Structural Analysis of Composite Cable-Stayed Bridges

This paper presents the nonlinear structural analysis of composite steel-concrete cable-stayed bridges. The composite deck and the concrete towers are modelled using the three node/7dof steel and concrete frame elements; stays and shear connection of the deck are modelled using cable and continuous spring elements. Geometrical and material nonlinear behaviours of both steel and concrete materials are considered. Time-dependent effects due to load history, creep, shrinkage and aging of concrete are also included in the analysis. An evaluation of the main sources of nonlinearity is made for the case of a 420 m main span composite cable-stayed bridge, at service conditions. The failure load and failure mechanism of this composite cable-stayed bridge are also investigated, both at the end of construction and at long term, the influencing factors analysed being, namely: (a) the deck load pattern, (b) the time-dependent effects, (c) the intermediate piers in the lateral spans, (d) the effective slab width and (e) the flexible connection.