSGPbhqN5rpIY_f9Qv/s400/Britannia2.jpg" width="400" /></a></div>
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The replacement bridge seen today was built between 1971 and 1974, with two main truss arch spans over the Menai Strait. Both Telford and Stephenson had considered arch bridges, and finally the navigational restrictions that had forced both into bolder and more innovative designs were no longer an issue.</div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi9Ux4108DqVycVeRJuh6XbGxb0elLnV6PuEQIGCCToaYAsuVm8bJ7zci2a3n3N8M7Us-Kzh286AshzbK-iz8HMYcGjPhlq9TBXwFM_pRYNHpqClLv98MglLZ7bs-zeThyphenhyphenkVwRP7DN1rK8c/s1600/Britannia6.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em; text-align: center;"><img border="0" data-original-height="1600" data-original-width="1201" height="200" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi9Ux4108DqVycVeRJuh6XbGxb0elLnV6PuEQIGCCToaYAsuVm8bJ7zci2a3n3N8M7Us-Kzh286AshzbK-iz8HMYcGjPhlq9TBXwFM_pRYNHpqClLv98MglLZ7bs-zeThyphenhyphenkVwRP7DN1rK8c/s200/Britannia6.jpg" width="150" /></a>The form of the present-day bridge, designed by Husband and Co. (merged into Mott, Hay and Anderson in 1989, now Mott MacDonald), owes a great deal to the challenges of safely dismantling the damaged tubular girders, as well as to the need to reinstate a railway line as quickly as possible. 10,500 tons of metalwork had to be removed, forming a load well in excess of the railway traffic that the replacement structure would carry, and the arches were therefore designed and sized primarily to act as support to the demolition operation. Once the tubes were safely and temporarily supported, railway services were reopened through one of the damaged tubes in January 1972. The tubes themselves were cut into short sections, and then hauled off the end of the bridge using small locomotives.</div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEijGf9GnohKthh2Ehd5LRCjZGypy3z7gg5uH5WqIStZMEXOx9mMAJOMLipyOuU9gRrJlraTsitMXfrzzURRwEDqdWLFVwWZbGETdBhecyMTu1xdVys9ROCQnmZGk8qPnyKvW4BDammESg4w/s1600/Britannia3.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em; text-align: center;"><img border="0" data-original-height="1600" data-original-width="1201" height="200" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEijGf9GnohKthh2Ehd5LRCjZGypy3z7gg5uH5WqIStZMEXOx9mMAJOMLipyOuU9gRrJlraTsitMXfrzzURRwEDqdWLFVwWZbGETdBhecyMTu1xdVys9ROCQnmZGk8qPnyKvW4BDammESg4w/s200/Britannia3.jpg" width="150" /></a>The bases of the towers were extended with small concrete skewbacks to carry stainless steel pins, which carry the entire load of the new bridge. The steelwork for the new arches was assembled by Cleveland Bridge four miles from the bridge, at Port Dinorwic, and floated into place on barges.<br />
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The spans were cantilevered outwards from the central tower, with adjustable tie bars passing through the tower to provide temporary support. Lifting gantries moved along the upper chord of the arch truss to lift each new truss unit into place, as can be seen in the construction photograph below (taken from a souvenir booklet about the bridge).<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiofqqJ4jgMFLpbA4BZG_acJtangeki32QDbG3ptgiqPd_9ZLFumT85RPvz8TICmSRqwALIf65es-kECraV9Y9fhqk4OTF02EYBKbGvZMqPXuaRwSpnafAfmku8oSzuR-LtrlYrfc0z62Iy/s1600/Construction01.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="834" data-original-width="1364" height="243" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiofqqJ4jgMFLpbA4BZG_acJtangeki32QDbG3ptgiqPd_9ZLFumT85RPvz8TICmSRqwALIf65es-kECraV9Y9fhqk4OTF02EYBKbGvZMqPXuaRwSpnafAfmku8oSzuR-LtrlYrfc0z62Iy/s400/Construction01.jpg" width="400" /></a></div>
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During construction, the arches each briefly formed a three-pinned arch before pre-load was jacked into the upper member to transform the whole system into a two-pinned arch.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi-OngA_eTkIYwbhp-C-f-kBihGqndkdqPwJk_2wkmlfCB5aaqCOcb6tOTHaJ2LOp1TkcqENP42RdmNKjjQQjuoLJDZVYfy7UDJ5JtMy6JMu38z4iFzMP6v71El_DiDNJE3Gi6rFkLYOWyx/s1600/Britannia10.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em; text-align: center;"><img border="0" data-original-height="1183" data-original-width="1600" height="147" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi-OngA_eTkIYwbhp-C-f-kBihGqndkdqPwJk_2wkmlfCB5aaqCOcb6tOTHaJ2LOp1TkcqENP42RdmNKjjQQjuoLJDZVYfy7UDJ5JtMy6JMu38z4iFzMP6v71El_DiDNJE3Gi6rFkLYOWyx/s200/Britannia10.jpg" width="200" /></a>Because the arches had capacity well in excess of railway loading, this created the opportunity to add a second deck to carry highway loading, and openings in the towers were enlarged to facilitate this. The railway bridge was finished in 1974 (albeit with only one deck carrying services, as railway traffic was much diminished), and the road deck eventually completed by Fairclough Civil Engineering and Fairfield Mabey in 1980.</div>
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The steelwork for the new railway bridge weighed less than half of Stephenson and Fairbairn's original wrought iron bridge, only 4,961 tons, although the road bridge (which is nearly twice as long as the rail bridge) incorporates another 4,338 tons of steel.<br />
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Although it is often noted that the ordinary observer prefers an arch bridge over any alternative, the modern bridge is, to my eyes, less loveable than the original. Partly this is because of the sheer quantity of truss bracing, and partly that the visual relationship between road and rail decks is uncomfortable. I think this is partly due to the sheer depth of the edge beams at railway level.<br />
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On the plus side, the history of the bridge is there to be seen. The excess tower height originally intended to carry suspension chains contributes to the support of the road deck and punctuates the span in a pleasing way (compare <a href="https://happypontist.blogspot.com/2014/06/sydney-harbour-bridge.html">Sydney Harbour Bridge</a>). The form of the arches betrays their origin as falsework for a demolition process. The preserved cross-section of tubular girder (accessible via a path leading to the south-west corner of the bridge) is well worth visiting. The masonry still looks excellent today, and the bridge's best-kept secret, the <a href="https://www.flickr.com/photos/63164772@N05/42268134434/in/photostream/">"cathedral" vaults</a> at each end, are still intact albeit normally inaccessible.</div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh5cBzE64XCrv7b2WHzYOE4eltlKLzKWyB8eMAJ9vFEfy2mlNtA7urfLjHO9mUQhvIaLEbvxMnooBo6XRbWSMcJ1C1FfI38wh0pVsrAzvBhNHhs0MqpBYGGbNuej0_EXAcsRLbDEkXxI_1c/s1600/Britannia11.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em; text-align: center;"><img border="0" data-original-height="748" data-original-width="1600" height="186" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh5cBzE64XCrv7b2WHzYOE4eltlKLzKWyB8eMAJ9vFEfy2mlNtA7urfLjHO9mUQhvIaLEbvxMnooBo6XRbWSMcJ1C1FfI38wh0pVsrAzvBhNHhs0MqpBYGGbNuej0_EXAcsRLbDEkXxI_1c/s400/Britannia11.jpg" width="400" /></a></div>
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<br />
<b>Further information:</b><br />
<ul>
<li><a href="https://goo.gl/maps/R1kDGqNnpCYD1YE56">Google maps</a></li>
<li><a href="https://en.wikipedia.org/wiki/Britannia_Bridge">Wikipedia</a></li>
<li><a href="https://structurae.net/en/structures/britannia-bridge">Structurae (1850)</a></li>
<li><a href="https://structurae.net/en/structures/britannia-bridge-1972">Structurae (1972)</a></li>
<li><a href="https://britishlistedbuildings.co.uk/300003674-britannia-tubular-bridge-pentir">British Listed Buildings</a></li>
<li><a href="https://coflein.gov.uk/en/site/34614/details/britannia-bridgebritannia-tubular-bridgepont-britannia-a55-bridge-menai-strait">Coflein</a></li>
<li><a href="http://www.engineering-timelines.com/scripts/engineeringItem.asp?id=42">Engineering Timelines (1850</a>)</li>
<li><a href="http://www.engineering-timelines.com/scripts/engineeringItem.asp?id=1415">Engineering Timelines (1974</a>)</li>
<li><a href="https://www.gracesguide.co.uk/Britannia_Bridge">Grace's Guide</a></li>
<li><a href="https://menaibridges.co.uk/">Menai Heritage</a></li>
<li><i><a href="https://rchs.org.uk/product/william-fairbairn-the-experimental-engineer/">William Fairbairn: The Experimental Engineer</a></i> (Byrom, 2017)</li>
<li><i><a href="https://menaibridges.co.uk/online-shop/online-shop-books/#walks">A Walking Guide to the Menai Strait Bridges</a></i> (Daimond and Kovach, 2015)</li>
<li><a href="https://www.icevirtuallibrary.com/doi/10.1680/ehah.2010.163.1.51"><i>Conway and Britannia Tubular Bridges: Stephenson's Team</i> </a>(Barr, ICE Engineering History and Heritage, 2010)</li>
