Service and ultimate behaviour of composite steel-concrete beams subjected to combined bending and shear

This paper describes the behaviour of composite steel-concrete beams subjected to combined bending and shear at both service and ultimate conditions. In particular, it is shown that for realistic composite bridge arrangements it is important to account for the shear deformability of the steel beam for an accurate prediction of the instantaneous and long-term deflections, which otherwise might be underestimated. At the ultimate limit state conditions, it is highlighted that for an adequate evaluation of the composite response subjected to significant actions of combined moment and shear force, it is necessary to consider the shear behaviour of the steel and slab components. This is accomplished comparing the results of three composite beam models accounting for the deformability of the shear connection at both service and ultimate conditions, while varying the beam models adopted to represent the response of the slab and the steel beam. The proposed formulations could be used to complement the analysis tools available to bridge designers