Relative story displacements and torsional effects caused by strength variations in concentrically braced frames

Abstract

This study will investigate the accidental torsional response in steel structures designed by CBFs due to the variation in strength of braces under strong earthquake ground motions. For this study, it is assumed that the variation in strength of braces would come from the expected yield stress (RyFy) rather than minimum specified yield stress (Fy) of brace member. For this purpose, inelastic torsional response of a three and nine-story building having perimeter CBFs having various brace strength configurations subjected to strong earthquake ground motions is investigated in detail. The results are presented in the form of base shear vs. roof displacement (pushover curve, capacity curve) and drift ratio through nonlinear dynamic response analyses.