ASTM D7337/D7337M-12 (R2019) PDF Download

The ASTM D7337/D7337M-12 (R2019) standard is a test method used for investigating the creep rupture of fiber reinforced polymer matrix (FRP) composite bars. This method is specifically designed for laboratory tests where the main variables include the size or type of FRP bars, magnitude of applied force, and duration of force application. Unlike steel reinforcing bars or prestressing tendons, the creep rupture of FRP bars can occur below the static tensile strength. Therefore, determining the creep rupture strength is crucial in assessing the acceptable stress levels for FRP bars used as reinforcement or tendons in concrete members that need to resist sustained loads. The creep rupture strength varies depending on the type of FRP bars being used.

The test method aims to measure the creep rupture time of FRP bars under controlled environmental conditions and force ratios. The data obtained from this test are used for material specifications, research and development, quality assurance, and structural design and analysis. The primary result of the test is the million-hour creep rupture capacity of the specimen. This standard is particularly relevant in design considerations for reinforced, post-tensioned, or prestressed concrete structures where the creep properties of FRP bars need to be taken into account. The test method provides guidelines for measuring the creep rupture of FRP bars used as reinforcing bars or tendons in concrete structures.