Topological optimization of composite trusses considering CO₂ emission via metaheuristics algorithms

Otimização topológica de treliças mistas considerando a emissão de CO₂ por meio de algoritmos meta-heurísticos

Abstract

In order to provide more sustainable solutions to the design of composite truss beams, the present work proposes a formulation to optimize dimensional, geometric and topologic parameters aiming to minimize CO₂ emissions. Genetic Algorithm (GA) and Particle Swarm Optimization (PSO) are used to solve the optimization problem considering the choice of steel profiles, characteristic strength of concrete, formwork, number of panels and truss total height. The methodology is applied to three problems where three different types of profile geometry and three models of truss are considered in order to compare and analyze its results. The program considers double angles, circular hollow tubes and circular concrete-filled tubes, as well as Pratt, Howe and Warren models. The three problems are identical, with the exception of the span size, varying between 8, 24 and 40 meters. In conclusion, results show the algorithms provide equal or similar solutions, with the Warren model and circular concrete-filled tube being the best solutions in all cases, especially for larger spans, reaching an emission reduction of up to 40% in relation to the Howe model using double angles. The critical criterion in the sizing of all cases attained a design-resistant effort relation greater than 90% in all cases, confirming the effectiveness of the optimization, being the combined criterion the critical in most of them.

Keywords:
optimization; composite truss; meta-heuristic algorithm; environmental impact; topological optimization