DESIGN OVERVIEW FOR RC MEMBERS STRENGTHENED USING NEAR SURFACE MOUNTED FRP COMPOSITES

The use of Near Surface Mounted FRP reinforcement for increasing flexural and shear strength of deficient reinforced and pre-stressed (RC and PC) members (Alkhrdaji et al. 1999, De Lorenzis et al. 2000) as well as strengthening unreinforced masonry walls (Tumialan et al. 2001) has gained popularity in recent decades. The various advantages compared to externally bonded FRP laminates include but not limited to the possibility of anchoring reinforcement into adjacent members, upgrading elements in their negative moment region with reinforcement not exposed to potential mechanical damage typical to floor or deck systems (Nanni et al. 1999). NSM FRP technique minimises surface preparation work. Since the use of primer and putty is not necessary the installation time after groove cutting is also minimised when compared to externally bonded FRP laminates. NSM reinforcement also finds application in seismic retrofitting of RC column-beam joints to either provide additional strength or ductility when moving the failure zone from column to beam (Prota et al. 2001). The aesthetics of the strengthened structure is virtually unchanged. Because of these advantages NSM FRP method is in many cases superior to externally bonded FRP method or used in combination with it. Researchers across the globe have become aware of the practical advantages of this method resulting in boom in research in this area. Against this background this paper provides a comprehensive review of existing research in this area, gaps in knowledge and outlines for further future research.