Preliminary Analysis of Isolated Raised Floors

To protect the non-structural components in critical facilities (such as hospitals), focusing in particular on the key sensitive components on the floor of a room, the combined solution of stiffening the structure and isolating the floor is proposed. One-story and three-story stiffened shear frames were considered as examples for the purpose of conducting different analyses. Models for each analysis case, both coupled and uncoupled models, were set up in SAP2000, and subjected to three spectra compatible acceleration time histories generated by using the TARSCTHS code. ISO-Base platforms by WorkSafe Technologies were selected as the isolators of interest in this early phase of the project. The preliminary analysis results show a decrease of the relative displacement of the isolated raised floor with respect to the corresponding base frame floor, and an increase of the lateral deformation of the base shear frame floor, when the isolated raised floor mass is increased. A theoretical explanation for the results is provided for the observed trends. The limited comparison of the analysis results between the coupled model and uncoupled model indicates that the uncoupled model results are conservative and could be used for the design of isolated raised floors. _____________ S. CUI, Multidisciplinary Center for Earthquake Engineering Research (MCEER), Department of Civil, Structural and Environmental Engineering, University at Buffalo, The State University of New York, Buffalo, New York. M. BRUNEAU, Multidisciplinary Center for Earthquake Engineering Research (MCEER), Department of Civil, Structural and Environmental Engineering, University at Buffalo, The State University of New York, Buffalo, New York.