Simulation of the In-plane and Out-of-plane Seismic Performance of Nonstructural Partition Walls

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

Seismic response assessment of architectural non-structural LWS drywall components through experimental tests

A research project was conducted at University of Naples “Federico II” over the last few years with the aim to give a contribute to overcome the lack of information on seismic behaviour of architectural non-structural lightweight steel (LWS) drywall components, i.e. indoor partition walls, outdoor façades and suspended continuous ceilings. The tested non-structural components were made of LWS frames sheathed with gypsum-based or cement-based boards. The research activity was organized in three levels: ancilliary tests, component tests and assembly tests. Ancilliary tests were carried out for evaluating the local behaviour of partitions, façades and ceilings. Component tests involved out-of-plane quasi-static monotonic and dynamic identification tests and in-plane quasi-static reversed cyclic tests on partitions. Finally, the dynamic behaviour was investigated through shake table tests on different assemblages of partitions, façades and ceilings. The study demonstrated that the tested architectural non-structural LWS drywall components are able to exhibit a very good seismic behaviour with respect to the damage limit states according to the IDR limits given by Eurocode 8 Part 1. The current paper describes the complete experimental activity within the project

Evaluation of seismic dynamic behaviour of drywall partitions, façades and ceilings through shake table testing

Significant damage to architectural non-structural components caused by recent seismic events highlighted their importance in the building design and showed that their damage or collapse might have severe consequences. Therefore, the study of the seismic behaviour of non-structural components is very important to minimize the risk. In this context, a specific research project aimed to improve and expand the knowledge of seismic response of architectural non-structural lightweight steel drywall components started at the University of Naples “Federico II”. This paper presents the results of dynamic shake table tests performed on prototypes made of indoor partition walls, outdoor façade walls and suspended continuous ceilings. The influence on seismic response of prototypes from basic and enhanced anti-seismic solutions, corresponding to the use of fixed or sliding connections at the walls and ceilings perimeter, was investigated. The seismic performance in terms of damage occurrence was also evaluated by fragility curves, which showed a better seismic response of enhanced solutions than basic solutions and a seismic “fragility” of indoor partition walls higher than that of outdoor façade walls. Finally, a repair cost estimation was performed by highlighting that the repair cost of partitions is higher than that of façades