Seismic Design of Steel Chevron and Split‐X Concentrically Braced Frames

ABSTRACT This paper aims to (1) investigate how various design parameters affect seismic response of steel chevron and split‐X braced frames, (2) advance understanding of their seismic behaviour and (3) propose new system‐specific guidelines for accurately estimating their seismic demands and for achieving enhanced seismic performance. Initially, 12 frames are selected and designed in accordance with Canadian design provisions. Frames are numerically modelled with a fibre‐based technique, and nonlinear response history analysis is performed to evaluate the effect of key design parameters on their seismic behaviour, including drift response, beam deflection, brace axial force, column moment demand and beam yielding. Subsequently, 380 additional frames are generated by adjusting the brace cross‐sections of the initial set. These frames are then dynamically analysed to develop mathematical expressions capable of predicting column flexural demands and identifying the location of drift concentration. Furthermore, design recommendations are proposed based on the results of dynamic analyses for accurately estimating beam demands in split‐X braced frames and in chevron braced frames with elastic and yielding beams.