Application of power algorithm optimization for optimal placement of BRB in 3D shear wall frame building structure

Abstract

Abstract This paper examines the optimal placement, optimal numbers, and the optimal shape of Buckling Restrained Braces (BRB) for a 3D shear-wall frame building structure based on linear static analysis utilizing ETABS software. The total amount of BRBs referred to as the number of BRBs are considered as design variables and the objective function to be minimized is the maximum story displacement and inter-story drift. The diagonal shape (D), X-shape (X), V-shape (V), and Inverted V-shape (Inv-V) of BRBs are installed between shear walls simultaneously with initial stiffnesses of 1K0, 2K0, 4K0, and 8K0, respectively. Then, the performance efficiency analysis is carried out to identify the effectiveness of initial stiffness, BRB shapes, and optimal stories. Based on the results of the optimization procedure and efficiency analysis, it is found that the performance of the structure can be improved by optimizing BRB placement within the optimal stories rather than using the maximum amount of BRBs in all stories. The most optimal location to install BRBs is the middle stories and the BRB placement at the upper and lower stories is shown to have minor or no effects on reducing story responses of the structure. Furthermore, the model with Inv-V, V, and X shapes of BRB have almost the same maximum efficiency performance, while the model with diagonal shapes has the lowest performance efficiency. Additionally, the maximum performance of the structure can be achieved by using larger initial stiffness. The proposed method is further validated by comparing the results of ETABS with MATLAB programming. It concludes that the method proposed in this study saves 40% of the total amount of BRBs used in the structure by optimal placement of BRBs within the height of the structure. This method of optimization allows the structural designer to decide the optimal placement, optimal shape, and optimal stiffness of BRBs either by the predetermined performance level of the structure or based on experiences in RC shear wall-frame building structures.