Experimental Study and Numerical Study on Shear Bearing Capacity of Shear Key Joints of Reinforced Concrete Open-Web Sandwich Plates

The shear key in the reinforced concrete open-web sandwich plate (RCOSP) is a block joint that connects with the top chord and the bottom chord. In order to understand the failure mode of the shear key and verify the accuracy of the current algorithm, a total of 9 test pieces are prepared and classified 3 groups were assigned longitudinal reinforcement (LR) ratios of 0.49%, 0.82%, and 1.24%, respectively. The horizontal concentrated static loading under simple support condition is carried out. The test results show that the shear key is horizontally cut and the concrete is pulled apart or crushed along the direction of chord width at the shear key-chords area; the strain level of the concrete and stirrup of the shear key is lower averagely; the development of the horizontal displacement and the strain of the longitudinal bars of the test pieces goes through elastic, elastoplastic, and plastic stages; the ultimate load of the test pieces has almost no relationship with the reinforcement ratio of shear key but is controlled by the degree of crack development in the area where shear key connects with the chords. To avoid the current algorithm overestimating the shear capacity of shear key, the restricted condition of shear section is proposed. The finite element analysis (FEA) further verifies that the restricted condition of shear section proposed in this paper is reasonable and necessary.