FIBER COMPOSITE PLATES CAN STRENGTHEN BEAMS

It is described how epoxy-bonded glass fiber-reinforced plastic plates can provide a corrosion-free solution to increasing the load-carrying capacities of concrete bridges. The addition of epoxy-bonded steel plates to the tension face of concrete girders has been used effectively in Europe and elsewhere to repair and strengthen reinforced concrete elements with insufficient load carrying capacity due to mechanical damages, functional changes, or corrosion. The advantages of the method include ease of application and elimination of the special anchorages needed in the post-tensioning method; a shortcoming is the danger of corrosion at the epoxy-steel interface which adversely affects the bond strength. This problem may be eliminated by replacing steel plates with corrosion-resistant synthetic materials such as fiber composites. Studies in this field are described. Other applications of epoxy bonded steel plates to concrete girders are described. A program to test the static strength of concrete beams strengthened with epoxy bonded glass fiber reinforced plastic plates is also described.