Bridge in Narrow Waterway: Seismic Response and Liquefaction-Induced Deformations

Abstract

Considerable bridge-ground interaction effects are involved when evaluating the consequences of liquefaction-induced deformations. Due to seismic excitation, liquefied soil layers may result in substantial accumulated permanent deformation due to the sloping ground near the abutments. Ultimately, global response of the bridge is dictated by soil-structure interaction considerations of the entire bridge-ground system. Of particular interest is the scenario of narrow waterways where interaction between downslope deformations at both ends of the bridge takes place. In order to highlight the involved salient mechanisms, this study investigates the longitudinal response of an overall bridge-ground system. For that purpose, a full three-dimensional (3D) finite-element (FE) model is developed, motivated by details of an existing narrow waterway bridge-ground configuration. As such, a realistic multilayer soil profile is considered with interbedded liquefiable/nonliquefiable strata. Specific attention is given to global response of the bridge structure as an integral entity due to ground deformation in the vicinity of the abutments. The overall results indicated that downslope deformations at both ends of the bridge may result in significant interference within the narrow waterway central section. As such, assessment of deformations at each slope separately might lead to unrealistic outcomes. Generally, the analysis technique as well as the derived insights are of significance for the seismic response of bridge systems with downslope ground deformations.