Service life under the influence of imperfect installation conditions: a probabilistic fatigue framework for bolted railway noise barrier connections

Adopting a probabilistic framework, this study quantifies train-induced aerodynamically fatigue loading in bolted connections between noise-barrier steel posts and concrete edge beams on high-speed railway bridges. Train passages generate a sinusoidal pressure and suction shock load that causes cyclic loading and preload losses of the bolted connections. Defective installation conditions – primarily inclined bolts and insufficient bolt preload – locally increase fatigue stress and connection uncertainties, thereby shortening the structural service life. The paper presents an assessment methodology that enables the integration of structural health monitoring data. The proposed framework combines probabilistic fatigue modelling with parameters calibrated through numerical simulations and experimental investigations, explicitly accounting for deviations from ideal installation conditions. The database comprises laboratory measurements on preload evolution, bolt misalignment, and load-induced response quantities within the bolted connection. The probabilistic fatigue analyses are expressed in terms of reliability indices aligned with consequence classes, allowing for condition-based maintenance planning and resource-efficient strengthening measures. By enabling the integration of monitoring data into a probabilistic fatigue framework calibrated by experiments and simulations, the study provides a scalable, reliability-based methodology applicable to both existing and newly constructed noise barriers on high-speed railway lines.