In bridge inspections, what does "fatigue failure" refer to?

Fatigue failure refers to the gradual weakening of materials as a result of repeated loading cycles over time. This phenomenon occurs when structural components are subjected to fluctuating stresses, which can lead to the development of small cracks that grow progressively larger with each load cycle. Eventually, if the stress is sustained and the cracks propagate sufficiently, a complete failure can occur without any prior warning.

This is particularly significant in bridge inspections since many bridges experience dynamic loads such as traffic and environmental factors that can contribute to these fatigue effects. Understanding fatigue failure is crucial for inspectors to identify signs of distress and to implement maintenance strategies that can prolong the life of the bridge and ensure safety. While other failures might involve sudden collapses or environmental factors, fatigue failure distinctly emphasizes the prolonged effects of stress repetition and material fatigue.