Fatigue Enhancement of Welded Details in Steel Bridges Using CFRP Overlay Elements

Extending the fatigue life of steel bridges using fiber-reinforced polymer (FRP) composites

“…Comparisons were performed on the basis of HSS, which was shown to be an effi cient indicator of potential for fatigue damage in other studies (Hartman et al ., 2010 ;Hassel, 2011 ;Kaan et al ., 2012 ). Simulations of steel specimens repaired with CFRP overlays were performed by Gangel (2011) to investigate the effect of varying the modulus of elasticity and thicknesses of the composite overlay on the stress demand of the repaired specimens.…”

“…(b) Detail of CFRP-resin-steel bond interface. *Exaggerated scale to show detail in bond layer (Kaan et al ., 2012 calculated stress demands, which indicated that the CFRP overlay becomes less effective in increasing fatigue life as the resin layer thickness increases.…”

“…While the analyses carried out by Adams (2009) showed that the use of composite overlays had the potential to be effective in the repair of fatigue damage, experimental studies by Kaan (2008) , Kaan et al . (2012) , Alemdar et al (2009) showed that maintaining bond between the overlay and the metal is essential for this type of repair.…”

“…Another measure that could reduce the potential for debonding is the fabrication of resin pools extending beyond the edges of the CFRP overlays, which would allow a more gradual transition of stresses by staggering the geometric discontinuities induced by the edge of the overlay and the edge of the resin layer. This technique was shown to drastically increase the number of cycles prior to debonding in three point bending tests (Kaan et al ., 2012 ).…”

“…).11.26 S -N diagram of fatigue test results for test trials with a bond layer thickness of 3.2 mm ( 1 8 in )(Kaan et al ., 2012 ).…”