The effect of soil-structure interaction and liquefaction on the seismic vulnerability of typical port steel light-frame warehouses

Abstract

Ports play a crucial role in the world economy, as they represent critical nodes in regional and national transportation networks. They are usually located in areas prone to geohazards, such as earthquakes and soil liquefaction. Although warehouses constitute a port system's key components, the published literature in the evaluation of their seismic vulnerability considering the effect of soil liquefaction and soil-structure interaction (SSI) is generally inadequate. To bridge this gap, this study's objective is to implement a numerical investigation of the influence of both liquefaction and SSI on the seismic vulnerability of typical port steel light-frame warehouses. The following numerical modelling approaches are applied: i) a 2D fixed-base structure subjected to outcrop bedrock seismic motion neglecting SSI and liquefaction; ii)) a 2D flexible-base model, considering both SSI and liquefaction; iii) a 3D fixed-base model which is subjected to outcrop bedrock seismic motion and thus neglecting both SSI and liquefaction; iv) a 3D fixed-base model subjected to a free-field motion that considers liquefaction. We conduct nonlinear incremental dynamic analysis for the above numerical approaches to derive seismic fragility and vulnerability curves considering (or not) SSI and/or liquefaction. The earthquake demand is determined based on the selection of actual earthquake records covering a wide range of seismic input motions in terms of amplitude, frequency content, and significant duration. The comparative results show the considerable role of liquefaction and SSI in altering the seismic fragility and port warehouses' vulnerability.