The problem existing in bridges that collapse due to undermining of the piers that sustain it, as well as collapses due to hydraulic action, generate high costs that can be reduced, making the repair of its structures. It is possible to reinforce them by modification, incorporating cable-stayed arches, and tensioning of hangers to support them. In this paper, a new approach is presented to solve the problem effectively, using a modern metaheuristic based on nature called monarch butterfly optimization it works imitating the way of migration, who uses the monarch butterflies. The results obtained are compared with those provided by black hole algorithm through the use of a known statistical test.