Fatigue performance of old bridge steel and the procedures for life prediction with given survivability

• Published in: Engineering fracture mechanics Vol. 53; no. 2; pp. 251 - 262
• Main Authors: Zheng, Xiulin, Li, Zhen, Shi, Yongji, Yang, Yanman, Shi, Zhijiang
• Format: Journal Article
• Language: English
• Published: Tarrytown, NY Elsevier Ltd 1996; Oxford Elsevier
• Subjects: Applied sciences; Buildings. Public works; Exact sciences and technology; Fatigue; Fracture mechanics (crack, fatigue, damage...); Fracture mechanics, fatigue and cracks; Fundamental areas of phenomenology (including applications); Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; Physics; Solid mechanics; Strength of materials (elasticity, plasticity, buckling, etc.); Structural analysis. Stresses; Structural and continuum mechanics; Bridges; Fatigue life; Crack formation; Fatigue test; Measuring methods; Structural steel; Damage; Experimental study; Lognormal distribution; Fatigue crack
• ISSN: 0013-7944; 1873-7315
• DOI: 10.1016/0013-7944(95)00076-3

In the present study, the fatigue life of the steel of an old bridge on the line from Beijing to Shenyang, which was constructed in 1920s and replaced in 1980s, has been experimentally determined by using specimens with the original rivet central holes and the key-hole CT specimens without the damaged surface layer. Procedures are developed to predict the fatigue life of the specimens of the steel of an old bridge under two levels loading. Test results show that the fatigue life determined at the same equivalent stress amplitude follows the usual log-normal distribution, and can be better expressed as a function of the equivalent stress amplitude, which shows the existence of the fatigue threshold. Furthermore, the expressions of the fatigue life for a given survivability are presented. Using these expressions and the procedures proposed in the present study, one can predict the fatigue life of the specimens of old bridge steel under variable amplitude loading. The predicted results show that the fatigue life of old bridge steel specimens follows the log-normal distribution under two-level loading, which is substantiated. Test results and analysis also show that the fatigue performance of the old bridge steel was degenerated due to the surface damage in its long-term operation.