Tensile resistance of novel interlocked angle connectors used in steel-concrete-steel sandwich structures

The mechanical performances of steel-concrete-steel (SCS) sandwich structures were generally governed by the interfacial bonding between steel and concrete provided by shear connectors. This paper aims to propose a new interlocked angle connector (IAC) for sandwich structures to enhance the steel-concrete interfacial bonding performances, and its tensile behaviors were also experimentally and analytically studied in detail. There were 14 specimens with different parameters being designed and tested, and the different confinement effects of concrete around IACs were also considered in this study. The experiments revealed three failure modes of IACs embedded in concrete, i.e., concrete breakout failure, tensile fracture failure of the steel angle and concrete direct shear failure. The evident influences of confinement effect of concrete on the failure modes and tensile resistances of IACs were also observed. In addition, the tensile resistance of IACs was found to be significantly improved with the increasing of embedded depth of IACs and thicknesses of steel sheet. Analytical models were proposed for predicting the tensile resistances of IACs, and the predicted values showed a good match with the test results. Moreover, the tensile resistances of IACs were compared with those of existing semi-direct-link connectors, and the proposed IACs provided 55.9% higher tensile resistances than the existing semi-direct-link connectors. Thus, the steel-concrete interfacial bonding performances of SCS structures with IACs would be significantly enhanced. In subsequent studies, the mechanical performances of IACs under the combined actions of tension and shear should be concerned.