Nonlinear dynamic analysis and seismic coefficient for abutments and retaining walls

Two-dimensional computational models of bridge abutment-soil systems are developed using the OpenSees framework. Nonlinear hysteretic behavior of backfill and foundation soil is simulated through a pressure-dependent nested yield surface plasticity model. Sliding and debonding at the soil-structure interfaces are simulated using node-to-node contact elements. Cantilever abutments and retaining walls of 6 m and 12 m height are analyzed using two recorded free-field accelerograms scaled for peak ground acceleration values of 0.12 g, 0.24 g, 0.36 g, 0.48 g, 0.60 g, and 0.72 g. Further, pseudo-static analysis using Mononobe-Okabe theory is carried out with varying seismic coefficients, and the results are compared with those of the dynamic analyses. Based on this comparison, recommendations are made for the value of seismic coefficient to be used in pseudo-static analysis so as to obtain results that are comparable to those obtained through a sophisticated nonlinear analysis. © 2013, Earthquake Engineering Research Institute.