Experimental Study On Longitudinal Shear Of Steel-Concrete Composite Beams

In the examinations of steel -concrete composite beams done by predecessors crack occurred early and the ultimate resistance reduced at certain extend. Transverse reinforcement has important influence on longitudinal crack. Through the study of examinations and finite element method, when transverse reinforcement is not enough composite beams of longitudinal singe stud are longitudinal splitting failure. Ones of longitudinal multi-rows studs are usually longitudinal shear failure. The reasons are different for two failure forms. But at time, composite beams of longitudinal double studs are not researched enough. In this paper, by eight steel-concrete composite beams and six push specimens, the effect of transverse reinforcement ratio and degree of shear connection and arrangement of studs on the mechanism of longitudinal shear failure and ultimate bending resistance are studies with emphasis. On the base of the study of examinations and finite element method, these conclusions are found: when transverse reinforcement is not enough, composite beams of longitudinal double studs are longitudinal shear failure. While, Ones of longitudinal single stud are longitudinal splitting failure. The two failure forms can reduce ultimate resistance of composite beams; Transverse reinforcement can affect the failure form of full-connection composite beams. When the transverse reinforcement ratio is larger than 0.60%,the failure form is bending failure. When it is litter than 0.41%, it is longitudinal shear failure. When it is in the zone of 0.41% and 0.60%, it concludes bending and longitudinal shear failure. The transverse reinforcement ratio is suggested larger than 0.60%; When transverse reinforcement ratio of part-connection composite beams is litter than 0.60%, if the total longitudinal shear is lower than it of concrete slabs the failure form is fracture of the shank of the stud, else longitudinal shear failure; By the test study of predecessors and this paper, the formula about longitudinal shear capacity in unit length when longitudinal crack occur is regressed; Softened truss model theory can be used to calculate longitudinal shear of composite beams of longitudinal double studs; Tow groups push specimens confirm the capacity of single stud in this test. The software ANSYS is used to simulate the performance of composite beams.