Fatigue Life Prediction and Variability of New and Existing Welded CHS Y-Joints

An experimental program was undertaken to quantify fatigue life variability of the ET fatigue detail category for welded circular hollow shape (CHS) connections commonly found in sign support structures. The program included fatigue testing of existing and fabricated Y-joint specimens composed of CHS, detailed material characterization, and comparison of experimentally determined fatigue lives with a variety of analytical methodologies. The results of the research effort serve as the foundation for quantifying the expected service life for overhead sign support structures in relation to the fatigue limit state of the welded connections. The data has been used as the basis for a procedure for predicting the service lives of full-span overhead sign support trusses.