A Practice-Oriented Floor Response Spectrum Prediction Method for Seismic Design of Non‑Structural Elements

Abstract

This paper discusses the development of a practice-oriented method for the prediction of floor response spectra and seismic demands on non-structural elements to facilitate their design.

In New Zealand, the current building standards have been observed to provide inaccurate estimates of demands on acceleration-sensitive building components. The simplifying assumptions that underpin the code design approach for parts and components result in the over-prediction of demands on rigid short-period elements, under-estimation of the resonant behaviour of flexible non-structural elements interacting with the modes of the supporting structure, and the prescription of unrealistically large displacement demands for components with long periods.

Alternative prediction approaches recently proposed by the authors and others in the literature consider additional dynamic characteristics of both the non-structural element and the supporting structure, thereby improving the accuracy of demand estimates. This method, presented herein, explicitly considers the influence of nonlinear non-structural and inelastic structural behaviour. The approach has been extended for use with low-damage high performance structural systems, including base isolation and controlled rocking steel braced frames.

Consultation with practicing engineers in New Zealand is informing further refinement of a methodology for implementation in the New Zealand design standards. The goal of the new methodology is to achieve a suitable balance of simplicity and ease of use with improved specificity and accuracy, and possible means of achieving this are described.