Cyclic Performance of a Lightweight Rapidly Constructible and Reconfigurable Modular Steel Floor Diaphragm

Abstract

One approach to making modern structures more economically and environmentally sustainable is designing and constructing them to be adaptable to rapidly changing markets and building occupancies. At the same time, these structures are required to be resilient to seismic events. As a step towards meeting these goals, a lightweight, two-way, rapidly constructible and reconfigurable modular steel floor (RCRMSF) system has been developed. The system is fabricated from light-gauge steel plates sandwiching a grillage of orthogonally arranged cold formed Z-purlins, can span 9.1 m x 12.2 m, requires only girder supports, and fits within current steel construction framework. This study investigates the seismic behavior of the RCRMSF diaphragm through the use of high fidelity nonlinear finite element (FE) models. Six full-scale cantilever diaphragm models have been developed to study the effect of varying RCRMSF configurations and end support details. Both monotonic and cyclic loading protocols are used to determine the stiffness, strength, energy dissipation capacity, and general hysteretic behavior of the diaphragms. Based on the FE models, the behavior of the RCRMSF diaphragm is influenced primarily by the plate thickness and perimeter connection detail to the supporting steel frame. Overall, the RCRMSF has adequate diaphragm stiffness and strength, and shows favorable energy dissipation capacity due to its post-peak inelastic behavior. This observation implies that the RCRMSF can serve as an alternative solution to current seismic design and construction practices.