RSAPS-BASED ISOLATION ELEMENT MODEL

To simulate the mechanical properties of seismic isolation bearings precisely, an isolation element model is developed based on the previously-built RSAPS simulation platform. The model combines the Bouc-Wen model that considers bi-lateral coupling effect with the two-spring model that considers vertical stiffness variation. The critical load at a given lateral displacement is determined using the overlapping area method. The loading/unloading condition is chosen depending on the isotropic behavior of the isolation bearing. A bi-lateral displacement-controlled test, a shaking table test of lead-rubber bearings under bi-lateral seismic excitations and a shaking table test of a scaled isolated bridge are simulated using the proposed model on RSAPS. The results show that the static and dynamic behavior of seismic isolation bearings can be simulated with high computational efficiency by the proposed model on RSAPS. The model can be applied to analyses of the seismic response of isolated bridge structures.