<li><i><a href="http://www.arch.mcgill.ca/prof/sijpkes/aaresearch-2012/2013-structures/lattice-tube.pdf">Building Bridges and Boundaries: The Lattice and the Tube, 1820–1860</a></i> (Dreicer, <i>Technology and Culture</i>, 2010)</li>
<li><i><a href="https://www.amazon.co.uk/Britannia-Other-Tubular-Bridges-Built/dp/0752427539/ref=as_li_ss_tl?_encoding=UTF8&*Version*=1&*entries*=0&ie=UTF8&linkCode=ll1&tag=thehappon-21&linkId=938272a640d2a3ad6d13e24f84a62045&language=en_GB">The Britannia and other Tubular Bridges</a></i> (Rapley, 2003)</li>
<li><i><a href="https://www.researchgate.net/publication/321685289_The_Britannia_And_Conwy_Tubular_Bridges_Of_Robert_Stephenson">The Britannia And Conwy Tubular Bridges Of Robert Stephenson</a></i> (Chilton, IASS Symposium, 2000)</li>
<li><i><a href="https://www.icevirtuallibrary.com/doi/abs/10.1680/icien.1999.31738">Britannia Bridge: from concept to construction</a></i> (Ryall, ICE Civil Engineering, 1999)</li>
<li><a href="https://www.amazon.co.uk/Design-Paradigms-Histories-Judgment-Engineering/dp/0521466490/ref=as_li_ss_tl?dchild=1&keywords=Design+Paradigms:+Case+histories+of+error+and+judgement+in+engineering+(Petroski&qid=1600165647&s=books&sr=1-1-fkmr0&linkCode=ll1&tag=thehappon-21&linkId=67b248256cd8b5f59d5dd5e950714741&language=en_GB"><i>Design Paradigms: Case histories of error and judgement in engineering</i> (Petroski</a>, 1994)</li>
<li><i><a href="https://www.amazon.co.uk/Britannia-Bridge-Generation-Technological-Monographs/dp/0262180871/ref=as_li_ss_tl?dchild=1&keywords=Britannia+Bridge:+The+Generation+and+Diffusion+of+Technological+Knowledge+(Rosenberg+and+Vincenti&qid=1600165682&s=books&sr=1-1&linkCode=ll1&tag=thehappon-21&linkId=ccd2f478950fc821303ac7bb79c77440&language=en_GB">Britannia Bridge: The Generation and Diffusion of Technological Knowledge</a></i> (Rosenberg and Vincenti, 1978)</li>
<li><i>The Britannia Bridge</i> (Husband and Co.? souvenir booklet, 1978?)</li>
<li><i><a href="https://www.icevirtuallibrary.com/doi/abs/10.1680/iicep.1975.3883">Reconstruction of the Britannia Bridge</a></i> (Husband and Husband, ICE Proceedings, 1975)</li>
<li><i><a href="http://www.2d53.co.uk/britanniabridge/Fire%20Report.htm">Joint Report on a Fire in the Britannia Tubular Bridge, Menai Straits on Saturday May 23rd 1970</a></i> (Caernarvonshire and Anglesey Fire Brigades, 1970)</li>
<li><i><a href="https://archive.org/details/tubularandother00unkngoog">Tubular and other Iron Girder Bridges Particularly Describing the Britannia and Conway Tubular Bridges</a></i> (Drysdale Dempsey, 1850)</li>
<li><i><a href="https://archive.org/details/bub_gb_01xNAAAAcAAJ/page/n6/mode/2up">The Britannia and Conway Tubular Bridges Vol. 2</a></i> (Clark, 1850)</li>
<li><i><a href="https://archive.org/details/bub_gb_7D4DAAAAQAAJ/page/n4/mode/2up">The Britannia and Conway Tubular Bridges Vol. 1</a></i> (Clark, 1850)</li>
<li><i><a href="https://play.google.com/store/books/details/Edwin_Clark_General_Description_of_the_Britannia_a?id=_GsOAAAAYAAJ">General Description of the Britannia and Conway Tubular Bridges</a></i> (Clark, 1849)</li>
<li><i><a href="https://archive.org/details/anaccountconstr00fairgoog/page/n8/mode/2up">An account of the construction of the Britannia and Conway tubular bridges</a></i> (Fairbairn, 1849)</li>
</ul>
The Happy Pontisthttp://www.blogger.com/profile/15252272118786667592noreply@blogger.com1tag:blogger.com,1999:blog-6470543006314152962.post-60161123041438173272020-09-20T21:50:00.001+01:002020-09-20T21:50:00.488+01:00Welsh Bridges: 17. Menai Suspension Bridge<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgFbG6zJnor4sSB_UbSaZYVq0vD0we5R-R0eEiv4Vlf4PzQK8pxxhb5wD3wDZXvdDbFRgOf1aR5mkEJ5LU-UjWQIB8TFeB2XsPXwDf4jxAbiu-a30KNQOaWgz26FnQCCG7t1TBDVrmpv9yT/s1600/Menai1.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em; text-align: center;"><img border="0" data-original-height="900" data-original-width="1600" height="225" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgFbG6zJnor4sSB_UbSaZYVq0vD0we5R-R0eEiv4Vlf4PzQK8pxxhb5wD3wDZXvdDbFRgOf1aR5mkEJ5LU-UjWQIB8TFeB2XsPXwDf4jxAbiu-a30KNQOaWgz26FnQCCG7t1TBDVrmpv9yT/s400/Menai1.jpg" width="400" /></a></div>
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Where do you start when trying to write a simple blog post about a bridge like this? So much has already been written (see links at the end, which are selective and do ignore some of the more detailed publications)!<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhrRUsGaRo6Mx9BxUi-bE-QHg_0zaQoFKQ5ICTh49_7k4hTvIk19oBonH6_Me9SM0FKdpgVUlEjHRXzlrBl9x-K81rOjGr_-YBYYgjjgkhcj9BXZ7is5XAOd3LZvJSjKJMFzRcNaRQmxZLI/s1600/Menai2.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em; text-align: center;"><img border="0" data-original-height="900" data-original-width="1600" height="112" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhrRUsGaRo6Mx9BxUi-bE-QHg_0zaQoFKQ5ICTh49_7k4hTvIk19oBonH6_Me9SM0FKdpgVUlEjHRXzlrBl9x-K81rOjGr_-YBYYgjjgkhcj9BXZ7is5XAOd3LZvJSjKJMFzRcNaRQmxZLI/s200/Menai2.jpg" width="200" /></a>The first serious proposal for a bridge over the Menai Strait came in 1802, when John Rennie proposed a multi-span viaduct of masonry and cast iron. A few years later, in 1811, it was Thomas Telford's turn, presenting designs for either a multi-span cast iron viaduct similar to Rennie's or for a single cast-iron span. Neither of these ideas were adopted.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj-MXVRRpdGfo5o7SICKmZ9TUL9ZpG4CeuRwoUs2FE2E5POyPmNmcrIK2SrlZdXGQOfTHTyq_gNJVimioKEBxwkocuxP_U8eIK-Wy3d23sTqFUCD4TzjtvdU7jcc-qmi_EtOz2BiMA3lMVC/s1600/Menai3.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em; text-align: center;"><img border="0" data-original-height="1201" data-original-width="1600" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj-MXVRRpdGfo5o7SICKmZ9TUL9ZpG4CeuRwoUs2FE2E5POyPmNmcrIK2SrlZdXGQOfTHTyq_gNJVimioKEBxwkocuxP_U8eIK-Wy3d23sTqFUCD4TzjtvdU7jcc-qmi_EtOz2BiMA3lMVC/s200/Menai3.jpg" width="200" /></a>Telford revisited the site in 1818, and prepared plans for a suspension bridge instead. Construction work began on 10th August 1819, three years ahead of <a href="https://en.wikipedia.org/wiki/Conwy_Suspension_Bridge">Telford's suspension bridge at Conwy</a>. Both bridges were completed in the same year, 1826.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgPrjQcnRRwMyMlEd4uBg4TdTKgRDmqyUoVpLZikqfRz0zbKhJHi0N3ItYwqNN2G4CQ64d5l971cLBv_9kY7MtIxS2-g7-oXGeSwbCrs4xHvfgfZ-AOf1J1ypnt7nYpQovsPqpJvsVGSljn/s1600/Menai13.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em; text-align: center;"><img border="0" data-original-height="900" data-original-width="1600" height="112" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgPrjQcnRRwMyMlEd4uBg4TdTKgRDmqyUoVpLZikqfRz0zbKhJHi0N3ItYwqNN2G4CQ64d5l971cLBv_9kY7MtIxS2-g7-oXGeSwbCrs4xHvfgfZ-AOf1J1ypnt7nYpQovsPqpJvsVGSljn/s200/Menai13.jpg" width="200" /></a>The bridge at Menai became the longest bridge span in the world, its 577 feet length exceeding the 449 feet of Samuel Brown's <a href="http://happypontist.blogspot.com/2010/08/northumbrian-bridges-1-union-chain.html">Union Chain Bridge</a>, completed six years earlier in 1820. Brown's bridge had commenced construction only a few days before the Menai bridge, on 2nd August 1819, but was built much more quickly than Telford's bridge.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiXUP20dSanQpabxoS_cvirqJ0svNZmUBGRlYe2VjeHC9IwicQNRarNyXBFvufnmRLQo3XaTZ6RBhnzfY4vpxkBi0p4sPcrxy_Dt3bapZJoOrsFHwHbfiOBxVkUmpZlII8WOAX55iXD4vdG/s1600/Menai10.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em; text-align: center;"><img border="0" data-original-height="1600" data-original-width="900" height="200" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiXUP20dSanQpabxoS_cvirqJ0svNZmUBGRlYe2VjeHC9IwicQNRarNyXBFvufnmRLQo3XaTZ6RBhnzfY4vpxkBi0p4sPcrxy_Dt3bapZJoOrsFHwHbfiOBxVkUmpZlII8WOAX55iXD4vdG/s200/Menai10.jpg" width="112" /></a>Menai Suspension Bridge held the span record for 8 years before being overtaken by the 889ft <a href="https://structurae.net/en/structures/grand-pont-suspendu">Fribourg Suspension Bridge</a>, in October 1834, a month after Telford's death. It's maybe worth noting as a historical aside that the Union Chain Bridge's earlier record is attached to some degree of doubt: the 1430 <a href="https://en.wikipedia.org/wiki/Chushul_Chakzam">Chushul Chakzam</a> footbridge in Tibet may have been a very similar span, although records are poor.<br />
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The Menai Bridge's span was a remarkable achievement, and if it isn't Telford's finest bridge, I think it's the most substantial engineering challenge that he ever took on.<br />
<br />
