Topology optimization of building bracing schemes

Abstract

The thesis presents a technique for producing economical solutions for conventional structural steel frames using topology optimization on the lateral bracing scheme. The study focuses mainly on minimizing the amount of material used and optimizing the placement of bracing elements in typical steel frame structures to achieve economical and realistic solutions. Linear structural analysis is performed on steel frame structures while considering static gravity and wind loading. The optimization scheme uses a "multi-level design" approach with two distinct optimization loops. The optimal beam and column sizes in a structural steel frame system are generated in the first optimization loop and a bracing removal criterion is derived in the second loop to optimize the lateral bracing topology. A space constraint is imposed on the steel frame structure to enable designers to specify large empty spaces. A performance index is proposed to compare the cost between structural steel frames designed using conventional approaches, which rely on engineering experience and trial-and-error, and the approach specified in this study, which uses a multi-step optimization scheme. Two case studies are made, comparing steel frame structures designed using the proposed method with one designed using the traditional method. Keywords: Topology optimization, steel frame optimization, space-constrained optimization, multilevel optimization