Effects of Pounding and Fluid-Structure Interaction on Seismic Response of Long-Span Deep-Water Bridge with High Hollow Piers

This article aims to study the effects of pounding and fluid-structure interaction on a typical long-span deep-water bridge with high hollow piers. With potential-based fluid elements modeling fluid-structure interaction between hollow piers and water, and gap elements simulating pounding at gap locations, three-dimensional(3D) finite element models were built for the typical deep-water bridge. The longitudinal seismic responses of the bridge under the combination effects of pounding and fluid-structure interaction were studied from two cases where the hollow piers contact with outer water only and both outer water and inner water, respectively. For comparison, the individual effects of pounding or fluid-structure interaction were also analyzed. The results indicate that the fluid-structure interaction could be one of the critical factors which can result in pounding between adjacent segments of deep-water bridges, because the fluid-structure interaction can amplify the seismic relative displacement between adjacent spans of deep-water bridge. The combination effects of pounding and fluid-structure interaction are negligible on seismic responses of deep-water bridge piers compared with the individual effect of fluid-structure interaction; however, they can lead to further increase of deck displacement of approach span, no matter compared with the individual effect of fluid-structure interaction or pounding, which increases the possibility of approach span unseating. Whether pounding happens or not, the existence of the inner water in the hollow piers causes aggravated effect on seismic responses of deep-water bridge.