Flexural Performance and Failure Modes of NSM CFRP-Strengthened Concrete Beams: A Parametric Study

Performances, challenges and opportunities in strengthening reinforced concrete structures by using FRPs – A state-of-the-art review

“…Haddad and Almomani [58] found a 154% increase in the flexural strength and 85% improved rotational ductility by using a FRP NSM strip in a RC beam. The concrete cover and embedment length are important in a NSM strengthening system [58,59]. The wrapping of a column with an EB-FRP sheet may have little impact in improving the flexural performance during bending, but the NSM strip technique of strengthening has been proven to be effective [44].…”

“…Strengthening of RC slabs by using FRP strips was found to be very effective and may improve the strength by around 40-90% when the fibres of the FRP are oriented at zero degrees and bonded along the maximum bending zone [8,57]. Haddad and Almomani [58] found a 154% increase in the flexural strength and 85% improved rotational ductility by using a FRP NSM strip in a RC beam. The concrete cover and embedment length are important in a NSM strengthening system [58,59].…”

“…propagates towards the ends [57,58,78]; it also originates from the ends of flexural-or shear-induced cracks, where a large moment to shear ratio is observed, and propagates towards the low-moment regions [128].…”

“…A structures cannot realise its ultimate strength and the full tensile strength of a FRP cannot be utilised when debonding failure initiates [5,33], which is brittle failure. This debonding can be delayed by using intermediate anchorage of FRP laminates to reduce the interfacial stresses [50,126,129,130], or through a high embedment length of a NSM strip [58], but their effectiveness should be justified appropriately [45].…”

Experimental and analytical investigation on flexural behaviour of RC beams strengthened with NSM CFRP prestressed concrete prisms

“…At present, the CFRP strengthening technique for RC structural members includes the externally bonded (EB) strengthening technique and the near-surface mounted (NSM) technique. The NSM CFRP technique has become an effective method for strengthening RC beams, which can significantly improve the flexural performance and stiffness compared with the EB strengthening technique [6,8,13,14]. Additionally, it shows better durability, fatigue resistance and bonding performance in comparison with the EB CFRP strengthening technique [15,16].…”