en Optimal design Optimal design پژوهشي Research <span style="font-size:11.5pt"><span style="text-autospace:none"><span new="" roman="" style="font-family:" times="">The main objective of this paper is to optimize the size and layout of planar truss structures simultaneously. To deal with this challenging type of truss optimization problem, the center of mass optimization (CMO) metaheuristic algorithm is utilized, and an extensive parametric study is conducted to find the best setting of internal parameters of the algorithm. The CMO metaheuristic is based on the physical concept of the center of mass in space. The effectiveness of the CMO metaheuristic is demonstrated through the presentation of three benchmark truss layout optimization problems. The numerical results indicate that the CMO is competitive with other metaheuristics and, in some cases, outperforms them.</span></span></span><br> &nbsp; seismic performance level, steel moment resisting frame, neural network, feed-forward back-propagation. 173 187 http://ijoce.iust.ac.ir/browse.php?a_code=A-10-66-400&slc_lang=en&sid=1 S. Gholizadeh s.gholizadeh@urmia.ac.ir 180031947532846002494 180031947532846002494 Yes Department of Civil Engineering, Urmia University, Urmia, Iran C. Gheyratmand 180031947532846002495 180031947532846002495 No Department of Civil Engineering, Urmia University, Urmia, Iran