Performance-based sizing optimization method for steel frame structures

By modifying the sizing of the components, different performance levels can be achieved in the structure, thereby enabling a performance-based design for steel frame structures. In this paper, a performance-based seismic optimization design method for steel frame structures is presented. The combined response surface model is used to approximate the constraint and objective functions, and the optimal solution for sizing is obtained by continuously improving the response surface. In order to efficiently and accurately obtain the performance of steel frame structures, a simplified pseudo elasto-plastic analysis method based on the energy equivalence principle is proposed. This simplified method equates the energy of components in the elastic analysis process with that in the elasto-plastic state and derives the formula for the stiffness reduction factor, which describes the damage location and damage degree of the components under an earthquake. With the help of programming software, an optimization program for the performance-based design of steel frame structures was prepared to realize the automated calculation. The proposed optimization method was applied to four steel frames, demonstrating its ability to satisfy various performance targets while reducing material consumption. These results indicate that the performance-based design based on the combined response surface method and the pseudo elasto-plastic analysis method is feasible and effective.