Simultaneous optimization of brace locations and cross-sections of beams and columns of steel frames

This paper presents an optimization method of steel frames for minimizing the top displacement under seismic motions, where the thicknesses of columns, beams and braces are simultaneously adopted as design variables. By assigning a small lower bound for the thickness of braces, the locations of braces can also be optimized to find an optimal load path to transmit seismic loads to the supports. Seismic responses are evaluated using the response spectrum approach, and the results are verified using time-history analysis. Numerical examples are presented to demonstrate effectiveness of the proposed method to naturally generate a truss frame through optimization. © 2018 Architectural Institute of Japan. All rights reserved.