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgEBJQOe5hFLoxli4jSO6019MRKooTSZkKcYLPad_dtAJH_bl0Z2xCU9rijk9NIRwuH0T-e1Js_jKrjDf3y2Q2htI3kXX_6Y7Qeypj8nKgEy4OEi8NPDsATGtDk1JFFviJvJGwxY7XvjZjW/s1600/Menai5.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em; text-align: center;"><img border="0" data-original-height="1200" data-original-width="1600" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgEBJQOe5hFLoxli4jSO6019MRKooTSZkKcYLPad_dtAJH_bl0Z2xCU9rijk9NIRwuH0T-e1Js_jKrjDf3y2Q2htI3kXX_6Y7Qeypj8nKgEy4OEi8NPDsATGtDk1JFFviJvJGwxY7XvjZjW/s200/Menai5.jpg" width="200" /></a>Telford had been looking at suspension bridge ideas since 1814, when he was commissioned to develop a proposal for a <a href="http://www.engineering-timelines.com/why/chainBridgesWales/chainBridges_03.asp">road bridge at Runcorn</a>. That design was for what would have been an astonishing 1000ft span, something that would not be achieved on any bridge until 1849. Telford proposed to form the Runcorn bridge's catenaries out of half-inch square iron bars, welded and bound together into sixteen "cables" each comprising 36 such bars. He arranged for extensive testing of the strength of iron to inform the design, and built a model suspension bridge 50ft long.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiBuErjjG6WpM0ge852RG5kEixWgA3bEtGHffmx7rs_vJO-JEC3Ayhdi8_sn3-2OR0SzQ1G-lWlYfvKDtg3Pgd8UePoabHM3rKgTlYIw0jRFNi2SO6cLs1hSE0IvENaI0r-9tcbi4Ld_W13/s1600/Menai4.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em; text-align: center;"><img border="0" data-original-height="1201" data-original-width="1600" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiBuErjjG6WpM0ge852RG5kEixWgA3bEtGHffmx7rs_vJO-JEC3Ayhdi8_sn3-2OR0SzQ1G-lWlYfvKDtg3Pgd8UePoabHM3rKgTlYIw0jRFNi2SO6cLs1hSE0IvENaI0r-9tcbi4Ld_W13/s200/Menai4.jpg" width="200" /></a>The promoters of the Runcorn crossing invited others to submit designs for review by Telford. The only submission to meet his approval was a suspension bridge proposal from Samuel Brown, who proposed catenaries comprising iron chains. Telford visited Brown's factory in February 1817, where he was driven across Brown's own model bridge, albeit quite a substantial model some 100ft in span. At the time, Brown was working with chains made from iron rods, as he was to use for the Union Chain Bridge, although he also developed chains made from flat iron plate.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgzLpcKEXWemBlIXPOn0ooTxZFxiencTVl-vq2D34vYAxpqb2TvAK2g_kp3Rnc0sgr8zx9V4OM9RgjCDqoASD4-UVn5PGs22q_zNnObiQENb4MJAc-AQtNzV-p5GRIkmx1Y5Y4rohdXkzXk/s1600/Menai8.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em; text-align: center;"><img border="0" data-original-height="1600" data-original-width="1200" height="200" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgzLpcKEXWemBlIXPOn0ooTxZFxiencTVl-vq2D34vYAxpqb2TvAK2g_kp3Rnc0sgr8zx9V4OM9RgjCDqoASD4-UVn5PGs22q_zNnObiQENb4MJAc-AQtNzV-p5GRIkmx1Y5Y4rohdXkzXk/s200/Menai8.jpg" width="150" /></a>The Runcorn bridge was never built, but when invited to develop the Menai crossing, Telford at first continued with his idea of square iron bars welded and bundled to form cables. Perhaps he was influenced by Brown's patenting his own chain bridge ideas in mid-1817. It was only later, as work proceeded on the masonry parts of the Menai bridge that Telford switched to flat-bar chains, supplied by <a href="https://en.wikipedia.org/wiki/William_Hazledine">William Hazledine</a>. There were to be sixteen chains in total, with four groups of four chains arranged vertically above each other; one group at each edge of the bridge, and two on the centreline of the roadway. There is a good image showing the original suspension arrangement at <a href="https://commons.wikimedia.org/wiki/Category:Menai_Suspension_Bridge#/media/File:Bangor,_View_on_Suspension_Bridge_(8571590364).jpg">Wikimedia Commons</a>.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgGML0VvWLvk56O5Y6M46bk3d-cLn8jy13tjknwA6bHr5rcuoWItBOr2cRdHeTvKEWWKfeEGgdE-xWHj6Jvj1fAhPL955tdAekysBJQIzpj1Nb-NV3LXPz6DWnSRbuu-hrD736DlRMC5nU3/s1600/Menai7.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em; text-align: center;"><img border="0" data-original-height="900" data-original-width="1600" height="112" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgGML0VvWLvk56O5Y6M46bk3d-cLn8jy13tjknwA6bHr5rcuoWItBOr2cRdHeTvKEWWKfeEGgdE-xWHj6Jvj1fAhPL955tdAekysBJQIzpj1Nb-NV3LXPz6DWnSRbuu-hrD736DlRMC5nU3/s200/Menai7.jpg" width="200" /></a>Incidentally, it is sometimes claimed that Telford sought permission from <a href="https://en.wikipedia.org/wiki/Sarah_Guppy">Sarah Guppy</a> to use her <a href="https://womenengineerssite.wordpress.com/2019/11/16/sarah-guppy-and-her-bridge-patent-no-3405-1811-guest-article-by-julia-elton/">1811 patent for suspension bridges</a>. Guppy's patent appears to have been for a catenary bridge, with the decking laid directly onto the suspension bridges, not for the type of bridge that Brown and Telford pursued. There seems to be <a href="https://cliftonbridge.org.uk/did-sarah-guppy-design-the-clifton-suspension-bridge/">little substance to this claim</a>, but Telford certainly did rely very much on the assistance of others. Examples include learning from Brown's success in pioneering the use of iron chains; Hazledine's manufacturing capabilities; Telford's right-hand engineer <a href="https://www.gracesguide.co.uk/William_Alexander_Provis">William Provis</a>; <a href="https://mathshistory.st-andrews.ac.uk/Biographies/Barlow/">Peter Barlow</a>'s advice on the strength of iron; and <a href="https://en.wikipedia.org/wiki/Davies_Gilbert">Davies Gilbert</a>'s understanding of the <a href="https://royalsocietypublishing.org/doi/10.1098/rsta.2014.0346">mathematics of the catenary</a>.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjmo6K_yLsk3VspgRPuak7fRz5e2L-3KDJNFKySZbAXGad91XKz0HbkZHNwRHnO2WtwDPH6LsXtPcHqME5pjxs4pJ1SLJHFxyXbq6UehB7tbV7FLLZNBBFClaq_FhZqfkTdenCUQUDhJmEY/s1600/Menai6.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em; text-align: center;"><img border="0" data-original-height="1200" data-original-width="1600" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjmo6K_yLsk3VspgRPuak7fRz5e2L-3KDJNFKySZbAXGad91XKz0HbkZHNwRHnO2WtwDPH6LsXtPcHqME5pjxs4pJ1SLJHFxyXbq6UehB7tbV7FLLZNBBFClaq_FhZqfkTdenCUQUDhJmEY/s200/Menai6.jpg" width="200" /></a>Telford's bridge encountered problems almost as soon as it was complete. Strong winds caused damage to the timber deck and to the hanger bars just one week after it opened. Remedial works were completed, but a storm in 1836 caused huge oscillations and significant damage, and then in 1839 another storm left the deck in ruins and the bridge impassable. Provis was employed to design a stronger, heavier deck.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg4mAxoGgNFuHArI2TdEcUIurjuFRPm41E-WRzHo0DkyqnRQZlWYyuGXZYlh1oZXIWoR8lK5bdbDeK-GCj4P5wZRDMXHjpLxWztQIZSRnfLTh2y44GF8J4gZ9pAuKVE07FgtasVk5oB50nb/s1600/Menai9.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em; text-align: center;"><img border="0" data-original-height="1600" data-original-width="900" height="200" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg4mAxoGgNFuHArI2TdEcUIurjuFRPm41E-WRzHo0DkyqnRQZlWYyuGXZYlh1oZXIWoR8lK5bdbDeK-GCj4P5wZRDMXHjpLxWztQIZSRnfLTh2y44GF8J4gZ9pAuKVE07FgtasVk5oB50nb/s200/Menai9.jpg" width="112" /></a>Issues with wind on suspension bridges were by no means unique to Menai. Similar issues occurred around the same time on Samuel Brown's <a href="https://www.bridgemeister.com/bridge.php?bid=388">South Esk Bridge</a> in Montrose, and wind-induced oscillation was also observed at <a href="http://happypontist.blogspot.com/2010/12/scottish-bridges-14-gattonside-bridge.html">Gattonside Bridge</a>. Telford had not been unaware of the issue, and before the bridge was complete he was reported to have considered stiffening the deck with trusses, deciding eventually that if ever required, they could be retrofitted. The Menai Bridge was a giant engineering prototype, and as with any experiment, its performance was never entirely foreseeable.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjXaSlblt-PFBW7Lpa8EyweHESjYxwFkLDaKZX7tH2SByxmIFxwdqKovbVotSmrNGyM5iKBin6QgIs9Y1-tDIrVh1ic5kXTfdOWUGnp1oRv69MuE6OY7IjQDPf0BJQpKOKLD_jBtw4yFw-O/s1600/Menai16.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em; text-align: center;"><img border="0" data-original-height="900" data-original-width="1600" height="112" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjXaSlblt-PFBW7Lpa8EyweHESjYxwFkLDaKZX7tH2SByxmIFxwdqKovbVotSmrNGyM5iKBin6QgIs9Y1-tDIrVh1ic5kXTfdOWUGnp1oRv69MuE6OY7IjQDPf0BJQpKOKLD_jBtw4yFw-O/s200/Menai16.jpg" width="200" /></a>The strengthened bridge lasted until 1893, when a new steel deck designed by <a href="https://en.wikipedia.org/wiki/Benjamin_Baker_(engineer)">Sir Benjamin Baker</a> was introduced, largely to resolve problems with the deteriorated state of the timber deck. Further investigation and remedial work took place on several occasions before a decision was made that the bridge could no longer safely carry the loads required.