Shear Capacity Model of Prefabricated Shear-Keyed Tooth Joints Under Confining Stress

Shear-keyed tooth joints (SKTJs) are commonly used in prefabricated buildings, including wind turbine foundations, to connect prestressed modules. Due to the significant loss of prestress in precast wind turbine foundations, slip failure is more likely to occur than shear failure. In this paper, a predictive model for SKTJs under small confining stress based on the ultimate limit state theory is proposed. The effects of the number of shear keyed teeth, reinforcement, and confining stress on the shear capacity of SKTJs are analyzed numerically. The incremental coefficient, i.e., the ratio of the shear strength increment to the product of the shear strength and the joint’s positive stress corresponding to the compression-shear state is illustrated theoretically and suggested to be 0.228, conservatively. A reduction factor is suggested for multi-keyed joints, and the contribution of reinforcement to the shear capacity is around 5%. Small confining stress results in slip failure, while large confining stress slows down the degree of shear failure. There is a positive correlation between the shear capacity under slip failure and the confining stress. Finally, the predictive model is validated by simulating the results of slip and shear failures.