Externally Bonded And Near-Surface Mounted FRP Strips For Shear Strengthening Of RC Deep Beams

Abstract

This thesis presents an experimental study on the efficacy of fiber reinforced polymer (FRP) strips using externally bonded (EB) and near surface mounted (NSM) techniques for the shear strengthening of reinforced concrete (RC) rectangular deep beams. The experimental program included construction and testing of nineteen medium-scaled RC rectangular deep beams. Five beams were kept unstrengthened to act as references, while seven beams were strengthened using the EB technique, and the remaining seven beams were strengthened using the NSM technique. All beams have been tested under three-point loading with a displacement rate of 0.25 mm/min. A typical critical shear span to effective depth ratio (a/d =1.6) was fixed for all beams. The interaction between the shear stirrups and the strengthening systems has been investigated. The test variables included the FRP configurations (two, three, and four EB/NSM-FRP), steel stirrups at the CSS configurations (two, three, and nil), and the relation between steel stirrups and the strengthening system at the CSS (aligned and unaligned). The test results revealed that both EB and NSM techniques could be used to enhance the shear capacity and deformational characteristics of RC rectangular deep beams. The NSM technique has shown better performance with an average increase in the ultimate load capacity of 41.4%, while that was 10.1% for the EB technique.