THE BRIDGE OVER THE SEINE ALONG THE MELUN THROUGH-ROAD, THE FUTURE OF PRECAST GIRDER BRIDGES

The Melun through-road, 2650m long, crosses the town from north to south. It crosses the seine by means of a viaduct, original in its design and its appearance. The structure has an overall length of 268m and an overall width of 24m; it comprises 7 42m or 34m spans. The bearings are founded (1) on land and rest on cast-in-situ piles, and (2) in the river on large concrete masses which were built behind the protection of a cofferdam. The piers consist of two shafts crowned by two precast rafters, which support the bearings of the deck girders and are positioned in a radiating way so that, in spite of the plane curvature of the structure, the girders of the same span are of the same length. The deck, which is of the statically determinate multi-girder type, comprises light precast prestressed girders, launched by means of a small bailey bridge, and a cast-in-situ floor over a preslab. A brief description is finally presented of the present state of the art of the construction of precast girder bridges. /TRRL/