Fiber-Reinforced Polymer Strengthening of Steel Beams under Static and Fatigue Loadings

Abstract

In this paper, nonlinear finite element analysis (FEA) was used to investigate the behavior of fiber-reinforced polymer (FRP) retrofitted steel beams subjected to static and fatigue loadings. Under static loading, damaged and undamaged steel beams were retrofitted with carbon FRP (CFRP) to examine the effect of bond length and transverse anchorages on flexural behavior and failure modes. Under fatigue loading, damaged control, basalt FRP (BFRP), and aramid FRP (AFRP) retrofitted steel beams were analyzed to predict their fatigue life. The CFRP laminates provided an increase in the flexural capacity for the undamaged and damaged beams by approximately 1.7 and 3 times, respectively, as compared to their counterpart control beams. The effective FRP laminate bond length under static loading condition was found to be 2/5 of the simply supported beam length. Furthermore, with the addition of anchorages, the flexural capacity was increased by 1.5 times under fatigue loading, a regression analysis was performed to generate new S-N curves, and formulas were proposed to predict the fatigue life of BFRP and AFRP strengthened steel beams.