Fatigue damage due to large cyclic strains is one of the main failure modes of steel structures during earthquake. This study investigated fatigue crack propagation behavior of structural steels under large cyclic strains. Crack propagation tests for plain material and deposited metal were performed with a compact tension type specimen. Besides, as an index for crack propagation, cyclic J-integral range was defined based on fracture mechanics concept and calculated by finite element analysis. Based on the results, a fatigue crack growth curve under large cyclic strains was proposed by using the cyclic J-integral range. Then, the applicability of the proposed curve was verified through fatigue tests of corner welded joints.
