PSI - Issue 28

Haya H. Mhanna et al. / Procedia Structural Integrity 28 (2020) 811–819 Mhanna et al. / Structural Integrity Procedia 00 (2020) 000–000

813

3

2. Research significance and objectives Shear failure in RC beams is sudden and brittle with no warning signs exhibited prior to failure. As a result, it is vital to strengthen shear deficient RC beams to avoid catastrophic failures. Strengthening using FRP materials has proven to be effective in enhancing shear capacity, but the system is limited by early debonding of the FRP laminates prior to utilizing the laminate’s tensile strength. One approach to delay or prevent debonding is to anchor the FRP laminates. Of all anchorage systems studied, FRP splay anchors demonstrated the capability to develop the laminate’s tensile capacity when used in flexural and shear applications. Thus far, many studies investigated the pullout capacity of isolated FRP anchors. However, very few studies investigated shear strengthening of full-scale RC beams with FRP laminates, anchored with FRP-splay anchors. In addition, the strengthening design codes of practice lack guidelines to design the anchors. Therefore, the main objective of this study is to investigate the effect of strengthening RC T beams with U-wrapped carbon-FRP (CFRP) laminates that are anchored with CFRP splay anchors. The varying anchor parameter in this study is the dowel diameter. 3. Experimental program 3.1. Test specimens In this study, a total of five shear deficient reinforced concrete T-beams were tested to failure. The overall depth of the beams is 350 mm and the effective depth is 309 mm. The beams have a total length of 2.0 m and a shear span-to depth ratio of 2.75. To ensure shear failure, the beams were reinforced with four longitudinal tension bars of 16 mm and two longitudinal compression bars of 12 mm. In addition, to force shear failure in one shear span, the beams were reinforced with 10 mm steel stirrups spaced at 100 mm in the other unstrengthened shear span. The reinforcement details and geometrical dimensions of the specimens are shown in Fig. 1.

Fig. 1. Specimen geometry and reinforcement details.

3.2. Test matrix To achieve the objectives of this study, the experimental program consists of five RC beam specimens. One specimen was left unstrengthened (C) to serve as a control specimen. Four specimens were strengthened with CFRP U-wraps spaced at 100 mm center-to-center, one of which was left unanchored (BSU) and the remaining three were