Performance evaluation of cold-formed steel braced frames designed under current U.S. seismic design code

Abstract

The purpose of this study is to evaluate the seismic performance of cold-formed steel braced frames (CFSBF) by adopting a new evaluation procedure developed from the SAC Joint Venture. The validity of R factors for CFSBF in current U.S. design codes was examined. To estimate the global collapse drift capacity of CFSBF buildings the modified IDA procedure was used. Also, the values of some parameters were newly decided for CFSBF buildings. The two-, four-, and six-story prototype CFSBF buildings for the Seattle site were chosen for this study. The modeling of the braces and columns of CFSBF buildings was based on the results of static cyclic test and shaketable test conducted from CERL. Also, the gypsum walls' contribution to resisting lateral loads was considered for analysis. According to the evaluation results, the four- and six-story CFSBF buildings designed under current design codes were not able to satisfy the performance objective, so a new configuration scheme for CFSBF buildings exhibiting better seismic performance was proposed.