Load Factors for the Estimation of Internal Forces in the Stem of Cantilever Retaining Wall with Shear Key Under Seismic Loading

Abstract

Shear keys are placed beneath cantilever retaining walls to inhibit the sliding displacements in the wall thus increasing the demand of shear forces and bending moments in the stem of wall under seismic loading. In practice, design forces in walls are computed using conventional Mononobe-Okabe method which depends only on peak ground acceleration (PGA) of motion which does not represent characteristics of the earthquake motion. Earthquakes of different characteristics scaled to same PGA would ideally result in different internal forces in the system. The primary aim of the current study is to propose load factors accounting for these uncertainties associated with the variation in earthquake characteristics using LRFD technique. In view of this, non-linear FE dynamic analyses have been performed in OpenSees on the model of cantilever retaining walls with shear key and has been validated with experimental observations to obtain measured forces. The idea is to compute load factors by statistically correlating the forces predicted using conventional methodology with those from FE analyses and propose a simplified design methodology to account for the involved uncertainties associated with earthquake loading.