Seismic Ground Deformation Analyses for the Design of a Large Outfitting Pier in North Vancouver, BC

This paper presents seismic numerical analysis of a proposed outfitting pier at Seaspan’s Vancouver Shipyards facility, located in North Vancouver, British Columbia. The study focuses on evaluating seismic liquefaction-induced deformation along the pier. Two-dimensional seismic ground deformation analyses were conducted using the finite difference computer program FLAC, incorporating advanced soil constitutive models PM4SAND and PM4SILT to simulate the response of sand and low-plasticity silt layers, respectively. The seismic response was analyzed using a dataset of 30 earthquake records, selected to capture a wide range of seismic scenarios. The analysis indicated that the nearshore slope area experiences the largest ground deformation, with magnitudes ranging from 4 to 6 m toward the downslope to the south. Beyond approximately 150 m from the north end of the pier, the deformation diminishes to insignificance. These findings align with the results obtained from the one-dimensional seismic response analysis, validating the consistency of the FLAC analysis approach. The results of the FLAC analysis were used as input in the structural analyses and design of the proposed pier’s pile foundations.