Development of a New Construction Technology/Product for Structural Rehabilitation with FRP

Description

The externally bonded fiber-reinforced polymer (EB-FRP) is currently one of the most popular methods for rehabilitation (strengthening/repairing/retrofitting) of concrete structures. However, the efficacy of this method is limited by the relatively weak adhesive interface, which often causes the premature debonding failure of the FRP materials from the concrete substrate. This problem can be effectively overcome by hybrid bonded FRP system (HB-FRP) - a new technology developed by the PI, in which small mechanical fasteners are used to augment the bond. Through five years of extensive investigations on the HB-FRP technology, its effectiveness in enhancing bond for EB-FRP has been substantiated. Considering its high effectiveness and the lack of other solution for intermediate crack induced debonding, the proposed Hong Kong Guideline for the Strengthening of Concrete Structures Using FRP Composites makes recommendation for the use of HB-FRP for structural rehabilitation. Furthermore, a US patent has been granted in September 2010 and a Chinese patent has been filed for the new technology.However, the new technology has been developed in laboratory so far. This I2RF project aims at further developing the technology into a standard construction technology/product. The key element in the HB-FRP technology is a special mechanical fastener that is similar to a staple. A series of standardized fasteners will be developed through the proposed project. The deliverables will not only include the hardware (fasteners) but also include the software (the installation manual, design method, catalogue and computer program). Laboratory testing, numerical simulations and analytical studies will be undertaken to achieve the objectives.