Analysis on seismic responses of base-isolated structures with lead rubber bearings under biaxial ground excitations

The biaxial coupled visco-elasto-plastic differential restoring force model of lead rubber bearings is proposed, the comparing analysis on seismic responses of base-isolated structures with lead rubber bearings under uniaxial and biaxial ground excitations is carried out by the program of dynamic analysis on base-isolated structures ( DABIS). It is found that the structural accelerations and displacements under biaxial ground excitations are similar to that under uniaxial ground shaking, but the maximum displacements of the bearings under biaxial ground excitations is much lager than that under uniaxial component, so that the orthogonal effects of biaxial ground excitations should be considered to ascertain the maximum displacements of the bearings.