Four-Element Pseudodynamic Hybrid Simulation of a Steel Frame with Cast Steel Yielding Connectors under Earthquake Excitations

Abstract

Cast steel energy dissipative components are increasingly being incorporated in structural systems in recent years. Cast steel yielding connectors (YC) demonstrate a stable symmetric hysteretic response with increased postyield stiffness at large deformations due to second-order geometric effects. In the present study, the seismic performance of a four-story steel structure equipped with cast steel YCs is investigated through pseudodynamic hybrid simulations using the University of Toronto 10-Element Hybrid Simulation Platform (UT10), where the structure is subjected to three maximum considered event (MCE)-level earthquakes. Four YCs in the seismic force–resisting system are represented physically, whereas the rest of the structure is modeled numerically. These experiments are performed as part of an initiative to produce a database of high-fidelity system-level benchmark test results and to critically study and improve existing numerical models, their calibration, and the loading protocols used in their calibrations. The experimental results can be used to study these aspects in the numerical models for YCs or systems with similar hysteretic characteristics. The hybrid simulations are followed by cyclic tests on two of the YCs to evaluate the remaining low-cycle fatigue life of the YCs and to provide information on the cumulative plastic ductility capacity of YCs.