SHEAR PERFORMANCE TEST AND BEARING CAPACITY CALCULATION OF COMPRESSIVE COMPOSITE SHEAR CONNECTOR

A compressive composite shear connector with transverse studs is developed for steel-concrete composite structures with high shear resistance. Ten compressive composite shear connectors and one non-compressive composite shear connector were designed, and monotonic push-out tests were carried out. The effects of concrete bearing at the end of rib plate, concrete strength, rib thickness, rib hole diameter and stud diameter on the failure mode and failure process of compressive composite shear connectors were investigated. The finite element models of compressive composite shear connectors were established. Using the simulation model verified by experiments, the shear mechanism of compressive composite shear connector was further revealed. Based on the test variables, 108 finite element models of compressive composite shear connectors were established and analyzed, the linear relationship between the ultimate bearing capacity of compressive composite shear connectors and various parameter variables was deduced, the analysis results of ultimate bearing capacity were regressed, and the calculation model of ultimate bearing capacity of compressive composite shear connectors was proposed. The results show that the failure modes of concrete slabs of compressive composite shear connector are large-area vertical cracks and end cracks, and inclined main cracks extending downward from near the height of welding nails are formed on the inner surface. The concrete slabs with non-compressive composite shear connector have no obvious end cracks, and the ultimate bearing capacity of compressive composite shear connector is about 1.4 times that of the no-compressive type. Compared with the diameter of rib and stud, the ultimate bearing capacity of compressive composite shear connector is more sensitive to concrete strength and rib thickness. The proposed model of ultimate bearing capacity of compressive composite shear connector has clear physical meaning, and the calculated results are in good agreement with the simulation and test results, which can provide a reference for the design and engineering application of composite shear key.