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh7RWE8ESCGPRGM65elHUDG68dV-PLWJyv5NP40JT3ADnqXA_QfYAPyur9V-09Tna5Q74AmgFWbivE48zGw5vpUm0wODdq5ClmlDompO-Hdx27Jg_0SWGf8L3_92PTUHiTUhURdw1lUeR7c/s1600/Menai15.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em; text-align: center;"><img border="0" data-original-height="1600" data-original-width="900" height="200" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh7RWE8ESCGPRGM65elHUDG68dV-PLWJyv5NP40JT3ADnqXA_QfYAPyur9V-09Tna5Q74AmgFWbivE48zGw5vpUm0wODdq5ClmlDompO-Hdx27Jg_0SWGf8L3_92PTUHiTUhURdw1lUeR7c/s200/Menai15.jpg" width="112" /></a>Between 1938 and 1940, the metal parts of the bridge were completely reconstructed, to a design prepared by Sir Alexander Gibb and Partners, and consultant <a href="http://www.engineering-timelines.com/who/Maunsell_G/maunsellGuy.asp">Guy Maunsell</a>. If the work had not already been underway, it's impossible to imagine it would have started once the Second World War began, given the quantity of steelwork involved and other demands for skilled labour. In any event the bridge was completed, but Maunsell was rapidly immersed in the war effort, turning his engineering skills towards <a href="http://www.engineering-timelines.com/who/Maunsell_G/maunsellGuy5.asp">sea forts</a> and the concept behind the floating <a href="https://en.wikipedia.org/wiki/Mulberry_harbour">Mulberry Harbours</a>. Due to the needs of wartime secrecy, his account of the Menai Bridge reconstruction was only published after the war had ended.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgyKobHHSZynhi7FdZBUclHdSvNBtfwykUWOUrkz1yl3F5rgsfQdeHCZTNnpoDAUXsHC_ZWYdzgfIoJF5wnHfiDilh5GiDc4KhGTETbnViQHLzXFF-RMB_JC0DDV-u6qXwIP0MelvVnpCke/s1600/Menai19.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em; text-align: center;"><img border="0" data-original-height="900" data-original-width="1600" height="112" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgyKobHHSZynhi7FdZBUclHdSvNBtfwykUWOUrkz1yl3F5rgsfQdeHCZTNnpoDAUXsHC_ZWYdzgfIoJF5wnHfiDilh5GiDc4KhGTETbnViQHLzXFF-RMB_JC0DDV-u6qXwIP0MelvVnpCke/s200/Menai19.jpg" width="200" /></a>The masonry approach spans, which are themselves impressive structures, were left unaltered. Works were undertaken on the upper towers to slightly widen the portals through which vehicles pass. The masonry Bridge Master's House at the southern end of the bridge had its upper parts rebuilt to accommodate replacement of the suspension chains.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiNQ0M7hW2lBvaJ5Wt_2-BrBBZ-RgQeszwJTq4Xlx0a-0csDY6CVtgEzZHFeNhx8YDfv-hAt9gWueo38q6ipWNuF7niIhhOpIC_WZV84a5gXmKqBFRFyAZQAtC9KIEcpfMp3Hgc6zk_9TgH/s1600/Menai17.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em; text-align: center;"><img border="0" data-original-height="900" data-original-width="1600" height="112" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiNQ0M7hW2lBvaJ5Wt_2-BrBBZ-RgQeszwJTq4Xlx0a-0csDY6CVtgEzZHFeNhx8YDfv-hAt9gWueo38q6ipWNuF7niIhhOpIC_WZV84a5gXmKqBFRFyAZQAtC9KIEcpfMp3Hgc6zk_9TgH/s200/Menai17.jpg" width="200" /></a>The suspension chain alterations included reconstruction of the anchorage elements hidden within tunnels at each end of the bridge. Temporary suspension cables were installed at the edges of the structure to relieve the load on the outer chains. The original sets of four chains directly above each other were replaced with sets of two chains directly above each other, with larger links in much stronger steel.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi4rDvYcFbrNC0Wni7WOr95hjRAxFLcg6psSPSeeqcnic51uf_TUplHr9XSbKqhc4xCkuiShPUrbXFQCb20siF8_farbWn9cBbkeRl1FT25Qp03vQPHcSrZfm5qMun7eKEFTrKTRHf686P7/s1600/Menai11.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em; text-align: center;"><img border="0" data-original-height="900" data-original-width="1600" height="112" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi4rDvYcFbrNC0Wni7WOr95hjRAxFLcg6psSPSeeqcnic51uf_TUplHr9XSbKqhc4xCkuiShPUrbXFQCb20siF8_farbWn9cBbkeRl1FT25Qp03vQPHcSrZfm5qMun7eKEFTrKTRHf686P7/s200/Menai11.jpg" width="200" /></a>A new deck was constructed below the existing deck, to allow traffic to continue to use the bridge during the works. The existing deck was then removed (one lane at a time), allowing traffic to drive up and down ramps onto the lower deck. Once this stage was complete, the new deck was gradually raised into its final position. The original centre chains were removed entirely, with the only real evidence today of their existence being the empty slots in the face of the former Bridgemaster's House. The new edge trusses were then completed, considerably enhancing the load carrying capacity of the bridge.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiME2cjO0YpcLXptlAFRlOSkg3pvRlYoCtsGitYxkE2qk7Zz_uJhI_-BPHuqh_bBB7w_QkWsXH9ILzZJ3GUtb13yiXvlWQ9xa9_85bD_7xrDeHUXIssswZ2QDxvIoWmjgu77wPgcYVVedS3/s1600/Menai14.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em; text-align: center;"><img border="0" data-original-height="1600" data-original-width="900" height="200" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiME2cjO0YpcLXptlAFRlOSkg3pvRlYoCtsGitYxkE2qk7Zz_uJhI_-BPHuqh_bBB7w_QkWsXH9ILzZJ3GUtb13yiXvlWQ9xa9_85bD_7xrDeHUXIssswZ2QDxvIoWmjgu77wPgcYVVedS3/s200/Menai14.jpg" width="112" /></a>I doubt that casual visitors to the bridge see it as anything other than Telford's structure. The profile remains the same, including the strange back-span arrangements where the chains are anchored directly down into the approach viaducts with hanger bars. Given the over-riding need to enhance the traffic capacity of the highway, the reconstruction was a relatively sensitive project. Even retaining chain catenaries was a technologically unusual choice in the mid-20th century: nobody was still building chain bridges at that point in time.<br />
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The trusses were foreseen by Telford, and don't mar the overall appearance of the structure, although the tacked-on cantilever footways are narrow and the new parapets feel over-tall. The detailing of the footway widening on the approach viaducts gives the impression that it was always there.<br />
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The bridge now provides one of the best viewpoints in the vicinity, and is one of the UK's most significant engineering landmarks. As with many such large bridges, it has come to define the character of the Menai Strait, visually structuring the way that visitors experience the area as well as remaining a key transport link.<br />
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Another bridge was built in 1850 to carry the railway across the Strait (later converted to become the main highway in the 1970s), and plans are under consideration for a <a href="https://gov.wales/a55-3rd-menai-crossing-0">third crossing</a>. As with the Forth in Scotland, the prospect of a "family" of bridges is enticing, although it is too early to tell whether the new plans will be as visually successful.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg_7LmpCdXlmKVQJo6xIw0POgyrNZVQnhZkfKyy2fDE7iMIXbzNushPGxWpcknY0BHBFlZONiLtdKRcWUhh5D7Sd-huHHxxqskPKo3n-TJ0qE3hVYm0CBw86nQ8Gi7owIAixe5gSQUBRk7f/s1600/Menai12.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="900" data-original-width="1600" height="225" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg_7LmpCdXlmKVQJo6xIw0POgyrNZVQnhZkfKyy2fDE7iMIXbzNushPGxWpcknY0BHBFlZONiLtdKRcWUhh5D7Sd-huHHxxqskPKo3n-TJ0qE3hVYm0CBw86nQ8Gi7owIAixe5gSQUBRk7f/s400/Menai12.jpg" width="400" /></a></div>
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<b>Further information:</b><br />
<ul>
<li><a href="https://goo.gl/maps/7ZJs5iv1HRMuHQdq8">Google maps</a></li>
<li><a href="https://en.wikipedia.org/wiki/Menai_Suspension_Bridge">Wikipedia</a></li>
<li><a href="https://structurae.net/en/structures/menai-suspension-bridge">Structurae</a></li>
<li><a href="https://britishlistedbuildings.co.uk/300018572-menai-suspension-bridge-menai-bridge#.X05UmchKiUl">British Listed Buildings</a></li>
<li><a href="http://www.engineering-timelines.com/scripts/engineeringItem.asp?id=88">Engineering Timelines</a></li>
<li><a href="https://coflein.gov.uk/en/site/43063/details/menai-suspension-bridge">Coflein</a></li>
<li><a href="https://www.gracesguide.co.uk/Menai_Suspension_Bridge">Grace's Guide</a></li>
<li><a href="https://www.bridgemeister.com/bridge.php?bid=382">Bridgemeister</a></li>
<li><a href="https://menaibridges.co.uk/">Menai Heritage</a></li>
<li><i><a href="https://happypontist.blogspot.com/2020/01/some-recent-books-about-bridges.html">Menai Suspension Bridge: The First 200 Years</a></i> (Daimond, 2019)</li>
<li><i><a href="https://menaibridges.co.uk/online-shop/online-shop-books/#walks">A Walking Guide to the Menai Strait Bridges</a></i> (Daimond and Kovach, 2015)</li>
