Game-Theory-Based Multi-Objective Optimization for Enhancing Environmental and Social Life Cycle Assessment in Steel–Concrete Composite Bridges

The design of bridges must balance sustainability and construction simplicity. A game-theory-based optimization method was applied in this research to find a sustainable steel–concrete composite bridge design. The sustainability was evaluated through cost and environmental and social impact using the Life Cycle Assessment method. The optimization process considered four criteria simultaneously, using a discrete version of the SCA algorithm and a transfer function for discretization. The preferred solutions were selected using the Minkowski distances approach. Results showed a decrease in slab reinforcement and an increase in the amount of steel in the cross-section, leading to only an 8.2‰ increase in cost compared to similar studies. Regarding the cross-section, the geometry obtained considers cells in the upper and lower parts of the webs to improve the bending resistance. The proposed method allows for the simultaneous optimization of multiple criteria and provides a sustainable yet simple bridge design solution.