Evaluation of linear visco-elastic model of quintuple friction pendulum isolator

Abstract

Although nonlinear hysteretic model of the quintuple friction pendulum (QTFP) isolation system allow a detailed appraisal of response by means of nonlinear time-history analyses, such analyses are dilatory and not suitable for the early stages of design where appropriate configurations are required for the desirable performance. However, it would be favourable to have a linear visco-elastic model to determine peak dynamic response parameters at the preliminary design to achieve desirable performance. A comparative study of linear and nonlinear model of the QTFP depends upon equivalent effective stiffness and effective damping for seismic response quantities are presented. It is observed that the linear model gives consistently good and conservative estimate of peak isolator displacement and base shear whereas, it under-predicates the floor acceleration as compared to nonlinear model. Further, the effect of superstructure flexibility for both models is studied and linear model is found suitable for flexible superstructures too.