Numerical calculation and analysis of mechanical properties of UHPC wet joint interface of prefabricated segmental beams

Prefabricated structure has already become the main body of future building constructions, however, weak shear resistance, joint interface easy to peel and poor durability of diamond wet joint of fabricated segmental beam is throughout a difficult technical problem. In order to solve that, a "? " (Chinese character) UHPC wet joint structure was designed. ABAQUS finite element software was used to analyze the effects of joint structure, joint reinforcement ratio and joint bond surface roughness on the mechanical properties of UHPC wet joint interface. The results shows that the finite element model based on "Traction-Separation " bond surface can better simulate the mechanical properties of wet joint interface of segmental beam. The interface mechanical properties of "? " joint proposed in this paper are significantly better than those of diamond joint; The tangential shear stress concentration area of the interface is much smaller than that of the diamond joint. The maximum peeling displacement of reinforcement and UHPC concrete in the tensile area of positive moment can be reduced by about 83.7 % " The interfacial bonding normal stress of "? " wet joint does not increase in the same proportion with the increase of reinforcement ratio, and the influence of reinforcement ratio on interfacial tangential shear stress shows a "bimodal " effect. In this paper, the reinforcement ratio of wet joint is recommended to be 4.8 %; Reinforcement ratio and interface roughness have little effect on the normal peeling displacement of wet joint interface, which can be ignored. China's "Code for design of concrete structures " considers the main shear action of stirrups in the structure, and its calculation results are the closest to the bonding shear strength of the concrete interface of this model.