Calibration of the FRP Resistance Reduction Factor for FRP-Confined Reinforced Concrete Building Columns

This paper presents a reliability-based methodology for calibration of the fiber-reinforced polymer (FRP) resistance reduction factor used in the design of FRP-confined RC columns designed based on current guidelines. The Monte Carlo simulation technique was employed to generate a large population of design cases based on frequency of the design variables. Within the code calibration procedure, a comprehensive probabilistic study on variability of resistance, i.e., compressive strength of FRP-confined RC columns considering uncertainties in material properties, section dimension, and the model error, was carried out. It was shown that statistics of resistance and consequently reliability of the ultimate limit state are highly dependent on the variability of confinement model and the FRP strain efficiency factor. Furthermore, for RC columns with spiral confinement, the current FRP resistance reduction factor advised by current guidelines should be reduced. Sensitivity of the FRP resistance reduction factor to some selected target reliability indexes was also studied. In addition, a confinement-dependent formula for determining the FRP resistance reduction factor was proposed