Impact of Ground Freezing on Seismic Performance of Bridge Pile Foundations Subject to Liquefaction-Induced Lateral Spread

Lessons were learned from two major earthquakes in Alaska: the freezing of ground crust had a great influence on bridge pile foundation behavior during lateral spread. Based on a typical bridge from the Alaska Department of Transportation and Public Facilities bridge inventory, supported on commonly used pile foundations that penetrate a liquefiable sand layer, finite element (FE) modeling was used to study seismic performance of bridge foundations subject to liquefactioninduced lateral spread in two scenarios: the frozen case, in which a frozen ground crust represented typical winter conditions, and the unfrozen case, in which an unfrozen ground crust represented summer conditions. Soil reactions and pile responses were analyzed with solid-fluid coupled FE modeling. Results for both cases illustrate the key characteristics of pile performance. In addition, the effectiveness of the p-y approach for predicting the pile response under such a complex loading combination was confirmed by a comparison of the results from LPILE with those from coupled FE modeling, and this approach is recommended for practice. Guidelines are proposed for design practitioners to assess the freezing ground impact on pile foundations with the p-y approach.