Balanced Seismic Design of Anchored Retaining Walls

Abstract

Large permanent displacements of anchored retaining walls such as quay walls, sheet‐pile walls, and bulkheads are often reported in the literature after moderate to strong seismic activity. In most cases, liquefaction of the soil is cited as the reason for the large displacement or failures. In this paper, we examine an alternative mechanism, generated by inertial forces, which triggers large displacements of anchored retaining walls during moderate to strong earthquakes. Through this mechanism, we investigate whether substantial wall displacements or failures precede liquefaction. A limit equilibrium analysis, using the Mononobe‐Okabe seismic earth pressure equations, is performed to determine whether anchor failures lead to the general failure of anchored retaining walls during seismic events. Results of shaking‐table tests on aluminum walls with a dry cohesionless soil as the backfill confirm the analytical methodology. Based on the limit analysis, a balanced seismic design concept for anchored retaining walls is presented. We find that the balanced seismic design enhances the seismic resistance of anchored retaining walls at little additional expense. We use a typical design example to compare the balanced design procedure with current design practices.