Reliability-Based Residual Service Life Assessment of CFRP-Strengthened Eccentrically Compressed Reinforced Concrete Columns Using Monte Carlo Simulation

The degradation of reinforced concrete (RC) structural members is a pressing global issue. Demolition is expensive, time-consuming, and can compromise adjacent members. Strengthening existing members using additional steel rebar, CFRP strip, RC, or ferrocement jackets offers a practical and modern alternative. At the same time, the durability assessment of such structures remains a critical problem. The article presents the results of improving the model for the reliability-based engineering assessment of the durability (residual resource) indicator of eccentrically compressed RC columns strengthened by CFRP under different load levels, and its calibration and internal validation using data from existing experimental studies. In addition to the set of strengths, geometric, and loading stochastic parameters, the improved model’s algorithm incorporates also the so-called “activation factor of the CFRP strip” – the empirical coefficient that represents the strip’s percentage of involvement in the strengthened column, with its value depending on the load level during strengthening and the strip’s cross-sectional area. The Monte Carlo method was applied to simulate and assess the strengthened column’s ULS reserve function, and the model algorithm’s implementation was performed using the Mathcad Prime software environment. The analysis of the obtained reliability and durability (residual resource) indices for the strengthened column samples showed convergence with similar values for the CC2 consequence class of designed structures, indicating the potential for further research in this field and the possibility of their use in reconstruction practice.