Recycled CFRP Plate Retrofitting using Adhesive and TRS for Steel Girders

The retrofitting method using CFRP (Carbon Fiber Reinforced Plastic) plates was applied to a steel highway bridge in 2002 for the first time in Japan, where some of CFRP plates have been detected to be peeled from their ends, recently. CFRP plates are light‐weight and anti‐corrosive comparing with steel plates, while they have problems in the durability of adhesives bonding CFRP plates to steel plates. Currently, recycled CFRP plates have been developed for the environmental load reducing. Additionally, long sized CFRP plates are required to retrofit bridge members. In this study, the effectiveness of TRS (Thread Rolling Screw) used to connect the long‐size recycled CFRP plate end to the steel girder bottom flange with adhesives is investigated through static and fatigue loading tests using large size steel girder specimens. As a result, TRS can prevent long‐size recycled CFRP plates from peeling off under allowable stress static loadings, while the long‐size recycled CFRP plates connected by only adhesives without TRS peeled off from their ends. In fatigue loading tests, TRS can also prevent long‐size recycled CFRP plates from peeling, though fatigue cracks were developed from TRS holes under higher stress range.