Effect of friction coefficients and sliding surface radii on seismic behavior of a triple friction pendulum bearing


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Zulfakar M., Karakaş A. İ.

SELCUK UNIVERSITY JOURNAL OF ENGINEERING SCIENCES, vol.21, no.02, pp.44-51, 2022 (Peer-Reviewed Journal)

Abstract

Triple friction pendulum bearing (TFPB) is one of the seismic base isolation devices that are widely used for critical structures prone to severe earthquakes. Some important parameters affecting the seismic performance of a TFPB are effective radius and friction coefficient of sliding surfaces. These parameters need to be investigated parametrically to be able recognize their sensitivities on the efficiency of a bearing. Therefore, in this study, 10 TFPB models with different effective radii and friction coefficients are analyzed numerically. TFPB is modeled as an exact finite element in OpenSees program. The structure supported by the bearings is simply modeled as a mass resting on the TFPB. The bearing models are structurally analyzed using time history analysis method with two ground motion records selected from the PEER Strong Motion Database. The analytical responses of the bearings are obtained for maximum bearing displacements and base shear forces. Also, the hysteretic loops of bearings are acquired to investigate the effects of previously mentioned parameters on the performance of the TFPBs. As far as the numerical results are considered, it can be stated that the bearing displacement and base shear reduce as the radius of the sliding surface increases. On the contrary, when the coefficient of friction is increased, the bearing is subjected to greater base shear. The results also show that the area of the hysteresis loops of the TFPB with smaller effective sliding surface radius is larger. Thus, it can be concluded that the TFPB with larger effective sliding surface radii and smaller friction coefficients performs better for the earthquake motions considered in the present study.