Fatigue behavior of corroded steel plates strengthened with CFRP plates

Abstract

This paper presents an experimental study performed to investigate the effectiveness of carbon fiber reinforced polymer (CFRP) plates in extending fatigue life of corroded steel plates. Specimens with five kinds of corrosion damage level, four kinds of strengthening configuration and four kinds of applied fatigue stress amplitude were tested and the primary fatigue behavior indications consist of failure mode, fatigue fractography, fatigue life and crack propagation were analyzed. Results showed that externally patching CFRP plates significantly strengthened the fatigue behavior of corroded steel plates, and even made the fatigue life of corroded steel plates recovered or exceeded that of the un-corroded ones, the fatigue life of the patched specimen which presented the most significant strengthening effectiveness even showed a fatigue life extension of more than 85.3 times with respect to the un-patched corroded steel plate and approximately 2 times over the un-corroded steel plate. Results also indicated that different strengthening configurations appeared to have diversity effect on the fatigue life extension and crack growth retardation of corroded steel plates, end anchorage measures effectively delayed the failure process of CFRP bonding interface and improved the fatigue strengthening effect, increasing CFRP strengthening stiffness or adopting prestressed CFRP plates significantly reduced the crack growth rate and extended the fatigue life of corroded steel plates. The outcome of the tests provided meaningful references and essential data for the reliable application of CFRP strengthening system in the fatigue performance improvement of corroded steel structures.