A substructure shake table test method for pile-supported wharves: Numerical validation

Abstract

To investigate the seismic performance of pile-supported wharves (PSW), 1 g shake table testing with large-scale specimens is an effective dynamic testing method. However, scaled soil is challenging to replicate the pile-soil interactions (PSI) accurately. Large soil mass also occupies the shake table load capacity, limiting the testing of large-scale specimens. This work proposes an offline real-time substructure shake table test (offline RSST) method for PSW, eliminating the heavy-load soil box to facilitate large-scale PSW specimen loading with reduced costs. In offline RSST, the wharf is divided along the soil surface into "superstructure" and "foundation". The foundation is simplified into an amplifier connected in series with the superstructure to form a wharf substructure (WS). The lateral stiffness of the amplifier is tuned to make equal the fundamental periods of the WS and the wharf prototype. Furthermore, an offline FFT/IFFT procedure is employed to adjust the WS's input wave to replicate the dynamic response of the wharf prototype. To verify the offline RSST, the wharf prototype and WS's seismic responses are compared in the numerical domain, presenting frequency domain error of 3 %, 17 % and 6 % for PSW deck accelerations, structural displacements and pile head moments. These results indicate that the offline RSST has reasonable accuracy with a theoretical basis, providing a feasible platform for engineering-oriented dynamic testing for PSW.