Applicability of the ASTM compliance offset method to determine crack closure levels for structural steel

The usefulness of the compliance offset method recommended by the ASTM standard to estimate crack closure in structural steel is examined. The local and remote compliance data generated in fatigue tests on a structural steel conducted under a variety of loading conditions enabled to choose an optimal strain gauge positioning and most appropriate offset criterion values for the original compliance offset method and for its modified (normalized) version. The quality of the closure measurements is assessed through checking the ability of the resulting effective stress intensity factors to account for the observed effects of the loading conditions on the fatigue crack growth rates.