<li><i><a href="https://royalsocietypublishing.org/doi/10.1098/rsta.2014.0346">An amateur's contribution to the design of Telford's Menai Suspension Bridge: a commentary on Gilbert (1826) ‘On the mathematical theory of suspension bridges’</a></i> (Calladine, Phil. Trans. R. Soc. A, 2015)</li>
<li><i><a href="https://www.icevirtuallibrary.com/doi/10.1680/ehah.2012.165.1.9">Menai Suspension Bridge: a history of maintenance and repair</a></i> (Day, ICE Engineering History and Heritage, 2012)</li>
<li><i><a href="https://www.icevirtuallibrary.com/doi/10.1680/cien.2007.160.5.26">Telford's Menai and Conwy suspension bridges, Wales</a></i> (Day, Proceedings of the ICE, 2007)</li>
<li><i><a href="https://www.princeton.edu/~civ102/labs/billington_article.pdf">Performance of the Menai Straits Bridge Before and After Reconstruction</a></i> (Billington and Deodatis, <i>Restructuring: America and Beyond</i>, American Society of Civil Engineers, 1995)</li>
<li><i><a href="https://menaibridges.co.uk/online-shop/online-shop-books/#secret">The Secret Bridge</a></i> (Richards, 1991)</li>
<li><i><a href="https://www.tandfonline.com/doi/abs/10.1179/tns.1977.007">Menai Bridge (1818–1826) and its influence on Suspension Bridge Development</a></i> (Paxton, Transactions of the Newcomen Society, 1977)</li>
<li><i><a href="https://www.e-periodica.ch/digbib/view?pid=bse-cr-001:1948:3::48#666">Preservation of the Menai Suspension Bridge</a></i> (Maunsell, IABSE 3rd Congress, 1948)</li>
<li><i><a href="https://www.icevirtuallibrary.com/doi/abs/10.1680/ijoti.1946.13922">Menai Bridge Reconstruction</a></i> (Maunsell, Journal of the ICE, 1946)</li>
<li><i><a href="https://www.icevirtuallibrary.com/doi/10.1680/lott.61163.217">Life of Thomas Telford: The Menai Bridge</a></i> (Telford, 1838)</li>
<li><i><a href="https://archive.org/details/amemoirsuspensi01drewgoog/page/n64/mode/2up">A Memoir of Suspension Bridges</a></i> (Drewry, 1832)</li>
<li><i><a href="https://www.e-rara.ch/zut/doi/10.3931/e-rara-14845">An Historical and Descriptive Account of the Suspension Bridge Constructed over the Menai Strait in North Wales</a></i> (Provis, 1828)</li>
<li><i><a href="https://www.e-rara.ch/zut/wihibe/content/titleinfo/18311163">Description of the iron bridges of suspension erected over the strait of Menaï, at Bangor; over the river Conway, in North Wales; and over the river Thames, at Hammersmith; with views </a></i>(Cumming, 1828)</li>
<li><i><a href="https://menaibridges.co.uk/online-docs/Pring-1827.pdf">Particulars of the Grand Suspension Bridge erected over the Straits of Menai</a></i> (Pring, 1826)</li>
</ul>
The Happy Pontisthttp://www.blogger.com/profile/15252272118786667592noreply@blogger.com0tag:blogger.com,1999:blog-6470543006314152962.post-20199016684723371792020-09-16T22:01:00.000+01:002020-09-16T22:01:01.033+01:00Manchester Bridges: 24. Brabyns Park Bridge, MarpleNow here's a tale of woe.<br />
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<a href="http://www.natgould.org/nathaniel_wright_1762-1818">Nathaniel Wright</a> exemplified the manner in which the industrial revolution wrought huge changes on British Society at the end of the 18th and beginning of the 19th century. He made his fortune from coal mining in Derbyshire, and associated closely with other entrepreneurs such as <a href="https://oldknows.com/oldknow.html">Samuel Oldknow</a>, who was the main driver behind construction of the Peak Forest Canal, connecting the Derbyshire coal mines through to Manchester.<br />
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In 1800, while the Canal was just finishing work on Benjamin Outram's <a href="https://happypontist.blogspot.com/2020/01/manchester-bridges-23-marple-aqueduct.html">Marple Aqueduct</a>, Wright purchased the Brabyns Hall estate nearby. The estate lies immediately to the east of the Peak Forest Canal, occupying the land between the canal and the River Goyt. As one improvement to the estate, Wright commissioned Salford Iron Works to construct a bridge across the river, providing access to and from nearby Compstall village. The Salford firm's engineers James Bateman and Thomas Sherratt had previously in 1795 supplied a pumping engine for one of Wright's collieries.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiYtAaGibAEABbfLgpid04Bd1FQckcjtiPpQKqY9pwsEykQKsWqpr1YLwTZ6sRKh8-KfPEhaVVRfO0-Pq8QLEvKNjmY4bcaOh4o7YBBnzu9tdNuNNyYGRMMpYcZ1ZctmW0B0YmcGJfqGcfv/s1600/Brabyn1.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1201" data-original-width="1600" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiYtAaGibAEABbfLgpid04Bd1FQckcjtiPpQKqY9pwsEykQKsWqpr1YLwTZ6sRKh8-KfPEhaVVRfO0-Pq8QLEvKNjmY4bcaOh4o7YBBnzu9tdNuNNyYGRMMpYcZ1ZctmW0B0YmcGJfqGcfv/s400/Brabyn1.jpg" width="400" /></a></div>
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The new bridge was in the form of a cast iron arch, possibly the first such bridge in this part of England. The design was broadly patterned after Thomas Telford's 1797 <a href="https://www.gracesguide.co.uk/Cound_Arbour_Bridge">Cound Arbour Bridge</a>, with three cast iron arch ribs, each with a series of iron circles filling the spandrels. Variations on this theme were common, another example being the 1810 <a href="https://en.wikipedia.org/wiki/Tickford_Bridge">Tickford Bridge</a>, but Telford had moved on, using the more rational diamond-pattern spandrels in his 1814 <a href="http://happypontist.blogspot.com/2012/08/scottish-bridges-40-craigellachie-bridge.html">Craigellachie Bridge</a>, for example.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiUnGW0Wa-gYdJYPYrsp9_iXOfLvpqgeOjdcA77XgW84vioi5sTp6XioEqurq6dPIlyO4f2kIxzuU0CtY0wdV1N2BTG-sAL1Rlr_rKaPisV260aNI9x6SUIxQNgCnk1S5onSEtOZNA6GFZs/s1600/Brabyn4.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="1600" data-original-width="1201" height="200" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiUnGW0Wa-gYdJYPYrsp9_iXOfLvpqgeOjdcA77XgW84vioi5sTp6XioEqurq6dPIlyO4f2kIxzuU0CtY0wdV1N2BTG-sAL1Rlr_rKaPisV260aNI9x6SUIxQNgCnk1S5onSEtOZNA6GFZs/s200/Brabyn4.jpg" width="150" /></a>The bridge is decorated with the date and name of its maker, and the lightweight iron parapets feature an ornamental "W" in the middle, for the owner Wright, who died five years after the bridge's completion, in 1818.<br />
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So far as is known, the Brabyns Park span is the only bridge to have been built by the Salford Iron Works. It spans approximately 14m (46ft) and is 2.7m (9ft) wide. The central rib was cast in two halves, joined in the middle. The external ribs were cast in six pieces, with each half subdivided into three parts: an upper rib, a lower rib, and the circular spandrel elements. The arch ribs were stabilised by tie bars at their lower level, and by cross-bracing at the upper level. The original decking comprised timber planks.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhus6NYngLHItYcrP3umezBznFsNevBIGH2EzpcWf7EAgmnTSAgepXAzL0NFN5OCYAarZp_BJ38EBDQg2nUOGo6MzUyU27J62LB5nm4Mafzxbrzvw5h07UNXxhyIrUj8B1ROd2ty7XJBkWq/s1600/Brabyn3.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="979" data-original-width="1306" height="149" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhus6NYngLHItYcrP3umezBznFsNevBIGH2EzpcWf7EAgmnTSAgepXAzL0NFN5OCYAarZp_BJ38EBDQg2nUOGo6MzUyU27J62LB5nm4Mafzxbrzvw5h07UNXxhyIrUj8B1ROd2ty7XJBkWq/s200/Brabyn3.jpg" width="200" /></a></div>
In 1991, a structural assessment of the bridge labelled it dangerous, and a "temporary" bailey bridge was installed directly above it, remaining there until 2007, when the bridge was finally refurbished, following <a href="http://www.marple-uk.com/ironbridge/ironbridge0.htm">a lengthy campaign</a>. Photographs of the bridge <a href="https://visitmarple.co.uk/photos/thumbnails.php?album=52&page=1">taken in 2007</a> immediately prior to refurbishment show the bridge to be horribly neglected, although how much of that was due to the difficulty of maintaining it with the bailey bridge in the way is hard to tell.<br />
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The bridge is Grade II Listed, but it was a lengthy battle to secure Heritage Lottery funding for its restoration, and then to agree exactly what works would be carried out. A design by engineers Scott Wilson Kirkpatrick (now <a href="https://en.wikipedia.org/wiki/Scott_Wilson_Group">submerged into AECOM</a>) was eventually accepted after much debate.<br />
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In 2003, the campaigners had <a href="http://www.marple-uk.com/ironbridge/report.pdf">commissioned a report</a> by local engineering lecturer and historic bridge specialist Tom Swailes. According to the report, the main issue with the bridge when it was closed in 1991 was the condition of the timber decking. Swailes took the view that:<br />
<blockquote class="tr_bq">
