Design of Reinforced Concrete for Fatigue

An extensive experimental investigation to determine the fatigue strength of deformed reinforcing bars was recently completed by the Portland Cement Association. This work was sponsored in part by the National Cooperative Highway Research Program (NCHRP). The experimental program was carried out with each test bar embedded as the main reinforcing element within a concrete beam. Test variables included size of beam, size of bar, grade of bar, bar deformation geometry, minimum stress, and stress range. A total of 353 tests were carried out. This paper describes the test program and the design provisions developed by statistical procedures from the test data. An example of the application of the provision in bridge design is presented in an appendix.