Enhanced Rao Algorithm-Based Optimization Method for Nonlinear Inelastic Steel Frames

Metaheuristics have been increasingly applied in structural design optimization due to their efficiency in finding the global optimal solutions. Several metaheuristic techniques have been proposed for the optimal design of structures. However, the performance of each method depends on the characteristic of the considered problem. Moreover, many metaheuristics require different control parameters to be tuned for their effectiveness. In this paper, we present a parameter-free metaheuristic based on the Rao algorithms to optimize steel frames. Direct analysis based on nonlinear inelastic analysis is utilized to capture the nonlinearity of material and structural geometry. The Rao algorithm, which is enhanced by an effective scheme to skip unpromising candidates without performing time-consumed nonlinear inelastic analyses, is used as the optimizer for the optimization. A two-story space steel frame is studied to show the effectiveness of the proposed method.