A criterion for fatigue failure mode evaluation of U-rib to deck joints

In this study, a numerical analysis model was established, on basis of the traction structural stress method, for fatigue failure mode prediction of orthotropic bridge deck (OBD) under symmetric three-point bending conditions. The structural stress-based criterion was validated by comparison with a collection of 64 test results. Fatigue failure modes are found to hinge on a dimensionless normalized constraint distance l/lcr that is related to specimen geometric dimensions and supporting arrangements. OBD specimens in symmetric three-point bending fatigue tests fail at toe-U-rib and external toe-deck as the actual constraint distance l is lower and higher than the critical constraint distance lcr where fatigue failure mode changed. The prediction power of the evaluation criterion is not affected by the fatigue load patch width in fatigue tests, U-rib profile shape, or weld penetrations.