New bridge to replace an old viaduct in Ottendorf, Germany
Railroad overpass on the Mittweida–Chemnitz line
In 1852, a 70-meter-long viaduct was built that spanned the Ottendorfer Bach valley in the western part of Ottendorf. Being susceptible to weather damage, the sandstone was given a protective concrete coating in 1955, and after a period of almost 60 years the protective layer was no longer effective. Several alternatives had been examined as to how the viaduct could be restored and retain its original form. However, the results showed that this was not possible, and so the viaduct was replaced with a new bridge.
The abutments of the arched bridge were retained when the old viaduct was dismantled. A frame was constructed behind the abutments to restore the structure’s load capacity. This took the form of a U-shaped deep foundation consisting of bored piles. This frame forms the supporting surface for the arched bridge’s new support structure. The arched bridge was pre-assembled on a temporary support structure, on which it was then pushed into place. The tied arch chosen was designed as a frame-reinforced arched supporting structure. The central section is a tied arch with the rail track suspended on flat steel hangers. The arch pierces the stiffening girder and together – along with the downward extended arch ribs – they form a frame that gives additional support. The old abutments were only partially demolished and received supporting elements made of reinforced concrete for the upper termination; the exposed side was completely covered with concrete cladding. Having suffered damage in the past, the parallel wing walls of the arched bridge were buried in the embankment and replaced by angled wing walls.
