tag:blogger.com,1999:blog-6470543006314152962.post2753179634481154133..comments2024-03-11T16:49:27.614+00:00Comments on The Happy Pontist: Scottish Bridges: 4. Harthill FootbridgeThe Happy Pontisthttp://www.blogger.com/profile/15252272118786667592noreply@blogger.comBlogger3125tag:blogger.com,1999:blog-6470543006314152962.post-58261052910277788542009-12-11T09:44:34.421+00:002009-12-11T09:44:34.421+00:00Given that I visited the bridge in April 2009, and...Given that I visited the bridge in April 2009, and Glasgow's Evening Times (http://www.eveningtimes.co.uk/bridging-the-gap-on-m8-1.963403) wrote about its erection in October 2008, I can't understand this comment at all. The £5m figure comes from the same Evening Times article, it certainly sounds about right comparing the bridge and its ramps to other motorway footbridges elsewhere.The Happy Pontisthttps://www.blogger.com/profile/15252272118786667592noreply@blogger.comtag:blogger.com,1999:blog-6470543006314152962.post-52568150027124636082009-12-11T00:16:50.891+00:002009-12-11T00:16:50.891+00:00The bridge wasn't put up untill later months o...The bridge wasn't put up untill later months of 2009 so believe what you will of main post. What I'm interested in is the cost? Is £5 million correct?Fitzy_xhttps://www.blogger.com/profile/09436851708236930390noreply@blogger.comtag:blogger.com,1999:blog-6470543006314152962.post-84131153936578116822009-05-05T15:47:00.000+01:002009-05-05T15:47:00.000+01:00Since posting the above, I've had a chance to ...Since posting the above, I've had a chance to read "Helical design for footbridge" (The Structural Engineer, 87, March 2009, S. Fryer & A. Allegri), which discusses the technical aspects of the design in more detail.<br /><br />Of interest in the context of my posting are the bridge's reliance on its eight longitudinal tubes (four below the deck, four above), which act as the top and bottom chords of the truss and resist most of the bending. These are visible on some of the photos, but are visually subservient to the encasing helical "shell", which I think is a little awkward - as in a building structure, the element which might be considered structurally secondary is given visual emphasis.<br /><br />Variation in strength along the span is attained by varying the internal wall thickness of the tubes, from 12.5mm up to 40mm (the helical tubes are 168mm diameter, so 40mm wall thickness is really quite chunky). Again, it's unfortunate that the visual form doesn't reflect this, but that flows inevitably from the initial design decision to adopt a helical tube system.The Happy Pontisthttps://www.blogger.com/profile/15252272118786667592noreply@blogger.com