Coupled FDM-DEM simulations of axial compression tests on FRP-confined concrete specimens

Fiber-reinforced polymer (FRP) has been widely used in the repair and reinforcement of concrete structures. In this study, the finite different method (FDM) and discrete element method (DEM) are coupled to simulate the interaction between an FRP jacket and concrete specimen. Numerical axial compression tests on concrete confined by an FRP jacket are first implemented and analyzed. The mechanical performances considering the effects of micro-parameters are validated using laboratory axial compression tests on FRP-confined concrete specimens. The results show that the post-peak strength of FRP confined concrete is controlled by the ratio of the linear modulus to bond modulus, and the internal friction angle must be corrected during the continuous cracking of contacts; stress accumulates from the end to the center of a specimen and the confined radial stress is about a quarter of the axial pressure; and the level of contact crack can be quantified in the mesoscale, in which the stronger the cracking resistance, the thicker the corresponding jacket, and the greater the compression strength.