A simple method to predict floor response spectral demands on nonstructural components

Abstract

This paper summarises a newly proposed practice-oriented method to predict elastic floor acceleration response spectra for estimating demands on nonstructural components. The approach builds on previous contributions in the literature, making specific recommendations to explicitly consider floor displacement response spectra, and to account for uncertainty in modal characteristics. The method aims to provide reliable predictions which improve on existing code methods, while maintaining simplicity to facilitate adoption in design and assessment. The method is verified against floor motions recorded in an instrumented building in New Zealand. This work is motivated by recent seismic events which have illustrated the significant costs that can be incurred following damage to secondary and nonstructural components within buildings, even where the structural system has performed well. Such observations have prompted increased attention to the seismic performance of nonstructural components with questions being raised about the accuracy of design floor acceleration response spectra used in practice. A comparison with existing code provisions from NZS1170.5, Eurocode 8, and ASCE 7-16 shows that the proposed approach performs well, particularly if a good estimate of the building's fundamental period of vibration is available. To illustrate its use with New Zealand standards, a design floor acceleration spectrum is computed at the NZS1170.0 and NZS1170.5 serviceability limit state.