Experimental study on the verification of adequate fatigue test specimen size of U‐rib‐to‐deck joints in orthotropic steel bridge decks

In this study, the distribution of residual stress of the substructure model and small coupon specimens in orthotropic steel bridge structures is experimentally and numerically investigated to validate adequate specimen sizes. Blind‐hole drilling and X‐ray diffraction methods are used to capture longitudinal and transverse residual stresses and evaluate the effects of the cutting process. The maximum LRS and TRS were reduced by 16.6% and 15.6% from those that existed before cutting, verifying the proper size of small voucher specimens. The width‐to‐thickness ratio of 6–6.25 of small coupon specimens has proven sufficient to capture the effects of stress triaxiality induced by the residual stress. In the spirit of master S‐N curves in ASME standard, the role of residual stress was represented in the fatigue process and does not be additionally taken into account when predicting the fatigue performances of welded structures using prediction methods based on the S‐N curves.