North American design guidelines for concrete reinforcement and 4 strengthening using FRP : principles , applications and unresolved issues

21 Abstract 22 23 This paper reports on the North American state-of-the-art in the use of FRP composites in concrete structures. For new 24 construction, FRP bars have been used as the internal reinforcement in concrete members to replace conventional steel rebars for 25 a host of reasons. The principles for design and construction have been established and proposed to industry by the American 26 Concrete Institute (ACI). For repair and upgrade, strengthening of concrete members with externally bonded FRP laminates or 27 near surface mounted (NSM) bars has received remarkable attention. The design and construction principles for use in practice 28 are being finalized by ACI. On the application side, FRP materials have been used in some multi-million dollar projects for 29 strengthening parking garages, multi-purpose convention centers, office buildings and silos. The drivers for this technology are 30 several, but perhaps the most relevant one is the ease of installation. In the repairyupgrade arena (as well as new construction), 31 perhaps one of the most important unresolved question remains that of durability (including fire resistance). Further research and 32 validation is necessary to increase confidence in FRP technology for concrete construction. 33 2003 Published by Elsevier Science Ltd. 34 35