Abstract

In the case of composite girders, the mechanical connectors are the elements being responsible for an effective cooperation of both parts of the composite section. At present welded stud shear connectors, which do not provide full interaction of a beam and a slab, are commonly used in steel-concrete bridges. In the paper the results of in situ load tests of a motorway steel-concrete composite bridge over the Warta river are presented. The bridge consists of two parallel continuous five-span structures. In the cross-section the structure has five steel girders connected with reinforced concrete deck slab, with use of welded shear studs. Effects of static and movable load tests are taken into account in the paper. The aim of the tests is identification of connection flexibility of the structure. The proposed connection coefficient  based on the values of strains measured in bridge beams is used. The values of strains in several cross-sections of the girders and span deflections for different load cases measured during the load testing of the bridge are shown. The values of strains are used to give an indication of the behavior of the bridge, and to determine values of the coefficients characterizing the degree of composite action of the girders.