<i>"Future loads on the bridge will be no greater than the loads that it safely carried for 178 years. It is interesting to apply modern computer-based structural analysis techniques to old structures, but the results of such theoretical analyses must almost always be disbelieved unless verified by tests on the structure itself."</i></blockquote>
The subsequent involvement of "proper" consulting engineers seems to have been a curse. The <a href="http://www.marple-uk.com/ironbridge/">designer's drawings</a> proposed significant alterations to the bridge, over and above what may have been required for simple restoration. As Swailes noted in his report, despite its neglect the bridge had stood the test of time.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgXjIBkrXJrlKO3JxBE5bRpczLVBY74vgCkqlimcbf-VzY3yKBIpXnuIwkf2Y8t3h11-UiZaSMXJCbqT-nWgyUyG2GeW_lXL3D0Ht7VsJJFXXsKp3k9n5oKhrlHSvKdJ3gEzXRPALQzjdAB/s1600/Brabyn2.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="1201" data-original-width="1600" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgXjIBkrXJrlKO3JxBE5bRpczLVBY74vgCkqlimcbf-VzY3yKBIpXnuIwkf2Y8t3h11-UiZaSMXJCbqT-nWgyUyG2GeW_lXL3D0Ht7VsJJFXXsKp3k9n5oKhrlHSvKdJ3gEzXRPALQzjdAB/s200/Brabyn2.jpg" width="200" /></a>That was clearly not enough. The main structural alterations involved the bonding of steel plates to the central arch rib, the renewal of corroded bracing elements and the addition of new transverse bracing between the arches. These have relatively minimal impact on the appearance of the bridge, and you may struggle to see them on my photographs. In any event the underside of the bridge is not seen by most people, and is difficult to view even from the river bank.<br />
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The larger issues for the engineers (or for the technical approval authority at Stockport Council, perhaps), were the presence of a gas main, a small water main, and electric cables, which seem to have been previously laid on top of the deck planks; and the height and strength of the existing parapet railings, which were now judged to be inadequate.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjDQnTbnOtmu4aw7y2bhQ2_gppJBak8gLoZYvqHz0dSvcYJBgSZ4XAgDcwVfoctnMO2qZBhxXo3fekR8JLtrccGuXRBoMYUBNPFRXEQ_H2Tf2lcgk6pi0L-9ah1ULuxHUAovttu1ivNSsK2/s1600/Brabyn5.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="1201" data-original-width="1600" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjDQnTbnOtmu4aw7y2bhQ2_gppJBak8gLoZYvqHz0dSvcYJBgSZ4XAgDcwVfoctnMO2qZBhxXo3fekR8JLtrccGuXRBoMYUBNPFRXEQ_H2Tf2lcgk6pi0L-9ah1ULuxHUAovttu1ivNSsK2/s200/Brabyn5.jpg" width="200" /></a>Measuring from the engineer's drawings, the original parapets are approximately 1.15m tall (although it will have been less when fill material had been piled onto the bridge decking to cover the gas main). This could not possibly do, the parapets had to comply with modern standards and be 1.4m tall (the modern requirement for cyclists). The solution to this, and also to accommodating the utilities, was to install new parapets connected to steel hollow sections sitting entirely on top of the existing bridge, with the hollow sections also used to contain the utilities.<br />
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The campaigners were evidently not very happy. On <a href="http://www.marple-uk.com/ironbridge/">their website</a> they indicated their regret:<br />
<blockquote class="tr_bq">
<i>"This means that in the future, perhaps with technological improvement or an enlightened approach to safety standards, or a combination of both, the modern intervention could all be removed and the old bridge will be revealed intact underneath."</i></blockquote>
No such technological improvement was ever needed: simply an "enlightened approach" that recognised that an existing historic structure could be considered to be perfectly acceptable whether or not it complied with modern standards. Nobody is going around rebuilding ancient castles (or installing 1.4m tall balustrades on the battlements) simply because the original builders couldn't foresee the stupidity of 21st century compliance-drive engineering culture.<br />
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Quite what the local planning authority, or English Heritage (now Historic England), thought is difficult to say. They certainly should have demanded that the engineers think again. Reading through the excellent restoration campaign website, one thing that jumps out at me is the absence of any mention of a specialist conservation engineer or conservation architect. The result, in my opinion, was deeply unfortunate.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgZPf9SCZ3kQFk_TVSFY58RIkc0SsXcM3EmU8FyPIu6Y7lsgHLVwSns4a4P2jEU2UH1R0AMxqHTOVRMNO-oakBBGXWx7xMhpfZF351y1ACMc0jh-uG5OsBAyXNrwZG3AMsEWLmrBqOhM_Hi/s1600/Brabyn6.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em; text-align: center;"><img border="0" data-original-height="1026" data-original-width="1600" height="128" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgZPf9SCZ3kQFk_TVSFY58RIkc0SsXcM3EmU8FyPIu6Y7lsgHLVwSns4a4P2jEU2UH1R0AMxqHTOVRMNO-oakBBGXWx7xMhpfZF351y1ACMc0jh-uG5OsBAyXNrwZG3AMsEWLmrBqOhM_Hi/s200/Brabyn6.jpg" width="200" /></a>The new parapets are painted a different colour to the original bridge, with a view to disguising them when the bridge is viewed from a distance. I don't think it succeeds: the elevation of the bridge is intact but the parapets are hard to miss. Seen from the perspective of crossing the bridge, the visual impact is much worse, essentially ruining what was a fine and historic structure. Reaching over the new parapets to push against the old ones, it seemed to me that the original parapets were quite strong enough.<br />
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The difficulty with hoping that this can be put right in the future is that not only was the opportunity lost at the time when funding was available, but that so much of the funding was seemingly unnecessary. It is perhaps unfair to criticise those involved when not in possession of all the information that they had, but at best the treatment of the Brabyns Park bridge is a crying shame, and at worst it's the inevitable but disastrous outcome of foolishness and incompetence.<br />
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<b>Further information:</b><br />
<ul>
<li><a href="https://goo.gl/maps/3K8uH68zJtD75VwK9">Google maps</a></li>
<li><a href="https://www.gracesguide.co.uk/Brabyns_Park_Iron_Bridge">Grace's Guide</a></li>
<li><a href="https://britishlistedbuildings.co.uk/101242462-iron-bridge-marple-north-ward#.X0zyIMhKg2w">British Listed Buildings</a></li>
<li><i><a href="http://www.marple-uk.com/ironbridge/ironbridge20.htm">A Brief History of the Park, the Iron Bridge and the People Involved in its Construction</a></i> (Whittaker and Clarke, 2006)</li>
<li><a href="http://www.marple-uk.com/ironbridge/ironbridge0.htm">Bridge restoration campaign website</a> (well worth a visit - hugely informative!)</li>
<li><a href="https://visitmarple.co.uk/photos/thumbnails.php?album=52&page=1">Bridge restoration photographs</a></li>
</ul>
The Happy Pontisthttp://www.blogger.com/profile/15252272118786667592noreply@blogger.com0tag:blogger.com,1999:blog-6470543006314152962.post-7000410187720486722020-09-13T21:38:00.000+01:002020-09-13T21:38:00.261+01:00Derbyshire Bridges: 5. Headstone Viaduct<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEghDOLyuTgifR2b-5v82G6f4JWY0B8CcpiQ5wG7GsN0tZgNXtnayfSMgMWN9h7o2wxDKSkQYq1tH8KiC9CtqMeNAmr0yIABaX3cDdiPCzYJcMeswHHJbwgCFRJ1HZLfWPIfOxuLEUHuajR3/s1524/MonsalDaleSRWyatt.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="1524" data-original-width="925" height="200" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEghDOLyuTgifR2b-5v82G6f4JWY0B8CcpiQ5wG7GsN0tZgNXtnayfSMgMWN9h7o2wxDKSkQYq1tH8KiC9CtqMeNAmr0yIABaX3cDdiPCzYJcMeswHHJbwgCFRJ1HZLfWPIfOxuLEUHuajR3/w198-h328/MonsalDaleSRWyatt.jpg" width="120" /></a></div>
This will be my final "Derbyshire Bridge" for now, and this one is a well-known historic classic, Headstone Viaduct, also often known as Monsal Dale Viaduct. It is the star of a famous <a href="https://en.wikipedia.org/wiki/London,_Midland_and_Scottish_Railway">London Midland and Scottish Railway</a> poster used to attract tourism to the <a href="https://en.wikipedia.org/wiki/Peak_District">Peak District</a>, depicting a deservedly spectacular location (albeit with some artistic license!)<br />
