Sahand Sarioletlagh Fard - Faculty of Civil Engineering Islamic Azad University – Firouzkooh Branch,
Faraz Akbari - M.Sc Islamic Azad University - Science and Research Branch

The realistic modeling of beam-to-column connections plays an important role in the analysis and design of steel frames. A genetic algorithm based optimum design method used for nonlinear multistory steel frames with semi-rigid connections. The mentioned algorithm is employed as optimization method which utilizes reproduction, crossover and mutation operators.The design algorithm obtains a frame with the least weight by selecting appropriate sections such as wide flange steel sections of AISC standard.Finally, allocated semi-rigid connection stiffness to the beam-column connection would be obtained. During the procedure of optimization the amounts of these rigidities create by genetic algorithm in order to reach the minimum weight of frames. To perform modal analysis, linear static and non-linear static operations as well as design of elements, SAP2000 software and to perform the optimization procedure, the program written in MATLAB software domain have been used.Displacement and stress constraints of AISC-Load and Resistance Factor Design (LRFD) specification and also size constraints for beams and columns are imposed on the frame.Furthermore, the P−Δ effect is also accounted for in the analysis and design of the multistory frame. The result of this research was compared with result of previously published paper in this field

Genetic Algorithm ,None Linear , Semi-rigid Connection, Time History Analysis, Plastic Hinge