Enlarging of the spans of 14 continuous post-stressed overpasses in order to extend the A-7 Barcelona-La Junquera Highway to six lanes

Abstract

The article describes a simple construction process which provides the possibility of displacement of bridge piers when enlarging of spans is required to meet the demands of traffic under the bridge. The method is based on setting up a stretcher-like system consisting of two steel girders parallel to the structure. The girders gather the permanent forces of the old piers and transfer them to the new ones. In order to achieve the load transference from the old bridge to the new girders, a transverse prestressed web is used in both systems. In the new pier structure, the old deck and the two incorporated girders jointly resist the actions of the service overloads. Beside the pattern solution, the article describes some interesting variations for special cases such as curved, biaxially bent, double bridges, etc.