Experimental Investigation of Reinforced Concrete T-Beams Strengthened in Shear with Externally Bonded CFRP Sheets

Abstract

An experimental investigation was undertaken into the effectiveness of unanchored and anchored externally bonded (EB) U-wrapped carbon fibre reinforced polymer (CFRP) shear strengthening for reinforced concrete T-beams at a range of realistic sizes. The T-beam sizes, geometry and reinforcement were chosen to reflect existing slab-on-beam structures with low levels of transverse steel shear reinforcement. Geometrically similar reinforced concrete Tbeams were tested across three sizes ranging from 360 to 720 mm in depth and with different amounts of EB CFRP shear reinforcement. The beams were subjected to three-point bending with a span to depth ratio of 3.5. All the beams failed in diagonal shear. The experimental results indicate significant variability in the capacity of unstrengthened control beams, and a number of these control beams showed greater shear capacity than their EB CFRP strengthened counterparts. Greater thicknesses of CFRP reinforcement did not lead to increased shear capacity compared with lesser thicknesses of unanchored or anchored EB CFRP, but anchored EB CFRP did lead to moderate increases in shear capacity compared to both control and unanchored EB CFRP strengthened beams.

Cracking Behavior of RC Beams Strengthened with Different Amounts and Layouts of CFRP

“…A new bond strength model was proposed using a test database to predict the strengthening performance of the FRCM composite. Foster et al did an experimental investigation on reinforced concrete T-beams of varied sizes to determine the effectiveness of unanchored and anchored externally bonded U-wrapped CFRP [30]. Beams were subjected to three-point bending with a span to depth ratio of 3.5.…”

“…Several researchers compared the experimental and analytical flexural and shear capacities of different CFRP strengthened RC beams [21][22][23][24][25][26][27][28][29][30][31][32]37,38]. However, most of them [22,[26][27][28]37] found close analytical values when ACI 440.2R-08 [33] was used.…”

Flexure Performance of Externally Bonded CFRP Plates-Strengthened Reinforced Concrete Members

“…eir research results indicated that the load magnitude during CFRP reinforcement process is an important indicator of the ultimate strength of reinforced concrete beams, while the ultimate strength of CFRP-strengthened concrete beams is basically the same even with small initial load. Experimental and analytical investigations were also carried out on the CFRP shear and flexural strengthened concrete beams [16,17]. e experimental data indicated that greater thicknesses of CFRP did not increase the shear capacity of specimens with no unanchored method, compared with both control and unanchored CFRP-strengthened beams.…”

Arching in concrete slabs strengthened with near surface mounted fibre reinforced polymers

“…However, the use of advanced materials and innovative methods of analysis can provide engineers with an opportunity to deliver greater material efficiency and provide end users with a sustainable alternative to demolition and new construction. In recent years [7][8][9][10][11], the use of fibre reinforced polymers (FRPs) in retrofitting existing reinforced concrete structures has increased in popularity. This has typically been employed in strengthening highway bridges [12] due to the resistance of FRPs to corrosion from road de-icing salts.…”