Nonlinear analysis of composite steel–concrete cable-stayed bridges

This paper presents the nonlinear analysis of composite steel–concrete cable-stayed bridges. The composite deck and the concrete towers are modeled by three node/7dof steel and concrete frame elements, shear connection of the deck is modeled using continuous spring elements. Geometrical and material nonlinear behaviours of both steel and concrete materials are considered. Cable’s sag and time dependent effects due to load history, creep, shrinkage and aging of concrete are also included in the analysis.The main sources of nonlinearity are evaluated for a 420 m main span composite cable-stayed bridge, under service conditions. The failure load and the failure mechanism are also analysed, both at the end of construction and at long term. The influence of the following factors is studied: (1) deck load pattern, (2) time dependent effects, (3) cables’ yielding and “cable-out” effect, (4) existence of intermediate piers at the lateral spans, (5) effective slab width, and (6) flexibility of the shear connection.