"China's Unique Woven Timber Arch Bridges" by Zhou et al

I don't normally make a point of mentioning technical papers on this blog, but maybe it's something I should do from time to time. I have previously wondered about putting together a semi-regular roundup of papers that might be relevant or interesting to my readers. However, I don't want to make more work for myself, so this may only very rarely happen!

I did think that this paper was worth drawing to wider attention: "China's unique woven timber arch bridges" (Zhou, Leng, Zhou, Chun, Hassanein and Zhong, Proc. ICE - Civil Engineering, August 2018).

This gives an overview of timber bridges in China of a type that dates back over 1000 years. I first properly encountered them in Ronald Knapp and Chester Ong's excellent book Chinese Bridges, which presents several bridges from the Zheijang and Fujian regions. The design and construction of these bridges is considered important enough for them to be included on UNESCO's Intangible Cultural Heritage List since 2009. A historic example, the Rainbow Bridge, is illustrated on the Song Dynasty painting Along the River During the Qingming Festival (~1085-1145), pictured above.

Nearly 100 of these woven timber arch bridges survive. Several have fallen victim to disaster through fire or flooding, including at least one of the bridges featured in Knapp's book. However, the construction skills have undergone a revival, such that some of these bridges have since been rebuilt. Indeed, the paper lists some 19 woven arch bridges which have been rebuilt or newly built since 1999.

The essence of these bridges is the structural form of a woven polygonal arch, which is described in detail in the paper, including several construction photographs. It consists of two sets of arch members which alternate across the width of the bridge, so that there are two superimposed polygons. These are locked together by transverse timbers, creating a triangulated system which in one way behaves not like an arch, but like a beam. However, it must also behave as an arch, as the main timbers are carefully butted together to be able to transmit axial load.

The paper in the ICE Proceedings is a short (6 pages) but very clear and useful introduction to these amazing bridges, and definitely worth a read if you have access to it. In case anyone would like to learn more about the woven arch bridges, I've collected a set of links to more detailed technical papers at the bottom of this page.

It wasn't until several centuries later that a similar bridge design was developed in Europe by Leonardo da Vinci. His design is discussed in a 2004 paper by Ceraldi and Ermolli, which compares da Vinci's design to the earlier Chinese bridges. Da Vinci's solution does not use the butted timbers, and is an open frame rather than having many alternating arches all immediately adjacent to each other.

Further information:

• Chinese Rainbow Bridges (Shen and Liu, World Conference on Timber Engineering, 2004)
• Timber Arch Bridges: a design by Leonardo (Ceraldi and Ermolli, 4th International Conference on Arch Bridges, 2004)
• Timber Arch Bridges in China (Yang, Chen and Gao, 5th International Conference on Arch Bridges, 2007)
• Tectonic Studies on Wooden Arched Bridge. As the Case of Span in Chinese Wooden Construction Tradition (Zhao, Feng and Bi, Third International Congress on Construction History, 2009)
• Traditional construction technology of China timber arch bridges (Yang, Nakamura, Chen and Nishikawa, Journal of JSCE, 2012)
• Structure, Construction and Craftsmanship of the Timber Woven-Arch Bridge in China (Liu, Second National Covered Bridge Conference, 2013)
• Chinese Ancient Arch Covered Bridges (Liu, Second National Covered Bridge Conference, 2013)
• Historical Culture and Traditional Craftsmanship of Taishun County (Ji, Second National Covered Bridge Conference, 2013)
• Discovering China's 'Forgotten' Bridges (Knapp, Second National Covered Bridge Conference, 2013)
• The Origin of Timber Arch Bridges in China (Yang, Nakamura, Chen and Nishikawa, Journal of JSCE, 2014)

China bridge tour 2013

Eric Sakowksi, the man behind the highestbridges.com website, is planning another 3-week bridges tour in China, from 3rd to 24th August 2013. Participants will visit 12 of the 13 highest road bridges in the world; the sites of what will be the world's new highest road and rail bridges, currently under construction; the world's two largest rail viaducts; an exceptionally long span footbridge; and many other marvels.

Anyone interested can find out more online. For a taster of what is in store, Eric has recently added some photo albums from his 2012 China bridge tour to his site, and the 2011 China photo album is still there as well. Both are highly recommended.

"Chinese Bridges" by Knapp & Ong

I've recently been reading "Chinese Bridges: Living Architecture from China's Past" by Ronald Knapp and Chester Ong (272pp, Tuttle Publishing, 2008) [amazon.co.uk]. Well, I say, reading, but for the most part I have been marvelling at the pictures.

I'm not sure which Chinese bridges are best known worldwide, but I'd guess the most famous might include the Zhaozhou Bridge (pictured, below left, courtesy jrs65), Beijing's Jade Belt Bridge (pictured, below right, from the book), or the 2km Anping Bridge. All three are remarkable historic stone bridges, with the Zhaozhou Bridge particularly impressive for prefiguring similar Western achievements by many centuries.

