Salajegheh - Professor, Dept. of Civil Engineering, Shahid Bahonar University of Kerman, Kerman, Iran
Mohammadi - Graduate Research Assistant, Dept. of Civil Engineering, Islamic Azad University (Kerman Branch), Kerman, Iran
Ghaderi Sohi - Graduate Research Assistant, Dept. of Civil Engineering, Shahid Bahonar University of Kerman, Kerman, Iran

Earthquake and structural engineering challenge of creating optimized, reliable and cost effective structures leads to the combination of optimization and performance based seismic design theory. The prime goal is to automate the optimum design of the structure on the basis of performance based design and also considering the inherent uncertainties. In this study automating the design process of concentric steel braced frames is performed by use of genetic algorithms. The optimal design of structure minimizes the structural weight subjected to performance constraints on axial deformations of braces and plastic hinge rotation of beam - columns and also the force interactions relationships for them. Nonlinear static analysis (pushover) is implemented by considering the effect of post-buckling in compression brace elements and the performance based criteria is derived from the FEMA-356 (2000). The developed software in this study is capable of optimally automating the design of braced Frames with different spans and stories for a prescribed performance objective, with the limitation of usage for structures in which the first mode is dominant. It is found that a wide range of valid design alternatives exists, from which a decision maker selects the one that balances and optimizes different objectives in the most preferred way.

performance based design, optimization, pushover analysis, genetic algorithm