en Optimal design Optimal design پژوهشي Research This study is devoted to seismic collapse safety analysis of performance based optimally seismic designed steel chevron braced frame structures. An efficient meta-heuristic algorithm namely, center of mass optimization is utilized to achieve the seismic optimization process. The seismic collapse performance of the optimally designed steel chevron braced frames is assessed by performing incremental dynamic analysis and determining their adjusted collapse margin ratios. Two design examples of 5-, and 10-story chevron braced frames are illustrated. The numerical results demonstrate that all the performance-based optimal designs are of acceptable seismic collapse safety. optimization, performance-based design, chevron braced frame, incremental dynamic analysis, collapse margin ratio. 33 45 http://ijoce.iust.ac.ir/browse.php?a_code=A-10-66-329&slc_lang=en&sid=1 M. Ghasemiazar 180031947532846002646 180031947532846002646 No Department of Civil Engineering, Urmia University, Urmia, Iran S. Gholizadeh s.gholizadeh@urmia.ac.ir 180031947532846002647 180031947532846002647 Yes Department of Civil Engineering, Urmia University, Urmia, Iran