Seismic Displacement of Broken-Back Gravity Quay Walls

Abstract

Quay walls are one of the key elements of port and harbor facilities; however, their collapse and unexpected displacements during earthquakes have caused disastrous damage and economic consequences. Therefore, adequate design and assessing the seismic performance of waterfront quay walls continues to be a concern to the waterborne transportation industry. In this paper, the seismic displacement of broken-back quay walls is studied through eight reduced-scale shaking table model experiments. The experimental results indicate that backfill settlement is smaller in a region behind a broken-back quay wall in which coastal and port facilities located in this area would undergo less deformation and damage during earthquakes. The observations from the model tests also show that for walls on loose seabed materials, seabed softening may significantly contribute to quay wall horizontal displacement, and rotation. Moreover, the sliding displacements estimated using an improved sliding block model that incorporates the pseudostatic method of Mononobe-Okabe for lateral earth pressures, agree well with quay walls’ sliding displacements measured in the shaking table model tests.