Evaluation of the shear connection strength of precast hybrid steel-trussed-concrete composite beams

In last decades, significant efforts have been carried out by the scientific community to evaluate the main technical issues of Hybrid Steel-Trussed-Concrete beams, investigating both the first opera-tive phase, i.e. before the concrete casting, when only the bare truss works, and, the second phase, i.e. after the concrete curing, when the beam works as a composite element. In the present study, the attention is focused on the evaluation of the shear strength of the connection between the bottom plate of the steel truss and the concrete core proposing a mechanical model able to predict its ulti-mate resistance. The proposed mechanical formulation is mainly based on the extension of existing formulations for the prediction of the resistance of steel dowels to the case of inclined steel bars loaded against concrete, accounting for the following effects: lateral and top confinement, mechan-ical non-linearities of materials, length of the plastic hinge arising on the steel bar and influence of moment-shear-axial force interaction effect. The accuracy of the model is verified with the experi-mental data collected from the technical literature and with Finite Element (FE) results obtained from a parametric analysis carried out by the same authors in a previous work.