Equivalent-Linear Seismic Response of Bridge Approach Embankments

December 10, 2020

A single degree of freedom system model, called 1ME, is presented in this paper for calculating the seismic response of approach embankments in the far field. The model is developed using shear wave propagation theory, the Galerkin method and the fundamental mode of vibration of a uniform embankment. The non-linear response of the embankment is approximated with an equivalent-linear analysis using conventional shear modulus reduction and damping ratio curves. A simple expression for the effective cyclic shear strain of the embankment is developed for determination of the equivalent-linear shear modulus and damping ratio. A step-by-step procedure is presented for calculating the equivalent-linear properties and the seismic response of the embankment using an input earthquake record or a target response spectrum. Verification of the proposed model is carried out with finite element dynamic analysis. Accurate results are obtained with the 1ME model for calculating the far-field embankment response. Carvajal, J.-C., W.D.L. Finn and C.E. Ventura. 2016. “Equivalent-Linear Seismic Response of Bridge Approach Embankments,” in GeoVancouver 2016: 69th Canadian Geotechnical Conference, Vancouver, BC, October 2-5, 2016. Canadian Geotechnical Society.