Steel-concrete composite bridges are a popular solution due to the structural benefits of both steel and concrete. The typical system of a concrete slab and steel I-girders for small and medium-span bridges often displays the most economical results. However, other solutions emerge as innovative alternatives for bridge construction, such as composite beams with composite dowels and pre-cambered composite beams. This paper aims to develop a comparative study of these composite beam solutions to delimitate their efficiency, performance, and economy. Thus, a case study for the superstructure of a two-way simply supported railway bridge is detailed to define the composite beam’s performance indicators. The innovative alternatives presented benefits when compared to the traditional system, demonstrating the positive impact of their use on bridges.

This article presents numerical models for unbraced steel frames filled with structural masonry under cyclic loads, offering insights into their behavior and design potential. Using simplified micro-modeling in ABAQUS with the Concrete Damage Plasticity (CDP) model, the study accurately represents masonry interactions and shows strong agreement with experimental data (R² = 0.977). Results indicate that the fracture energy of laying joints and the friction coefficient between masonry and steel frames critically influence displacement, collapse mechanisms, and overall stiffness. Key findings reveal that the masonry infill increases frame stiffness by approximately ten times compared to the empty frame, reducing lateral deformations to less than 0.17% of the drift ratio. Masonry infills significantly enhance frame rigidity, acting as efficient bracing elements and reducing deformations, which is particularly valuable for seismic-resistant design. The research confirms the reliability of the CDP model for complex masonry behavior, validates simplified approaches for reduced computational cost, and highlights the need to incorporate friction effects in simulations. These findings provide a basis for future technical standards and offer practical strategies for engineers working with composite steel–masonry systems.