The tourist office in canton Bern’s Emmental region is about to publish a unique travel guide to several of its most important historical monuments – its wooden bridges.This content was published on October 23, 2003 - 09:23
More than two-dozen timber bridges span the region’s main river, the Emme, and its tributaries. Some of them are outstanding feats of engineering.
Konrad Meyer-Usteri, a retired civil engineer and the author of the guide, took me on a tour of some of the region’s bridges. The starting point was the Hasle Bridge.
“At nearly 60 metres it’s the longest span of any historical wooden bridge in Europe,” Meyer-Usteri explained as we stood beneath the Hasle.
“That makes it very similar to the arch bridges of the well-known 18th century bridge builder, Hans Ulrich Grubenmann, of eastern Switzerland.”
Few of Grubenmann’s bridges have survived, which makes the one at Hasle all the more important, and gives it pride of place in the new guide to Emmental’s timber bridges.
Grubenmann’s bridges were considered by the great 18th century British architect, Sir John Soane, as masterpieces of engineering and he often singled them out in his lectures as examples of inventive construction.
The arch bridge was revolutionary because it allowed the entire structure to be raised above the water, sparing it from flooding.
That was a key concern in the Emmental in the first half of the 19th century. A great flood destroyed many of its bridges in 1837, which spurred local builders to copy Grubenmann’s technique.
The only bridge to have survived the flood unscathed was, not surprisingly, the region’s only arch bridge – the Horben – about 25 kilometres upstream from the Hasle.
Built in 1834, it still stands in its original location, serving traffic on the main road between the towns of Schupbach and Eggiwil.
“It’s a living witness to the history of the Emmental,” Meyer-Usteri says.
About a third of the 31 structures listed in the guide are arch bridges. There are also early specimens of truss, suspension and girder design. The oldest date back to the second half of the 18th century.
Over the past couple of decades, many of the bridges have been dismantled and moved a short distance up- or downstream, making way for wider modern structures that can handle two-lane traffic.
But what first impressed Meyer about the wooden constructions was their ability to bear the heavy loads of today’s traffic, even though they were only built to withstand the weight of pedestrians, horses and carts.
This came as a revelation to him early in his career when he discovered that - with some reinforcement - they were capable of supporting 28-ton trucks.
His findings and efforts were key to the preservation of some of the structures, which he says are an important part of the region’s heritage and ambassadors for Emmental’s timber industry.
“They prove that wood is suitable for load bearing structures, and of course we want to promote the use of wood,” he explains.
“It’s a natural resource and a sustainable building material,” Meyer adds. “We want to be able to harvest the wood from our forests but at present we don’t take full advantage of what we have.”
But the new guide also lists several timber bridges which are less than 20 years old.
Some are copies of the older covered bridges they have replaced, while others are modern constructions, not recognisable at first glance as timber bridges.
swissinfo, Dale Bechtel in the Emmental
The Timber Bridges guide is due to be released in early 2004.
The guide will be in German, but the Emmental tourist office will make an English version available to download from its website.
There are more than 200 historical timber bridges in Switzerland and about 70 new wooden structures, mostly for pedestrians.
Switzerland’s best-known builder of wooden bridges was Hans Ulrich Grubenmann, 1709-1783.
In compliance with the JTI standards