ABSTRACT
Recent advances in performance-based seismic assessment and design of bridges call for the development of computationally efficient high-fidelity models for nonlinear transient dynamic analyses. A significant component of such models is that of the nonlinear lateral force-deflection of bridge abutment-embankment systems. In this study, we perform extensive parametric studies using a previously validated limit-equilibrium model, and aim to obtain a simple closed-form relationship for lateral response of abutment backwalls with uniform backfill. The resulting hyperbolic force-deformation (HFD) backbone curve has explicit dependency on the physical properties of the abutment system, including the backwall height. All input parameters to the HFD equation are measurable via standard geotechnical laboratory tests; and we demonstrate that the HFD formulas are valid for a broad variety of backfill materials. As opposed to limit-equilibrium models that produce only discrete data points on the backbone curve, the HFD equation can easily be implemented in a structural analysis package as a nonlinear spring that accounts for the bridge abutment-backfill interaction.
