Numerical Study on Performance of Single-Keyed Epoxy Joint of Ultra-high Performance Concrete (UHPC) Under Combined Shear and Torsion Load

Under the vehicle load, segment joints are subjected to coupling effects of bending, shear, and torsion, while epoxy joints are mainly subjected to a combination of shear and torsion, making them more prone to failure. In this study, to investigate the torsion-shear performance of single-keyed epoxy joints of ultra-high performance concrete (UHPC), a refined finite element model (FEM) was carried out considering the effect of confining pressure in this study. The results of FEM indicated that the increase of confining pressure can effectively improve the shear-torsional load capacity of the epoxy joints. Whereas the increase of confining pressure has little effect on the improvement of stiffness. However, in view of the high confining pressure (when the confining pressure is greater than 18 MPa), the damaged surface of the specimen changes from the root of the male key to the feminine key.