The government had the intention, to let erect stone piers, as those withstand floods, ice pressure and impacts by rafts and boats better. But the river bed is always moving driven by the water flow, and so it let collapse the stone piers in years of flood. The art of the old Romans to put stone piers on a grid of beams, founded on timber piles, appeared to be unknown to the bridge-builders of Wangen, when they constructed a completely new bridge with only half of the number of piers: 3 timber piers on piles and 2 piers in stone. They used for the first time kingpost trusses to carry the heavy load of the tiled roof of almost 1,200 lb/foot length weight over spans from 50 up to 56 feet, giving a total maximum dead load of 66,000 lb. or 30 tons for one span equally distributed load. This is quite more than a wagon with horses at that time, which could run with about 5 tons on the 4 big main-beams between.

Fig.3 Stone Pier constructed in the year 1552

The same construction system was applied for three bridges in the neighborhood: In the year 1535 Neubruecke just north of Berne, 1568 Aarberg and 1555 Guemmenen. All of them are still in use, the former two for motor traffic up to 10 tons, the last one for pedestrians only. The settlements of accounts of the Bernese Government tell us in a detailed manner all the works that had been done to maintain the bridge usable during the centuries.

In 1934 the legal truck load was 16 tons and the bridge again was in bad shape. A project was made with steal beams but still protected by a roof to keep the appearence of a timber bridge. A bridge in iron-concrete was too expensive. An enterprise specialised in timber work proposed a solution with reinforcement of the 6 beams in each span, every beam 19x21 incches wide.

1552 is the date on the masonry stone pier Fig.3. In its whole size it was visible till 1967 but only in winter, when the river was low. Then the dam for an electric power plant rised the water up to the stone ring on which the struts for the reinforcements of 1934 are fixed. The water level of today is marked by a blue line.

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