Preventing Debonding of Externally-bonded Steel Plates from Concrete Substrate through Surface Nanocrystallization

IP Title

Preventing Debonding of Externally-bonded Steel Plates from Concrete Substrate through Surface Nanocrystallization

Summary

Three inventions are introduced. The first one, HB-FRP, addresses the critical debonding problem in externally-bonded FRP for rehabilitation of reinforced concrete (RC) structures. By using special but simple mechanical fasteners, the researcher can solve the critical intermediate crack induced debonding problem through the mechanism of frictional bond.

The second invention overcomes debonding problem by using nanostructured steel plates for strengthening RC structures. Surface nanocrystallization using SMAT technology can largely increase yield strength of thin steel plates. By increasing tensile strength in certain parts of the plate, tensile straining and yielding are diverted and localized to relatively weaker portions. As debonding is closely related to tensile strain of the externally bonded reinforcement, nano-treated areas that have a much smaller strain than untreated areas can block the spreading of debonding to other areas. As a result, global detachment of external reinforcement can be avoided.

The third technology is provision of ductility to flexural members through compressive yielding (CY), instead of conventional tensile yielding of reinforcement bars. The CY beams rely on the compressive deformation of plastic hinges to achieve ductility. In this way, adequate ductility of the RC members can be achieved without ductility demand on non-ductile tensile reinforcement such as FRP bars.

Technology Benefits

Overcoming critical technical problems in application of advanced materials with relatively low cost and labor

Technology Application

Construction industry, especially for bridge and infrastructural engineering

Application Date

01/01/2011

ID No.

13/176,305

Country/Region

Hong Kong

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