Seismic Analysis and Design of Bridge Abutments Considering Sliding and Rotation

Abstract

Current displacement based seismic design of gravity retaining walls utilizes a sliding block idealization and considers only a translation mode of deformation. However, recent studies demonstrate the possibility of seismic loss of bearing capacity and subsequent rotation or mixed mode of deformation. It has previously been proposed that this more complex scenario be described with coupled equations of motion cast in terms of relative acceleration between the retaining wall and the foundation soil. This report updates and extends the coupled equations of motion that appear in the literature. A newly developed fundamental theory on seismic bearing capacity of soils is used to compute the seismic resistance of bridge abutments and the resisting moment offered by the foundation soil. The equations presented are extended to consider the case of bridge abutments and load transfer from the bridge decks. (Adapted from authors' abstract).