Parameter study to examine role of 3D geometric effects on bridge foundation loads resulting from demands of liquefaction-induced lateral spreading

Abstract

Liquefaction-induced lateral spreading is a critical design consideration for many bridges in high-seismicity regions. Bridge foundation design procedures based on the pile pinning concept adequately account for the three-dimensionality of the problem, but do not offer much guidance on the expected significance of foundation pinning at a particular site. The purpose of this study is to quantify how changes in the 3D site geometry contribute to changes in the foundation bending demands during lateral spreading, and to identify the critical site geometric features that lead to reductions in foundation demands relative to a plane strain analysis. These objectives are accomplished using a parameter study carried out using 3D finite element models of the soil-foundation system that consider different combinations of approach embankment width, crust thickness, liquefiable layer thickness, and foundation-to-soil stiffness ratio.