Tensile resistance of J-hook connectors used in Steel-Concrete-Steel sandwich structure

• The tensile resistance of the J-hook connectors used in the steel-concrete-steel (SCS) sandwich structure with different concrete mixtures was experimentally investigated by carrying out 79 tensile tests.
• Theoretical models were developed to predict the tensile resistance of the J-hook connectors corresponding to different failure modes.
• An appropriate testing method was recommended to test J-hook connectors embedded in concrete core subject to tension pullout.
• A step-by-step design method was recommended to predict the tensile resistance of the J-hook connectors and determine the transverse shear resistance of the SCS sandwich beam with J-hook connectors.

Steel-Concrete-Steel (SCS) sandwich panel with ultra-lightweight cement composite core has been proposed to produce slim decking for bridge and building construction. One special feature of this lightweight sandwich panel is the use of J-hook connectors to improve the structural performance against combined actions of vertical shear and bending moment on the section. The proposed J-hook connectors provide effective bond between the steel and concrete, prevent local buckling and separation of the steel face plate, and enhance the transverse shear resistance to the structure. This paper investigates the tensile resistance of this new form of J-hook connectors by performing tensile tests on 79 sandwich specimens with various types of core materials including normal weight concrete, lightweight concrete, and ultra-lightweight cement composite. Their ultimate tensile resistances were obtained and corresponding failure modes were reported. The main parameters that influenced the tensile resistance of J-hook connectors were discussed and analyzed. Theoretical methods were developed to predict the tensile resistance of the J-hook connectors and their accuracy was verified against test results. Finally, recommended methods were proposed for design purposes.