Structural Reliability Assessment of Post-Weld Treatment Methods for Fatigue Life Extension of Aging Steel Bridges

Abstract

The management of aging steel bridges poses significant challenges to bridge owners, who must maintain structural integrity under fatigue-induced deterioration while operating within limited maintenance budgets. Although post-weld treatment methods have demonstrated potential to improve fatigue performance, a probabilistic quantification of their comparative reliability benefits remain limited in literature. This study presents a probabilistic S-N based reliability approach to evaluate and compare as-welded condition and three post-weld treatment methods, including burr grinding/TIG, needle/hammer peening, and HFMI. The approach is applied to a welded steel detail under variable amplitude loading, incorporating uncertainties in the fatigue resistance, damage accumulation and stress modelling. The results show that post-weld treatments significantly extend service life. Furthermore, an analysis shows the potential of SHM also contributing to service life extension, however, subjected to a specific outcome probabilities