PERFORMANCE-BASED SEISMIC FAILURE MODE IDENTIFICATION AND OPTIMIZATION FOR STEEL FRAME STRUCTURES

Two performance indices, i.e. damage index and hysteretic energy dissipation index, are defined in this paper, and the performance-based structural failure mode identification method for steel frame structures is proposed based on the incremental dynamic analysis (IDA) method. The multi-objective optimization method of structural failure modes is developed using those two performance indices as the objective function and the section dimension of members as the variables. A numerical example of a 20-story benchmark steel frame structure is analyzed to identify and optimize its failure modes subjected to various earthquakes. Results indicate that the failure mode of structure subjected to the most unfavorable earthquake can be effectively identified through the performance-based identification method using the damage and hysteretic energy dissipation indices as evaluation functions, and the seismic behaviors of structure can be significantly improved by the performance-based multi-objective optimization method.