Fatigue diagnostic method and diagnostic system for cantilever or portal structure and amplitude measuring instrument used for the diagnosis

摘要

PROBLEM TO BE SOLVED: To easily diagnose fatigue of a cantilevered or arch-shaped structure installed under a vibration environment. SOLUTION: An amplitude measuring instrument 10 is provided in a prescribed portion 3b of a sign post 3 (structure) in an express highway. The level of a displacement amplitude in vibration of the prescribed portion 3b and the number of occurrence is measured over a fixed period by the amplitude measuring instrument 10. A level of a stress amplitude applied onto a dangerous cross- sectional part 3a of the sign post 3 for the fixed period, and the number of occurrence are calculated by a data analyzer (not shown) based on a measured result therein, so as to estimate a fatigue life of the cross-sectional part 3a.