Prediction of the creep rupture strength of GFRP bars

Abstract The experimental portion of this study presents the results of an investigation into the unconditioned creep rupture strength of two different types of 12.7 mm GFRP bar both made with vinylester resin and ECR glass fibers but with different surface enhancements. An overview of the behavior and performance of FRP composites and bars under sustained load is discussed to determine whether a statistically-based empirical approach represents a viable method for the definition of a safe value of creep rupture strength. A refined approach to data handling and the extrapolation of a safe value of creep rupture strength is discussed, including statistical considerations. Results show that the creep rupture knock-down factor prescribed by current design guidelines is conservative when designing using the GFRP bars considered in this study. The surface preparation of the two types of GFRP bar has an effect on their tensile strength, but no additional influence on their creep rupture performance.