The study on yield acceleration and permanent displacement of broken-back gravity quay walls – a case study

Abstract

In the recently developed performance-based design method, permanent displacement is a key parameter for evaluating seismic performance quay walls, which can be achieved by fully dynamic and simple pseudo-static limit equilibrium (PS-LE) based methods. PS-LE methods have some ambiguities concerning the calculation of yield acceleration (ay ); therefore, the present study shows an alternative approach to determining ay based on the recently proposed limit analysis technique: Discontinuity Layout Optimization (DLO). The seismic performance of quay walls located in the Pars Petrochemical Port is evaluated as a case study. Firstly, according to the wall’s geometry, a modified expression of ay for PS-LE methods is provided. The parametric studies illustrate that the DLO gives a higher acceleration (ay = 0.271 g) than the LE method (ay =0.196 g). Then, a simple dynamic Finite Element (FE) analysis is also conducted to assess the permanent displacement. Comparison of resulting displacements with pseudo-dynamic (PD) methods indicated that accurate acceleration could lead to good agreement between Whitman and Liao as a PD (dmax=21cm) and FE (dmax=23.46 cm) analysis. Eventually, it is demonstrated that besides retaining the features of simple analysis, the DLO technique is more adaptable to complex geometries and offers a more realistic failure mechanism than the PS-LE approach.