Fatigue Performance of High‐Strength Bolted Joints Affected by Pre‐loading Decrease

Abstract Structural integrity of existing steel and composite bridges strongly depends on the performance of details adopted for connections. When assessing the vulnerability of viaducts featuring high‐strength bolted joints, a key issue is often represented by fatigue performance of connections, i.e., due to the detrimental influence of several factors including progressive pre‐tightening reduction during service life. Within such framework, this study presents a parametric analysis of the effect of pre‐tightening loss on the fatigue response of high‐strength bolted joints. For this purpose, a refined numerical application of the Strain Energy Density (SED) method is developed with reference to different geometrical configurations. Discovered findings indicate that pre‐tightening reduction can severely impair the fatigue life of these details, i.e., reducing the expected number of cycles at failure by up to one order of magnitude in worst cases.