Modeling Reinforced Concrete Moment Frames Supported on Quintuple Friction Pendulum Bearings for Nonlinear Response History Analysis

Base isolation systems have attained significant advancements over the past several decades, with new technologies being developed to enhance the performance of structures when subjected to moderate and severe seismic excitations. The multi-stage friction pendulum is among the most efficient systems owing to its broad range of effective pendula with several regimes that provide excellent energy dissipation abilities. Lately, a new generation of friction pendulum bearings called "Quintuple Friction Pendulum" was introduced to the literature and has since gained the attention of researchers. This isolator's most significant advantages are the results of its capability to achieve multi-stage adaptive behavior which shows high energy dissipation capability from structures exposed to horizontal forces. Indeed, investigations that outlined the process for nonlinear modeling of structures supported on this type of isolation system are scarce. Thus, this research is intended to illustrate and discuss the approach for developing seismic code compliance finite element models for designing and analyzing reinforced concrete moment frames supported on quintuple friction pendulum bearings for nonlinear response-history analysis in OpenSees and SAP2000. As a part of the study, the nonlinearity of the isolation system and the superstructure will be considered. Moreover, the methods for overcoming essential issues such as damping leakage and isolator's stiffness correction will be discussed. In general, the results of the discussed numerical examples have shown that both finite element packages are capable of achieving QFP hysteresis behavior as well as computing similar superstructural responses. Furthermore, the illustrated method of overcoming damping leakage provided reliable outcomes compared to the theoretical expectations. As well as the suggested approach for correcting the isolator's initial stiffness was helpful in terms of accurately capturing the structure's periods.