Optimal Topology Design of Bracing Systems for Multistory Steel Frames

Abstract

This paper presents a performance-based optimization method for optimal topology design of bracing systems for multistory steel building frameworks with overall stiffness constraint under multiple lateral loading conditions. Material removal criteria are derived by undertaking a sensitivity analysis on the mean compliance of a structure with respect to element removal. A performance index is proposed to evaluate the performance of resulting bracing systems in the optimization process. In the proposed method, unbraced frameworks are initially designed under strength constraints using commercial standard steel sections from databases. The optimal topology of a bracing system for the multistory steel building framework is then generated by gradually removing inefficient materials from a continuum design domain that is used to stiffen the framework until the performance of the bracing system is maximized. Two design examples are provided to illustrate the effectiveness of the performance-based design optimization method proposed for the conceptual layout design of lateral bracing systems for multistory steel building frameworks.