Liquefaction-induced lateral spreading is a critical design case for many bridges located in high-seismicity regions of the Pacific Northwest. The design procedures currently used in the region tend to rely upon a simplified 2D plane strain analytical approach, and as a result may result in overly conservative and expensive design solutions. In some cases this over-conservatism has limited the feasibility of entire bridge projects. Given the shortcomings of the current design procedure, a modified design framework has been proposed to supplant the existing approach. This modified procedure takes an equivalent static approach (ESA) that makes consideration for 3D effects and foundation pinning through the combination of a foundation pushover analysis with a pseudo-static slope stability analysis to find a compatible foundation displacement as shown below
