Bilinear S-N Curves and Equivalent Stress Ranges for Fatigue Life Estimation

Abstract

With the magnitude of some stress cycles in a live load stress range spectrum being higher than the constant amplitude fatigue limit (CAFL) of a structural detail, the development of a fatigue crack could be expected. The current procedure in the AASHTO specifications for fatigue life estimation utilizes an equivalent constant amplitude stress range with the direct extension of the