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The viaduct was completed in 1863 as part of the Midland Railway company's <a href="http://manchester%2C%20buxton%2C%20matlock%20and%20midland%20junction%20railway/">Manchester, Buxton, Matlock and Midland Junction Railway</a>. This railway has a long and complex history, which (if so inclined) you are better off reading at Wikipedia than I am repeating in any detail here. Suffice to say that the route connected Derbyshire to Manchester through the hilly terrain of the Peak District, and substantial civil engineering works were required.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhW_4EPHtHpjLzw2gRQ8PG0BiETbNTETKeBBr_S8bM-mAnQ1KsOWQzmj-e78UAqIYyk1IbyVLz2OcyYvh99BSpUycR1c1WhNe_4UzrXuzVnm_HVxzvNUqJAZgvNuI1KoHX1zBlwEjWFwUjc/s1600/Headstone1.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="900" data-original-width="1600" height="225" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhW_4EPHtHpjLzw2gRQ8PG0BiETbNTETKeBBr_S8bM-mAnQ1KsOWQzmj-e78UAqIYyk1IbyVLz2OcyYvh99BSpUycR1c1WhNe_4UzrXuzVnm_HVxzvNUqJAZgvNuI1KoHX1zBlwEjWFwUjc/s400/Headstone1.jpg" width="400" /></a></div>
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It seems a wonder now that there were ever funds available to build a railway through such difficult terrain, necessitating not only major viaducts but a number of substantial tunnels. Perhaps it is worth imagining what the nature of the highways of the time must have been, for this to have been an attractive alternative.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhXKmTCbMF7ZbKV53tYOSw3D24EPojlCwpE52o2lU5xtIeszsqCczuTixV6nbTTM61ef0LybMBfb5Vz6eOhFKQ4leM13TpaQ8HJPxAmcljGSwhpuNksa9cBRB2mLn62Nwe2jSLiswB261OU/s1600/Headstone6.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="1102" data-original-width="1469" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhXKmTCbMF7ZbKV53tYOSw3D24EPojlCwpE52o2lU5xtIeszsqCczuTixV6nbTTM61ef0LybMBfb5Vz6eOhFKQ4leM13TpaQ8HJPxAmcljGSwhpuNksa9cBRB2mLn62Nwe2jSLiswB261OU/s200/Headstone6.jpg" width="200" /></a>The viaduct has five arches each spanning 50 feet (15.5m), and is roughly 25m tall. It originally carried two railway tracks, emerging from a tunnel in the steep hillside to the east and then passing along the flank of another hill to the west.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgMSKhykYTZxZbikBm9c7EPmJGGAxhQYavT1e-fQ0vd4mtwKYsOuy0Ld1jXmkWnZsWneQOZAU6EOtBUNF9NUISuoeZ5e7Hb0msa6aD7mwLD9gkSVzWy4nfNSBr4Jpgsvukecvjv2fmUMISc/s1600/Headstone3.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="826" data-original-width="1469" height="111" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgMSKhykYTZxZbikBm9c7EPmJGGAxhQYavT1e-fQ0vd4mtwKYsOuy0Ld1jXmkWnZsWneQOZAU6EOtBUNF9NUISuoeZ5e7Hb0msa6aD7mwLD9gkSVzWy4nfNSBr4Jpgsvukecvjv2fmUMISc/s200/Headstone3.jpg" width="200" /></a>The railway was closed in 1968, and the route was converted to the <a href="https://en.wikipedia.org/wiki/Monsal_Trail">Monsal Trail</a> for cyclists and walkers in 1981. The closest you can come now to reliving the steam train experience would be to hurtle westwards on a bicycle at speed from the tunnel mouth into the open air, taking in the views with a sense of astonishment and relief.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEioHkggWyRLbwkyUbylxvhXPYkzjxZn98lVpsEAGbfCS07gaH2thGRhgBbF3Ex9NllL6Tg17-uY-3b9vU2laSfMViC3XnmgJuE7QJDq2BA-IcW4CXiHWJvppRcc0Ms4_OT6DCZ2LvcXS47t/s1600/Headstone5.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="1201" data-original-width="1600" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEioHkggWyRLbwkyUbylxvhXPYkzjxZn98lVpsEAGbfCS07gaH2thGRhgBbF3Ex9NllL6Tg17-uY-3b9vU2laSfMViC3XnmgJuE7QJDq2BA-IcW4CXiHWJvppRcc0Ms4_OT6DCZ2LvcXS47t/s200/Headstone5.jpg" width="200" /></a>The viaduct design has been credited to <a href="https://en.wikipedia.org/wiki/William_Henry_Barlow">William Henry Barlow</a>, perhaps best known for the design of another Midland Railway project, the St Pancras train shed. Headstone Viaduct is far from his most notable bridge: along with John Hawkshaw, he completed Brunel's <a href="https://happypontist.blogspot.com/2011/01/did-brunel-design-clifton-suspension.html">Clifton Suspension Bridge</a>, and he also designed the replacement for Thomas Bouch's ill-fated <a href="https://happypontist.blogspot.com/2010/06/thomas-bouch-builder-of-tay-bridge.html">Tay Bridge</a>. However, Midland Railway engineer Frederic Campion may have held more direct responsibility.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh9T12qyUR8RYZ3EeQP3F7C4djaBbvga_fE0xTj0Qj7FdNvTW04IHIkr2RqHVToVBUUBvwiE743mbEwDTg6P634HsQCeCDowgaurjocvZ4YeiNCDMoA9SQwVFXCFH7jvjCvbNWumjkHejKj/s1600/Headstone7.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="1600" data-original-width="1201" height="200" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh9T12qyUR8RYZ3EeQP3F7C4djaBbvga_fE0xTj0Qj7FdNvTW04IHIkr2RqHVToVBUUBvwiE743mbEwDTg6P634HsQCeCDowgaurjocvZ4YeiNCDMoA9SQwVFXCFH7jvjCvbNWumjkHejKj/s200/Headstone7.jpg" width="150" /></a>The construction of the arch barrels is a little peculiar. The facing voussoirs on each arch comprise seven rings of brickwork (an inner two bonded together, and then five outer rings), down to springing level. The piers and spandrel walls are in rubble stonework, and stone is also used for the lower part of the inner face of the arch barrel. The upper parts of the arch barrel are in brick. It seems an odd arrangement.<br />
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Brickwork is also extensively employed above two arches on the south elevation, possibly associated with remedial work completed in 1907-8. I doubt that many visitors notice!<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgCG8rhkzsEYdsbRhXpWJabFW-667Q4S7xxeEInYkwPTfwEhoRal4JVotww2vsqzz1HzNUPUlzA1LDl0YCJriGYuOApTKfrW4iAv8LSFy3ifL9SGCzEQi-m6RqdYrKovEAscPq9iddMdbpE/s1600/Headstone4.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="881" data-original-width="1600" height="110" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgCG8rhkzsEYdsbRhXpWJabFW-667Q4S7xxeEInYkwPTfwEhoRal4JVotww2vsqzz1HzNUPUlzA1LDl0YCJriGYuOApTKfrW4iAv8LSFy3ifL9SGCzEQi-m6RqdYrKovEAscPq9iddMdbpE/s200/Headstone4.jpg" width="200" /></a>The overall impression is robust but not excessively so - the scale and nature of the bridge is entirely appropriate to its setting. It's interesting to wonder what would be built if a similarly beautiful valley were to be crossed by a new railway today.<br />
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The Victorian polymath and art critic <a href="https://en.wikipedia.org/wiki/John_Ruskin">John Ruskin</a> (something of a 19th century <a href="https://en.wikipedia.org/wiki/Brian_Sewell">Brian Sewell</a>) certainly didn't appreciate either the railway or the viaduct, writing:<br />
<blockquote class="tr_bq">
<i>"There was a rocky valley between Buxton and Bakewell, once upon a time, divine as the Vale of Tempe ... You Enterprised a Railroad through the valley - you blasted its rocks away, heaped thousands of tons of shale into its lovely stream. The valley is gone, and the Gods with it; and now, every fool in Buxton can be in Bakewell in half an hour, and every fool in Bakewell at Buxton; which you think a lucrative process of exchange – you Fools everywhere."</i></blockquote>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiXMrTSqaNhBO9YM2IlgqxAaPiE9nq83uVHro8Jkx7DdqG0uy-znFfMqq1f76m_DVR2yERja1foYzVg0Zu8OLa9WZx6xOUVacWzbjuvEG6GUralrTQdBaUXVt_eEptIMPxn5S2I2dmgzo9r/s1600/Headstone9.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="826" data-original-width="1469" height="222" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiXMrTSqaNhBO9YM2IlgqxAaPiE9nq83uVHro8Jkx7DdqG0uy-znFfMqq1f76m_DVR2yERja1foYzVg0Zu8OLa9WZx6xOUVacWzbjuvEG6GUralrTQdBaUXVt_eEptIMPxn5S2I2dmgzo9r/s400/Headstone9.jpg" width="400" /></a></div>
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As is often the case, age provides architecture not only with grace, but it also elevates the perception of the location as a whole. Without the viaduct, this could just be any other pretty green Pennine dale. The viaduct is the centrepiece, the thing that visitors peering down into the valley from above all point their cameras towards.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhpqLTRSk_vN-DRDtJo2YQ6spdqMZjrQT3Xh8uF3wCuufCB9XhVohxznRw1ka286RJtXxiaOTS6GIHD3xFXGBiwmFaFsE8w-OEimurVJeO-TV_br25zHFNvBZBdMD79x5X_bYa7g2YJ1YxV/s1600/Headstone2.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="900" data-original-width="1600" height="112" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhpqLTRSk_vN-DRDtJo2YQ6spdqMZjrQT3Xh8uF3wCuufCB9XhVohxznRw1ka286RJtXxiaOTS6GIHD3xFXGBiwmFaFsE8w-OEimurVJeO-TV_br25zHFNvBZBdMD79x5X_bYa7g2YJ1YxV/s200/Headstone2.jpg" width="200" /></a>It also provides a fine platform from which to view the surrounding greenery. Many visitors descend the path from the nearby Monsal Head car park to admire the viaduct and the tunnel entrance without going any further. An encounter with England's green and pleasant land need not require a lengthy trek.</div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgE1q2QuPL48oB_QHa4qhqWc8Scum4erwRwtPx_SwosR7I7jG3isy6RXS93u-JknG-Ow_8IaVFzb_bLajflduok5DKNhoogD9bvYqbQjBpz_KUF__VmniRMwXK9_SgqVS7miiVwv1pCfmIq/s1600/Headstone10.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="1472" data-original-width="1010" height="200" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgE1q2QuPL48oB_QHa4qhqWc8Scum4erwRwtPx_SwosR7I7jG3isy6RXS93u-JknG-Ow_8IaVFzb_bLajflduok5DKNhoogD9bvYqbQjBpz_KUF__VmniRMwXK9_SgqVS7miiVwv1pCfmIq/s200/Headstone10.jpg" width="136" /></a>It is certainly worth taking the time to go a little further and follow the path below the viaduct. From above it is impressive, but dwarfed by the surrounding landscape. From below, the opposite is true, it is a stone giant soaring overhead, framing shorter views and guiding the curious visitor eventually to the banks of the River Wye, ultimately responsible for carving this landscape over unimaginable years past.<br />