More assiduous pontists will know that China is also in the midst of a truly massive bridge-building programme today: already, 8 of the 10 highest bridges in the world have been built in China, as well as 4 of the 10 longest spans.

However, the scale of the country is such that these represent only the tip of a very, very large iceberg. Luckily for us ignorant gwailo, Knapp and Ong's book helps expose a little more of China's vast and rich bridge heritage.

It's a lovely coffee-table tome, amply illustrated with Ong's excellent photographs of bridges both famous and unknown. I don't think there's a page without a good photo on it. It also draws extensively on historic Chinese prints and paintings, and is clearly a labour of love.

The book is in three parts. The first is a general history of "ancient" Chinese bridge building, a journey through different bridge forms ranging across "step-on block bridges" (stepping stones), megalithic stone beam bridges, traditional chain bridges and more. One thing that is peculiar is that despite a wealth of detail, little is said on the bridge designers and builders themselves - there's no figure like Perronet or Telford here. Partly this is because the book's focus is before the "engineering" age of bridge building, but it may also relate to a lack of available information, or to the inability of individual bridge builders to build a reputation across such a huge country. This section introduces a number of bridges covered in more detail later in the book.

The second part addresses Chinese bridges as "living architecture", and discusses the relationship of traditional folk culture, feng shui, and religion to Chinese bridge building and use. Many historic Chinese bridges were or remain the sites of Buddhist, Taoist, or other temples, and many more are decorated with traditional emblems intended to bring good fortune or ward off disaster. Attention to auspicious dates and rituals played an important part in the building of many bridges, to the extent that bridges sometimes lay half-complete for considerable periods awaiting the "correct" date to proceed to the next stage.

The main part of the book is a gazetteer of over thirty particularly remarkable structures, "China's fine heritage bridges". Knapp's text for each bridge often ranges far and wide beyond the structure itself. When discussing the garden bridges of Beijing, for example, the reader will learn as much about the history of the Palace gardens as about the structures that ornament them. For others, like the canal bridges of Zhejiang, the text discusses in detail local trades and crafts.

Not all the bridges are spectacular - several are essentially minor structures of little fame or historical significance. However, they amply demonstrate the charm of vernacular bridge building, and that's reason enough to feature them.

Easily the highlight of the bridges included is a thirty-page section on Chinese covered wooden bridges, particularly of the "woven timber arch-beam" type. These are perhaps less well-known (Troyano's supposedly comprehensive Bridge Engineering: A Global Perspective ignores them, for example), but for me they are the main attraction of the entire book. While there are many examples of covered bridges throughout the book, this section concentrates on a particular sub-species, exemplified by rough-hewn behemoths like the Yangmeizhou Bridge (pictured, left, from the book).

While some in this group consist of straight beam bridges, with some similarities to the well-known covered bridges of Switzerland and the USA, most are massive timber "arches", supported by logs interlocked together in a polygonal form. The structure is generally hidden behind timber slat cladding, giving them a coarse, inelegant appearance. I find them quite beautiful.

Knapp's own website has a series of PDFs illustrating a variety of Chinese covered bridges, but it's no substitute for holding this exceptional book in your hands.

China Bridges Trip 2012

Here's one for the wealthy (and slightly nutty) of you.

Erik Sakowski, creator of the truly mighty highestbridges.com website, is organising a 3-week tour of bridges along China's Yangtze river. The itinerary will take in 5 of the world's 10 longest suspension bridges, 5 of the world's 10 longest cable-stayed bridges, 5 of the world's 10 longest arch bridges, and many more superlative-loaded treats for the ambitious pontist.

It's a genuine snip at an all-inclusive US$3,950 (excluding air fares to and from Shanghai), and you just need to read the preview to see how amazing it will be. If that's not convincing enough, spend a good hour looking over Eric's mouth-watering photos from his 2011 China bridge trip. Hopefully he won't mind that I've borrowed one of his 2011 photos below to give you a flavour.

Jinsha footbridge design competition

I will join a number of other websites who seem to parrot each others' news by reporting the shortlist for a new pedestrian bridge design competition in China. This one is for a 400m long structure at Jinsha Lake in Hangzhou, and the invited designers are:

• Denton Corker Marshall
• Grimshaw
• Marc Mimram with Tianjin Urban Planning & Design Institute
• Petroff Partnership Architects
• Wilkinson Eyre
• Zaha Hadid

That's all I know, so if anyone can point me towards more information, that would be appreciated.

2011 China Bridge trip

Now, this sounds like just the most fantastic holiday ever, for a pontist so deeply committed as to be practically certifiable.

Eric Sakowski, of the great website highestbridges.com, is organising a three-week trip to China to visit dozens of bridges including the eight highest spans in the world, and many more truly spectacular structures, often in remote parts of the country that Westerners almost never visit.

The tour runs from 5-26 August 2011, and costs less than US$4,000.

Eric's trip preview really has to be read to be believed, and his advice for anyone else looking to make a similar trip is also well worth reading.

Sadly, the Happy Pontist won't be going.