Effects of spatial inhomogeneity of wave excitations on structural behaviors of multi-span floating bridges

Abstract

Floating bridges have wide application prospect in deep-water transportation infrastructures. However, limited research works have been conducted to study the structural behaviors of such type of structure under various wave conditions. In this paper, a novel time domain approach, which combines dynamic finite element method and state-space model, is proposed for the refined analysis of floating bridges. High-precision fitted state-space models are established to enhance the calculation efficiency of motion-induced radiation forces. The presented method is verified by applying it to simulate a physical scaled model test. Upon verification, the developed approach is further employed to investigate the effects of spatial inhomogeneity of waves on the dynamic behaviors of multi-span floating bridges, where two bridges with five and seven spans as well as four wave conditions of different wave height distributions, are considered for comparative analyses. It is shown that inhomogeneous waves could mitigate the horizontal responses of multi-span floating bridges, while the structural responses in vertical direction could be enhanced. The dynamic responses of multi-span floating bridges could be more sensitive to the wave inhomogeneity as the bridge length increases. Furthermore, the effects of short-crested and long-crested waves on the structural responses are also compared in this study.