Experimental Study on the Fatigue Behavior of Steel Beams Strengthened with Different Fiber-Reinforced Composite Plates

Abstract

An experimental study was conducted to investigate the fatigue behavior of artificially notched steel beams strengthened with four different types of materials tested under equivalent tensile stiffness. These materials include high-modulus carbon-fiber-reinforced polymer (HM-CFRP) plate, high-strength CFRP (HS-CFRP) plate, steel-wire basalt-fiber-reinforced polymer (SW-BFRP) plate, and welded steel plate. Some key parameters, such as material type, the number of HS-CFRP layers, the configuration of HS-CFRP, and the interface treatment of SW-BFRP, are discussed. Compared to the traditional welded steel-plate method, the test results show that the application of a fiber-reinforced composite plate can not only delay crack initiation, decrease the crack growth rate, and prolong the fatigue life, but also reduce the stiffness decay and residual deflection. HM-CFRP exhibited the best strengthening performance; however, SW-BFRP is the optimal strengthening material on the basis of the cost–performance ratio. The fatigue behavior of steel beams can be improved significantly by increasing the layers of strengthening material. SW-BFRP with a rough surface can prolong the fatigue life of steel beams more effectively than SW-BFRP with a smooth surface. The plate configuration has certain effects on the fatigue life.