Seismic response modification device elements for bridge structures development and verification

Elements for modeling the behavior of seismic response modification devices were developed for use in analyzing bridge structures. Lead–rubber bearings and friction pendulum bearings (FPBs) with constant and variable friction coefficients were developed and verified against physical test data of structures using similar devices. The lead–rubber bearing element has a nonlinear elastic longitudinal spring, and a biaxial kinematic hardening spring in the transverse plane. The FPB element is formulated as a point to point contact element, including velocity and pressure dependent friction, and coupled vertical/horizontal displacements. The formulation and verification of the elements are presented here.