What is the Fatigue and Stress/Strain Relationship?
The University of Arkansas test report was based on several hundred tests for which stress/strain curves were plotted. We know that FRP does not fatigue when stressed to no more than 1/2 of its ultimate strength. It does not yield as do other materials such as steel. Ultimate strength and yield strength are the same. It would be extremely unlikely that FRP rebar would be designed to working load of more than 1/4 of Ultimate Strength (approximately 160,000 psi) What is the Ultimate Strength for the different sizes of Rebar? “Ultimate Strength” refers to per unit values. It is a physical property of the material itself that applies to all sizes and shapes into which the material may be formed. Tests indicate that the Ultimate Strength of the FRP rebar is approximately 160,000 psi maximum. The “breaking strength” of various sizes of rebar can vary in inverse relation to bar size – from 160,000 psi for smaller sizes, to 100,000 psi for larger bars. How do you use FRP rebar in beam and slab
