Dynamic Analyses of Two Buildings Founded on Liquefiable Soils during the Canterbury Earthquake Sequence

Abstract

A series of major earthquakes near Christchurch, New Zealand, produced different levels of liquefaction-induced ground failure and damage to multistory buildings in the city’s central business district. Observations of seismic performance during the 2010–2011 Canterbury earthquake sequence provide a unique data set for evaluating design procedures. Nonlinear dynamic soil-structure interaction analyses of two shallow-founded multistory buildings that were damaged by moderate liquefaction-induced settlements provide useful insights. Nonlinear effective-stress fully coupled soil-structure interaction analyses were performed using the finite-difference method with a widely used constitutive model for soil liquefaction calibrated with field and laboratory test data. The results show good agreement between observed and calculated responses of the ground and the structure during the earthquake events. Shear-induced ground deformation was a key mechanism of liquefaction-induced settlement of the structures. This mechanism was captured well in the two-dimensional analyses. Liquefaction-induced volumetric-induced ground deformation was also important and captured in the analyses. However, the influence of ejecta-induced building settlement was not captured.