Statistically Based Determination of Partial Safety Factors for FRP Bars

Abstract Fiber-reinforced polymer (FRP) bars used as internal reinforcement in concrete structures have gained renewed interest in recent years, primarily due to their high durability, particularly in aggressive environmental conditions. The adoption of FRP bars as an alternative to steel reinforcement effectively mitigates corrosion-related deterioration; however, it also raises concerns regarding the reliability and safety assessment of nonmetallic reinforcement systems. In recent years, substantial efforts have been devoted to developing and implementing design provisions for FRP-reinforced concrete members. In this context, the qualification of FRP bars in accordance with standardized procedures is essential for the reliable determination of partial safety factors within the semiprobabilistic framework adopted by modern design codes. Based on an extensive database of tensile test results on glass FRP straight bars, this study presents a comprehensive reliability-based assessment of partial safety factors. Material partial safety factors are derived using a code-based procedure. Both uncertainties in material properties and uncertainties related to resistance modeling and geometric variability are considered. Two alternative approaches to the treatment of these uncertainties are investigated: one employing separate partial factors for material and model uncertainties, and the other adopting a single resistance factor. The results contribute to the ongoing development of reliability-consistent design provisions for FRP-reinforced concrete structures and support the calibration of resistance safety factors for FRP bars within a European code–oriented framework.