Effect of the Bracing Types of Steel Framed Structures by Seismic Optimum Design

This study develops two algorithms for the design of braced steel frame structrues: the continuous and the discrete optimum design algorithms. For the seismic and wind design of structures, the time-history analysis of MDOF system is performed by the mode superposition method. In the optimization formulation, the objective function is the total weight of steel members and the design constraints are the ultimate strength requirements of LRFD 1994 code and the allowable story drift requirements of UBC code. In cross sectional design, the I-shaped built-up sections are used in the continuous optimization method and the W-shaped sections of AISC commercial products in the discrete optimization method. It was found from various examples of optimum design that the K-bracing is the most effective to resist the lateral seismic loads.