Fatigue, deterioration and system analysis of the Boyne Viaduct

Abstract

The iconic Boyne Viaduct located in Drogheda, Ireland, is currently beyond its intended design life and it is now vital that the structure be appropriately assessed to ensure ongoing safety in practice. In this paper, a reliability analysis of the central span of the steel superstructure is used to optimise a Structural Health Monitoring strategy. The data is used to calibrate an FE model and update the uncertainty in the reliability analysis. Structural dynamics were considered by way of probabilistic dynamic amplification of live load effects. Probabilistic models for steel pitting corrosion are employed to investigate the effect on the structural reliability. An overall reliability index is calculated for the structure based on a system analysis. Finally, a measurement-based probabilistic fatigue assessment of one of element is compared to a model-based assessment, with consideration of loading history. Although the reliability was very high at the Fatigue Limit State, the results show that consideration of the loading history resulted in an increase in the failure probability, due to the past presence of freight loading on the structure.