Pros and cons of rotating ground motion records to fault-normal/parallel directions for response history analysis of buildings

Journal of Structural Engineering
By:  and 

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Abstract

According to the regulatory building codes in the United States (e.g., 2010 California Building Code), at least two horizontal ground motion components are required for three-dimensional (3D) response history analysis (RHA) of building structures. For sites within 5 km of an active fault, these records should be rotated to fault-normal/fault-parallel (FN/FP) directions, and two RHAs should be performed separately (when FN and then FP are aligned with the transverse direction of the structural axes). It is assumed that this approach will lead to two sets of responses that envelope the range of possible responses over all nonredundant rotation angles. This assumption is examined here, for the first time, using a 3D computer model of a six-story reinforced-concrete instrumented building subjected to an ensemble of bidirectional near-fault ground motions. Peak values of engineering demand parameters (EDPs) were computed for rotation angles ranging from 0 through 180° to quantify the difference between peak values of EDPs over all rotation angles and those due to FN/FP direction rotated motions. It is demonstrated that rotating ground motions to FN/FP directions (1) does not always lead to the maximum responses over all angles, (2) does not always envelope the range of possible responses, and (3) does not provide maximum responses for all EDPs simultaneously even if it provides a maximum response for a specific EDP.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Pros and cons of rotating ground motion records to fault-normal/parallel directions for response history analysis of buildings
Series title Journal of Structural Engineering
DOI 10.1061/(ASCE)ST.1943-541X.0000845
Volume 140
Issue 3
Year Published 2014
Language English
Publisher ASCE
Contributing office(s) Earthquake Science Center
Description Article 04013062; 14 p.
First page 1
Last page 14