The tied-arched steel bridges represent an advantageous structural typology commonly used to build bridges of medium span length (around 100 and 200 m). The design concept with which modern steel arch bridges are built nowadays is a compromise between structural optimization and robustness. Structural optimization of the structure leads to the creation of increasingly lighter structures to minimize the use of the material. The structural robustness instead tends to design “redundant” structures that have sufficient resilience in dealing with extreme actions to avoid the progressive collapse of the structure. With the study made is possible to make interesting considerations on the concept of robustness and structural optimization of the bridge considered as case study and led to interesting ideas for increasingly cutting-edge designs that can pursue the objectives that are imposed on us by today’s society.