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 (a_y); therefore, the present study shows an alternative approach to determining a_y 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 a_y for PS-LE methods is provided. The parametric studies illustrate that the DLO gives a higher acceleration (a_y = 0.271 g) than the LE method (a_y =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 (d_max=21cm) and FE (d_max=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.

Keywords:

• Quay wall
• limit analysis
• limit equilibrium
• discontinuity layout optimization
• yield acceleration
• permanent displacement
• performance-based design

Acknowledgement

The authors hereby appreciate the Sahel Consulting Engineers (SCE) for providing information relevant to this study.

Disclosure statement

No potential conflict of interest was reported by the authors.