Application of Monte Carlo-JC method to the reliability assessment of flexural capacity of RC beams strengthened with FRP

The JC method combined with Monte Carlo simulation procedure (called Monte Carlo-JC method) was applied to conduct a systematic reliability assessment of flexural capacity of FRP reinforced concrete beams designed by the report ACI 440.2R-02 (called ACI guideline). Several programs were made by utilizing the inherent random number generators of Matlab software. The results indicate that the concrete strength f' _c, CFRP reinforcement ratio ρ_f and CFRP mechanical properties are the most significant influencing factors on the mean values and the standard deviations of the strength ratio M/(M_n). The results show that the averaged reliability indexes decrease with increasing the resistance reduction factor  and load effect ratio L_n/D_n. The global reliability index for flexural design was found to be 4.40, based on all reliability indexes. The reliability level of ACI guideline is rather conservative. The resistance reduction factor  is suggested as a fixed value of 0.90, regardless of the strain level of the tensile steel reinforcement. ACI guideline is the most typical one among all current relevant guidelines. The reliability assessment of this guideline is of general significance.