Investigation of the effect of spatially varying ground motion components on the dynamic behaviour of cable-stayed bridges depending on soil conditions

Abstract

In this study, it is aimed to investigate the dynamic characteristics of cable-stayed bridges with respect to the spatially varying ground motion components of wave-passage and incoherence effects. While examining the relative effects of the spatially varying ground motion components on the dynamic behavior of cable-stayed bridges, homogeneous firm, medium and soft soil conditions are included. For this purpose, the simulation method proposed by Hao is used to generate ground motion time histories depending on the spatially varying components of incoherence and wave-passage effects. To emphasize the relative importance of the spatial variability effects of the earthquake ground motion, bridge responses are determined for the fixed base bridge model and for the bridge model which includes the soil-structure interaction effect. The substructure method which partitions the total soil-structure system into two substructures: the structural system and the soil system, is used to treat the soil-structure interaction problem. The parametric study of the relative importance of the spatially varying ground motion components shows that while the incoherence effect usually dominates the structural responses for firm soil condition case, the wave-passage effect is much more effective than the incoherence effect for the weakening soil conditions.