Abstract
This paper proposes a calculation methodology for composite steel-concrete orthotropic deck, adapted from the European design standards EN 1993-1-5, EN 1994-1-1, and EN 1994-2. The construction solutions analyzed include steel girders with a monolithic reinforced concrete slab cast over orthotropic plating, providing advantages such as increased bending and torsional stiffness, elimination of the need for bracing, and improved corrosion protection. The shear lag effect is evaluated at both serviceability (SLS) and ultimate limit states (ULS) using the models recommended by EN 1993-1-5. A case study illustrates the application of the method on a 38 m-span footbridge, where the effective plate width and the interaction between shear lag and local buckling are analyzed. Stresses due to concrete shrinkage, creep, and thermal effects are also considered. The results demonstrate that the entire plate width remains active, with negligible differences between effective and gross areas. The conclusions highlight the efficiency of the composite orthotropic solution in bridge design.