Parametric Study of Composite Beams under Fracturing Shear Connectors with Varying Parameters

Steel-concrete beams are widely used in highway bridges and are typically subjected to fatigue loads. A common failure scenario of such beams starts with the fracture of shear connectors in a progressive manner, which can significantly reduce their life span and cause a sudden failure of a bridge. This study estimates the residual strength of steel-concrete beams under the failure scenario of fracturing stud shear connectors combined with variations in selected parameters. The main objective of this study was to evaluate the effects of parameters such as the depth of the steel beam and external strengthening on mitigating the failure of shear connectors by increasing the load-carrying capacity of the steel-concrete beams. The study was conducted using an experimentally validated numerical three-dimensional finite element model. The results of numerical steel-concrete beams matched well with the beams tested experimentally. The effects of the various parameters were studied and compared. Both external strengthening and increasing the steel beam depth significantly increased the load-carrying capacity before the progressive failure of shear connectors. The combined use of external strengthening and increased beam depth gave the highest strength. The performance of each parameter varied as the progressive failure of shear connectors continued. Increasing the steel beam depth by 20% increased the load-carrying capacity by up to 23%.