Scaling legitimacy for design of lead rubber bearing isolated structures using a bounding analysis

Abstract

In dynamic analyses, although there is no limitation for scale factors, the customary values vary from 0.25 to 4. However, these values are based on subjective judgments rather than a quantitative evaluation. This study focused on scaling legitimacy of acceleration time series to be used in dynamic analyses performed during the design of lead rubber bearing (LRB) isolated structures, to obtain a limit for scale factors. For this purpose, several dynamic analyses are performed with the parameters, namely, isolation period, peak ground velocity, and site class. In the analyses, a recently proposed deteriorating hysteretic bilinear representation is used to model the behavior of LRBs. Limitation for scale factors is discussed through the concept of bounding analysis that intends to provide design envelopes for response quantities of isolated structures. As a result, limits for scale factors, providing that the bounding analysis fulfills its intended purpose in design of LRBs, are proposed.