A Novel DEM-Subset Simulation Approach for the Behavior and Reliability Calibration of FRP-Reinforced Concrete Beams

Fiber-reinforced polymer (FRP) bars are increasingly utilized to replace steel bars in concrete beams because of their chemical resistance, light weight, and high strength. Therefore, this paper develops a computational program based on a branch of discrete element method (DEM), namely, rigid body spring network, and subset simulation to simulate the behavior of FRP-reinforced concrete beams. Moreover, the reliability indices and the resistance reduction factor of FRP-reinforced concrete beams designed by ACI 440.1R-15 and by nonlinear analysis are also evaluated. In the numerical model, the constitutive laws of materials and the uncertainties of numerous random variables are considered. After verifying with results obtained from ACI 440.1R-15 and experiments, it is obvious that the proposed procedure can capture the behavior of FRP-reinforced concrete beams well in terms of load-carrying capacity, crack formation, and failure modes with the mean and CoV of only 1.037 and 0.052, respectively. The results of the study also show that the values of 0.68 and 0.75 corresponding to the target reliability indices of 4.0 and 3.5 can be taken for the design of FRP-reinforced concrete beams by nonlinear analysis.