Analytical evaluation of steel–concrete composite trussed beam shear capacity

A calculation method for the prediction of the shear resistance of precast composite beams, named Hybrid Steel Trussed-Concrete Beams (HSTCBs), is herein proposed. HSTCBs are constituted by a prefabricated steel truss embedded within a concrete matrix cast in situ so that, after curing, the two materials work together in the mechanical response of the composite structural element, the steel truss behaving as reinforcement of the beam. The proposed analytical model is developed on the basis of the results of a reference experimental campaign of three-point bending tests available in the literature, carried out on specimens of HSTCB designed in order to attain a shear failure. Furthermore, the proposed analytical formulation is supported by the outcomes of the finite element modeling available in the literature concerning the abovementioned reference tests. The model presents an additive formulation in which the shear resistance of the HSTCB consists of the contribution from concrete and shear reinforcement, being the diagonal rebars of the steel truss regarded as the stirrups typically present in Reinforced Concrete (R.C.) beams. Finally, also the contribution of the steel plate is taken into account in the resisting mechanism. Both reference experimental and numerical results are employed for the validation of the proposed analytical expressions and, with the aim of widening such a validation, also further experimental data available in the literature are taken into account, dealing with bending tests with shear failure on a similar typology of HSTCB.