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It has obviously been a site for a more interactive visitor experience in the past. Signs on the viaduct draw attention to metal bars, suspended from the arches and stretched between the stone piers. These are intended to prevent people from leaping off the viaduct attached to a rope and swinging underneath. Certainly nobody was trying it when I visited.<br />
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Part of the railway line was <a href="https://www.peakrail.co.uk/our-railway/historyofline/">reopened as a "heritage" service</a> in 1992. There are broader ambitions to <a href="https://www.peaksanddalesrailway.com/reinstatement">reopen the whole route</a> as a "proper" railway, with Monsal Trail "reprovisioned", whatever that means. Personally, I think it would be a real shame if it denied people the chance to get up close and personal with the trail, its tunnels and viaducts.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjvKwhHjQ3e3ut6D8-Z3tJmuaR7NbtYip-fsdnb0c871p7G0VUpQjuD-iSUg87PEby18NCSqhwPZKnF_SdUqHa-RZMPsL3bW-uxJl2v8e8hLeER_jdkP6hqqKUjUnpx0RF6r-DJXPsrkCuC/s1600/Headstone8.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1102" data-original-width="1469" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjvKwhHjQ3e3ut6D8-Z3tJmuaR7NbtYip-fsdnb0c871p7G0VUpQjuD-iSUg87PEby18NCSqhwPZKnF_SdUqHa-RZMPsL3bW-uxJl2v8e8hLeER_jdkP6hqqKUjUnpx0RF6r-DJXPsrkCuC/s400/Headstone8.jpg" width="400" /></a></div>
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<b>Further information:</b></div>
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<ul style="text-align: left;">
<li><a href="https://www.google.co.uk/maps/@53.2407546,-1.727789,412m/data=!3m1!1e3">Google maps</a></li>
<li><a href="https://en.wikipedia.org/wiki/Monsal_Dale">Wikipedia</a></li>
<li><a href="https://britishlistedbuildings.co.uk/101109915-monsal-dale-viaduct-little-longstone">British Listed Buildings</a></li>
<li><a href="http://www.engineering-timelines.com/scripts/engineeringItem.asp?id=204">Engineering Timelines</a></li>
<li><a href="http://www.forgottenrelics.co.uk/bridges/gallery/monsal.html">Forgotten Relics</a></li>
<li><a href="https://www.nationaltransporttrust.org.uk/heritage-sites/heritage-detail/monsal-trail-viaducts">National Transport Trust</a></li>
<li><a href="https://www.ice.org.uk/getattachment/about-ice/near-you/uk/east-midlands/publications/monsal-trail/ICE_Monsal-Trail.pdf.aspx">Institution of Civil Engineers Monsal Trail leaflet</a> (PDF)</li>
<li><i><a href="http://happypontist.blogspot.com/2019/10/an-encyclopaedia-of-british-bridges-by.html">An Encyclopaedia of British Bridges</a></i> (McFetrich, 2019)</li>
<li><i>British Railway Bridges and Viaducts</i> (Smith, 1994)</li>
</ul>
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The Happy Pontisthttp://www.blogger.com/profile/15252272118786667592noreply@blogger.com1tag:blogger.com,1999:blog-6470543006314152962.post-41717210603532766442020-09-09T21:13:00.000+01:002020-09-09T21:13:00.271+01:00Derbyshire Bridges: 4. Railway Viaduct, Edale Road, Hope<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgc-kdxwsFvu9nKZy4rBbYj72oXRnHxRQ8zOs82jR1bZaNxMnsnRF7NSnPbWZnMZP_4NOkP6nXHQrKjwvgfqZ6OQQBZnTLPfRvqZAr389KpZAVOon7mpWG9Q5jDCO5YcAV_ZJE9ls8zhh44/s1600/Edale4.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1201" data-original-width="1600" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgc-kdxwsFvu9nKZy4rBbYj72oXRnHxRQ8zOs82jR1bZaNxMnsnRF7NSnPbWZnMZP_4NOkP6nXHQrKjwvgfqZ6OQQBZnTLPfRvqZAr389KpZAVOon7mpWG9Q5jDCO5YcAV_ZJE9ls8zhh44/s400/Edale4.jpg" width="400" /></a></div>
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This is another 1970s structure built to replace one of the original bridges on the Hope cement works railway line (for context on the railway, see my <a href="https://happypontist.blogspot.com/2020/08/derbyshire-bridges-2-railway-bridge.html">earlier post</a>).<br />
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The original 1929 bridge was a reinforced concrete trestle structure 347ft (106m) long, with eight spans of varying length. A 13ft (4m) wide deck slab spanned onto rail-bearers and crossbeams, which were supported from raised concrete girders on both edges of the deck. These then sat on reinforced concrete columns, braced with horizontal members to create H-frames.<br />
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The viaduct actually consisted of two structures, with a double-trestle in its middle and a copper expansion joint separating the two. The end trestles were buried within approach embankments, and will have provided stability against longitudinal loads from the railway. There is an image in <i>Concrete and Constructional Engineering</i> magazine which shows the finished viaduct:<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiRsAah7izdnnNL6dVhkHu548wcvWCupdQhY2OiyG4WQuU7qR6NW6icm5SO5Ujr9oEbC042cGZnttvsYWU6qjpQtVVNntEJQRdpzO3q-7hk5CO8GLe350q4g0_QZHoWcRmCuS8cNjXktDV0/s1600/Clipboard02.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="333" data-original-width="578" height="230" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiRsAah7izdnnNL6dVhkHu548wcvWCupdQhY2OiyG4WQuU7qR6NW6icm5SO5Ujr9oEbC042cGZnttvsYWU6qjpQtVVNntEJQRdpzO3q-7hk5CO8GLe350q4g0_QZHoWcRmCuS8cNjXktDV0/s400/Clipboard02.jpg" width="400" /></a></div>
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There is also <a href="http://www.family-bond.com/Geoff-V-Bond/Bridges/1974%20Hope%20Railway%20Bridge%20(new).JPG">a photograph on designer Geoff Bond's website</a> showing the 1929 structure hidden behind the new bridge, presumably pending demolition.</div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiYbyPHhuyn_kda80365nFKe2EoNR5dTLB4mIKrFiH2OZeKLv2m7uHB0aDmUG-Xqy7FEamwVqrEdk9d5jdF8Xp69SVxc-HUj9yhkeStU4S72eGD4cw0aShsOE0btRKd0bCf2PSuRb_aFasI/s1600/Edale1.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="1201" data-original-width="1600" height="150" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiYbyPHhuyn_kda80365nFKe2EoNR5dTLB4mIKrFiH2OZeKLv2m7uHB0aDmUG-Xqy7FEamwVqrEdk9d5jdF8Xp69SVxc-HUj9yhkeStU4S72eGD4cw0aShsOE0btRKd0bCf2PSuRb_aFasI/s200/Edale1.jpg" width="200" /></a>The present bridge is a 5-span post-tensioned concrete viaduct, carrying the railway over the Edale Road and the adjacent River Noe. I think it looks rather elegant in an <a href="http://www.family-bond.com/Geoff-V-Bond/Bridges/1973%20Hope%20Railway%20Bridge%20(new)%20artists%20impression.JPG">artist's impression from 1973</a>.</div>
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The main feature that makes it unusual is the way in which the lower flange of the box girder is extended outwards. Normally, such bridges extend only the upper flange (to form the road or railway deck), there is no obvious benefit to complicating things by extending the lower flange. Geoff Bond was a member of the design team at Oscar Faber and Partners, and <a href="http://www.family-bond.com/Geoff-V-Bond/Bridges/bridges.htm">his website</a> indicates that the rationale was <i>"to resist reverse bending moments and severe locomotive shear stresses"</i>.</div>
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I'm left slightly puzzled, and would love to have been able to find more information.</div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhMMQb1IlGLVRb7DeJ1VcqyrbhE6lGnp0nN9ynYkkp5uiFBHz7lVYO79geoatwEoUHfYl2A1NOt305NDuZQEoAe32zheLCj7q13C9FdkUm6wLUuLWQHIQbCPzAI110QsZtWo_7hykKr_xhC/s1600/Edale3.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1201" data-original-width="1600" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhMMQb1IlGLVRb7DeJ1VcqyrbhE6lGnp0nN9ynYkkp5uiFBHz7lVYO79geoatwEoUHfYl2A1NOt305NDuZQEoAe32zheLCj7q13C9FdkUm6wLUuLWQHIQbCPzAI110QsZtWo_7hykKr_xhC/s400/Edale3.jpg" width="400" /></a></div>
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<b>Further information:</b><br />
<ul>
<li><a href="https://www.google.co.uk/maps/@53.3544222,-1.745877,199m/data=!3m1!1e3">Google maps</a></li>
<li><i>Reinforced Concrete Bridges in Derbyshire</i> (Concrete and Constructional Engineering, 1929)</li>
</ul>
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The Happy Pontisthttp://www.blogger.com/profile/15252272118786667592noreply@blogger.com0