FINITE ELEMENT FORMULATIONS FOR FRICTION PENDULUM SEISMIC ISOLATION BEARINGS

In this paper, an advanced analytical model and Þnite element formulations including local bending moment e¤ects for the Friction Pendulum System (FPS) are presented. Some important Þndings in these investigations reveal that local bending moments which result from the movements of the isolator, should be accounted for in the engineering design. The results presented in this paper show that if the e¤ects of local bending moments are excluded from design considerations, it may endanger structures during earthquakes. The new formulations considering local e¤ects provide an e¤ective tool to simulate the behaviour of FPS-isolated structures subjected to earthquake loadings. The proposed formulations can be applied directly for both two- and three-dimensional analyses without any further assumption. It is easy to implement the proposed techniques in existing Þnite element programs. The results obtained from the numerical analyses suggest that the local bending moment e¤ects are of signiÞcant importance, and should be taken into account to assure the safety of isolated structures during earthquakes