Simulation of the In-plane and Out-of-plane Seismic Performance of Nonstructural Partition Walls
AdvisorMaragakis, Emmanuel “Manos”
Civil and Environmental Engineering
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Although recent years have witnessed progress in the experimental and analytical simulation of nonstructural partition walls, a robust solution to prevent extensive damage to these walls has not been found. This is due in part to the lack of validated comprehensive analytical tools to better understand and simulate these walls. The current study supports this field of research through proposing a reliable generic method, for the first time, to analytically model the in-plane and out-of-plane seismic performance of partition walls with various configurations.Initially, a series of full-scale experiments is performed at the UNR-NEES site to investigate the system-level response and damage mechanisms of nonstructural systems, including cold-formed steel-framed (CSF) gypsum partition walls. The experiments reveal that the seismic performance of partition walls depends on the performance of the connections (e.g. gypsum board-to-stud/track connections) as well as the out-of-plane properties of the return walls. Accordingly, a series of component-level experiments (more than 130 experiments) is designed and conducted to characterize the cyclic response of the wall connections, namely gypsum board-to-stud/track, stud-to-track and track-to-concrete connections. The experimental data is used to propose and calibrate analytical nonlinear material models for the connections in OpenSees. Subsequently, the connection models are employed to propose a novel detailed and yet computationally efficient modeling methodology for nonstructural partition walls. In this methodology, the in-plane and out-of-plane nonlinear behaviors of the connections are represented by hysteretic load-deformation springs, which have been calibrated using the component-level experimental data. The steel framing members are modeled by nonlinear beam elements and the gypsum boards are simulated using linear four-node shell elements while. The representative models of corner connections are also assembled accounting for stud configurations, stud-to-stud and gypsum-to-stud screw attachments, and gypsum-to-gypsum contacts. The proposed procedure is used to generate analytical models of four configurations of experiments at the University of Buffalo as well as the analytical model of a C-shaped wall system, tested at the University of Nevada, Reno. Comparison of analytical and experimental results shows that the analytical model successfully estimates the force-displacement response, the out-of-plane dynamic characteristics, and the out-of-plane acceleration responses of partition walls. In addition, the model can predict the possible damage mechanisms in partition walls. The procedure proposed here can be adopted in future studies by researchers and also development engineers to assess the seismic performance of partition walls with various dimensions and construction details, especially where test data is not available.