en Optimal design Optimal design پژوهشي Research The present work reveals a problem formulation to minimize material consumption and improve efficiency of diagrids to resist equivalent wind loading. The integrated formulation includes not only sizing of structural members but also variation in geometry and topology of such a system. Particular encoding technique is offered to handle practical variation of diagrid modules. A variant of <em>Pseudo-random Directional Search</em> is utilized to solve this problem treating a number of three dimensional structural models. Several issues are investigated including the effect of variation in the building height, its aspect ratio and fixing or releasing diagrid angles. Consequently, especial trend of variation in diagrid angle is observed with superior structural responses with respect to sizing designs of the fixed-angle modules. tall building, structural design, non-uniform diagrid modules, layout optimization, pseudo-random directional search, swarm intelligence. 15 32 http://ijoce.iust.ac.ir/browse.php?a_code=A-10-66-328&slc_lang=en&sid=1 M. Shahrouzi shahruzi@khu.ac.ir 180031947532846002941 180031947532846002941 Yes Civil Engineering Department, Faculty of Engineering, Kharazmi University, Tehran, Iran A. Azizi 180031947532846002942 180031947532846002942 No Civil Engineering Department, Faculty of Engineering, Kharazmi University, Tehran, Iran