Faramarz Khanmohammadi - Under graduate student, Department of Civil Engineering, Urmia University, Iran
Changiz Gheyratmand - Assistant Professor, Department of Civil Engineering, Urmia University, Iran
Saeed Tariverdilo - Associate Professor, Department of Civil Engineering, Urmia University, Iran.

Optimization is the foundation of all scientific and daily activities. As we know, the purpose of optimum design in engineering is choosing the best design among all acceptable designs. In this study the optimal design of a ten-story frame under the stress and displacement constraints based on the AISC-ASD specifications and Iranian code of practice for seismic resistant design of buildings is performed. And the results are compared with results obtained from the optimal design of that frame under the frequency constraints of the frame. The chosen frequency constraints are the frequency of the first three modes of the frame that is optimized under the stress and displacement constraints. To perform the optimization the particle swarm optimization algorithm (PSO) is used. Finite element analysis software ANSYS for modeling and analysis of the structures and also mathematical software MATLAB for optimization process are used

Optimization, steel frame, stress and displacement constraints, frequency constraints, Particle Swarm Optimization Algorithm