Extreme modeling of triple friction pendulum isolator and its effect on behavior of superstructure

Document Type : Research Article

Authors

Amirkabir University of Technology, Tehran, Iran

Abstract

Sliding articulated isolators are well-known types of seismic control tools that extensive observations have shown their effective role in reducing seismic damages in structures. Although this tool significantly improves the performance of the structure at different seismic levels, but the existence of uncertainties in the limit behavior of this isolator in earthquakes with long return periods has attracted the attention of researchers in recent years to model their ultimate behavior. When the isolator reaches its displacement capacity, the sliding parts strikes the side edge of the sliding surfaces and the performance of the structure affects by this special condition. In this study, after implementing the equations governing the behavior of these isolators, we proceed to mathematically model their ultimate behavior and study its effects on the dynamic response of the superstructure. So, by designing and modeling a sample structure, we examine the superstructure dynamic response at different scales of several earthquake records. The results shows that the average ground acceleration at the beginning of the contact behavior under the studied records, is about 1.25MCE, the elastic base shear is about 0.48 superstructure weight and the maximum elastic drift of the superstructure is about 0.0038. By increasing the level of acceleration, the amount of base shear increases to the levels that the superstructure shows the nonlinear behavior. Also, by performing analysis on a model without ultimate behavior and comparing the results with the ultimate model, coefficients for converting the results of the non-ultimate model to the ultimate model are presented.

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