Not all loads contribute to fatigue crack propagation in the welded detail of steel bridges when they are subjected to variable amplitude loading. For fatigue assessment, therefore, non-contributing stress cycles should be truncated. However, stress range truncation is not considered during typical fatigue reliability assessment. When applying the first order reliability method, stress range truncation occurs mismatch between the expected number of cycles to failure and the number of cycles obtained at the time of evaluation, because the expected number of cycles only counts the stress cycles that contribute to fatigue crack growth. Herein, we introduce a calibration factor to coordinate the expected number of cycles to failure to the equivalent value which includes both contributing and non-contributing stress cycles. The effectiveness of stress range truncation and the proposed calibration factor was validated via case studies.
Fatigue reliability assessment Linear elastic fracture mechanics Steel bridge Fatigue Fatigue limit state
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This research was partially supported by a Grant (17SCIP-B128568 2) and a Grant (18SCIP-B119963-03). Both Grants were funded by the Ministry of Land, Infrastructure and Transportation of the Korean government. Partial support was from the BK21 PLUS research program of the National Research Foundation of Korea.
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