Test of Steel-Concrete Composite Girder with Stud-Epoxy Mortar Hybrid Connectors

The static loading test was carried out on six full-scale steel-concrete composite girders with stud-epoxy mortar hybrid connectors. The effect of the spacing between stud groups on the mechanical properties of composite girders was considered. The bearing capacity and the interface slip characteristics, as well as the shear force distribution sequence and the strain evolution of the bolts were analyzed and summarized. The results indicated that the epoxy mortar bonding layer bore the main shear force in the elastic stage. After entering the elastic-plastic stage, the stud began to bear the main shear force; in the failure stage, the interface sliding shift between the precast concrete and the steel beam should not exceed 2 mm at the loading point and middle position of the composite girders, indicating that there was a good cooperative work between the precast concrete slab and the steel beam. The residual flexural bearing capacity of composite girder was still more than 60%, which indicated that it had good ductility.When the spacing between the stud groups was reduced from 700 mm to 525 mm and 525 mm to 420 mm, the ultimate bearing capacity and the total energy consumption increased by 3.4% and 41.9%, 4.1% and 2.5%, respectively. Finally, based on the plastic theory, a formula for calculating the flexural bearing capacity of steel-concrete composite beams with hybrid connections was proposed.