Optimal Design Of Semi-rigid Steel Frame With Bracing System Via Genetic Algorithm

As our country's economic strength and the development of steel production and the improvement of quality, more and more use of steel structure in the area of building structure. Steel structure has the advantages of high strength, light weight, construction speed and better seismic performance. In recent years the Ministry of Construction actively promote the domestic steel structure of the Research and Application.In many high-rise steel structures, steel frame system is a common structure. At present, it is common engineering practice to assume either pinned or fully rigid connections between beams and columns. But these assumptions for those who clearly showing a semi-rigid connections, will result in greater error. This paper first established a second-order nonlinear analysis program which can consider the semi-rigid connection, then the analysis of the deformation and internal forces under different stiffness and rigidity of the steel frame connecting shows that Semi-rigid connection to the internal force of the impact of significantly. Further, the calculation of the internal forces based on the traditional assumption is not applicable in fine design.In this paper, a genetic algorithm based optimum design method is presented for nonlinear multistory steel frames with semi-rigid connections, and comparison of optimum design result of the semi-rigid joints and rigid joint steel frame. This article discusses the differences of the optimal design of the results based the actual performance of the connection and the rigid assumption. Further, the results show that semi-rigid has great impact to the static properties of the frame structure. We must design based on the actual performance of connecting.With the increase of the high degree of high-rise steel frame structure, the design of bracing system becomes the key issues. In the paper, a genetic algorithm based topology optimization design of bracing system is presented for nonlinear multistory steel frames with semi-rigid connections. The Optimal design results show that we can get better arrangement of the bracing system, and get better economic results.