Evaluation of Seismic Design Criteria for Sliding Objects in Nuclear Facilities

Abstract

Sliding is recognized as a dominant response mode for unanchored stocky components in nuclear facilities. Although unanchored components are themselves not safety-critical, their interaction with safety-critical systems and components during earthquake shaking can have significant consequences. It is therefore important to be able to accurately estimate the peak sliding displacement demands on unanchored components so that sufficient clearance is provided around them. In lieu of nonlinear time history analysis, the ASCE/SEI 43-05 standard provides an approximate method to estimate the maximum sliding displacement of sliding objects in nuclear facilities. The present paper assesses the procedure of the approximate method and compares its results to those of nonlinear time history analysis. The study finds that the ASCE 43-05 approximate method provides conservative sliding estimates overall and that is based on the three components of 7 modified and 159 real earthquake motions used in this study. It is concluded that the ASCE 43-05 approximate method offers reasonable sliding estimates of components in nuclear facilities.