Benchmarking and Safety Assessment for Modified Lateral Spreading Design Procedure using Three-Dimensional Nonlinear Finite Element Analysis

Abstract

Liquefaction-induced lateral spreading is a critical design consideration for many bridges in high-seismicity regions of the Pacific Northwest, with broad impacts on safety for the general public. The bridge design procedures currently used in the region tend to account for the effects of lateral spreading in a simplified manner that captures the general impact of this phenomenon on the bridge components but omits many key details such as three-dimensional soil deformation. Modifications to this current design approach will not only lead to more cost-effective design solutions, but will increase public safety by reducing the potential for bridge collapse and minimizing lost service time. An improved design framework has been proposed to supplant the current method; however, relatively little focus has been given to the validation and verification of this new procedure. Before widespread acceptance of this modified approach, it is critical to verify that its application will result in improved design solutions that reduce the costs associated with the conventional approach while remaining safe for use. This work aims to verify the modified simplified design procedure against 3D finite element models and to increase our understanding of the site geometry conditions that necessitate a more comprehensive consideration of 3D effects in foundation design by using a large parameter study.