Bond Shear Tests to Evaluate Different CFRP Shear Strengthening Strategies for I-Shaped Concrete Cross-Sections

• Published in: Materials Vol. 17; no. 13; p. 3342
• Main Authors: Yaqub, Muhammad Arslan, Czaderski, Christoph, Matthys, Stijn
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 05.07.2024
• Subjects: Aerated concrete; Aeration; Anchor bolts; Anchorages; Bonding strength; Carbon fiber reinforced concretes; Carbon fiber reinforced plastics; carbon fibre reinforced polymers (CFRP); Concrete blocks; Configurations; Cross-sections; debonding; Design; Fiber reinforced polymers; Girder bridges; Girders; I-shaped concrete cross-sections; in-fill blocks; Precast concrete; Prestressed concrete; Reinforcing steels; Shear strength; shear strengthening; Shear tests; Steel plates; Strengthening; Stress concentration; Canada; in-fill blocks; I-shaped concrete cross-sections; shear strengthening; carbon fibre reinforced polymers (CFRP); debonding; anchorages
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma17133342

I-shaped concrete girders are widely used in precast bridge and roof construction, making them a common structural component in existing infrastructure. Despite well-established strengthening techniques using various innovative materials, such as externally bonded carbon fibre reinforced polymer (CFRP) reinforcement, the shear strengthening of an I-shaped concrete girder is not straightforward. Several research studies have shown that externally bonded CFRP reinforcement might exhibit early debonding at the concave corners of the I-shape, resulting in a marginal increase in shear capacity. This research study aims to assess the performance of two different CFRP shear strengthening strategies for I-shaped concrete cross-sections. In the first strategy, CFRP was bonded along the I-shape of the cross-section with the provision of additional anchorage. In the second strategy, the I-shape was transformed into a rectangular shape by using in-fill blocks over which the CFRP was bonded in a U-configuration. In addition to the strengthening strategies, the investigated parameters included two different materials for the in-fill blocks (conventional and aerated concrete) and two different anchoring schemes (bolted steel plate anchor and CFRP spike anchor). To avoid testing on large-scale girders, a new test methodology has been implemented on concrete I-sections. The test results demonstrate the feasibility of comparing different shear strengthening configurations dedicated to I-sections. Among other findings, the results showed that the local transformation of the I-shape to an equivalent rectangular shape could be a viable solution, resulting in shear strength enhancement of 12% to 53% without and with the anchorages, respectively.