Evaluation of ASCE 61-14 Nonlinear Static Procedures for Estimating the Seismic Response of Wharves

This paper examines the nonlinear static procedures (NSPs) available in the design Standard ASCE 61-14 for estimating the seismic response of marginal wharf structures. Three-dimensional wharf model structures on simulated soil conditions ranging from soft to stiff under bi-directional ground motion excitation were considered in the analyses. Results from NSPs were compared against benchmark values of engineering design parameters (EDPs). The latter are defined as the geometric mean demands (forces and deformations) that are obtained from nonlinear dynamic analyses with a set of 30 two-component ground motion records. It was found that, the substitute structure method (SSM) in ASCE 61-14 generally overestimates the benchmark displacement demands at the center of mass of the wharf, especially for short period structures. For the most critical pile connection at the landside corner, the 100/30 directional combination and the dynamic magnification (DMF) approaches in the standard produced displacement and curvature demands that overestimated the benchmark values for short period but underestimated the benchmark values for long period marginal wharves. The two approaches, however, produced results that are consistent with one another. It is concluded that the NSPs of ASCE 61-14 may not be adequate for the seismic design of flexible marginal wharves supported on plumb piles.