The development of revised effective slab width criteria for steel-concrete composite bridges

In design and analysis of steel-concrete composite girders, values of maximum deflection, stress and strength are typically obtained from simple beam theory by utilizing the effective slab width concept. Shear-lag effects are indirectly accounted for, by replacing the actual slab width by an appropriate reduced "effective" width. In this research, a new effective slab width definition is introduced. A three-dimensional non-linear finite element analysis is employed to evaluate and determine the actual effective slab width of steel-composite composite bridge girders. The resulting effective width is believed to be larger than the ones provided by many design specifications, both nationally and internationally. The revised effective slab width criteria based on the proposed effective slab width definition is compared with other design specifications, specifically AASHTO LRFD, British, Canadian, Japanese, and Eurocode design specifications. The comparative studies include the comparisons of service limit state, positive versus negative moment regions, and interior versus exterior girders of a multiple span continuous configuration.