Seismic fragility analysis of concrete pile-supported wharves based on single-degree-of-freedom model

Abstract

This study proposes a new procedure to predict the seismic fragility curves of concrete pile-supported wharf based on an equivalent single-degree-of-freedom (SDOF) model. The SDOF model is utilized to substitute the practical wharf structure during probabilistic seismic demand analysis for reducing the computational cost and complexity. The trilinear backbone cure and Pivot hysteresis model, whose parameters are determined by the pushover analysis of actual wharf, are incorporated in the SDOF model to represent hysteresis characteristics and strength degradation of wharf. To validate the reasonability of the proposed procedure, two case studies are conducted by comparing the difference of fragility curves developed from actual wharf and its equivalent SDOF model based on the cloud method. The results show that the curves are located very closely on the graph, and the curve of SDOF model is generally above that of actual wharf, which indicates that the SDOF model may provide a conservative assessment for fragility analysis of wharf.

Magnification factor for pile internal forces of pile‐supported wharves under bi‐directional ground motions

“…It is well known that the ports in the U.S. have adopted the displacement‐based seismic design method, but the force‐based method is still permitted for preliminary design and non‐significant structures [19, 20]. Different from the displacement‐based method, the internal force analyses of component for wharf structures are the main content of force‐based design, and the combination rules are recommended by the current design practice to calculate internal forces, which need three‐dimensional models to address bi‐directional ground motion and critical incident angle.…”