The use of steel-concrete composite systems has been increasing over the past decades. Among the existing systems, steel-concrete tubular composite trusses stand out for their ability to span longer distances with reduced mass compared to full-web beams. The aim of this study is to present a multi-objective formulation for the topological optimization of steel-concrete tubular trussed beams, considering the possibility of filling the upper chord with concrete. The problem was modeled using bar elements with two degrees of freedom per node. The objective functions considered were CO₂ emissions, energy of fabrication process, and the load-bearing capacity of the truss, while the constraints were based on the requirements of Brazilian standards for laminated and tubular profiles. To solve the optimization problem, Multi-Objective Particle Swarm Optimization (MOPSO) was employed to generate Pareto fronts. The formulation was validated and compared with examples from the literature in which single-objective optimization of CO₂ emissions in beams was performed. Preliminary results indicate that the algorithm was effective in determining solutions when compared to the single-objective approach and led to more efficient structural systems, with increased load-bearing capacity and minimal CO₂ emissions and energy
