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

Abstract

© 2020 Elsevier Ltd This investigation aims to study the flexural behaviour of reinforced concrete (RC) beams strengthened with near-surface mounted (NSM) carbon fibre reinforced polymer prestressed concrete prisms (CFRP-PCPs). Eight RC beams were tested under monotonic loading until the failure load was reached. One beam was un-strengthened to act as a control beam. The other seven beams were strengthened with non-prestressed or prestressed NSM CFRP-PCPs. The effects of bond length, prestress level, and concrete type of the CFRP-PCPs on the flexural capacity, flexural crack and deflection are discussed in this paper. The results indicate that the flexural capacity of RC beams strengthened with NSM CFRP-PCPs was greater than the control beam. An obvious improvement was discovered in the crack resistance when the RC beams were strengthened with prestressed NSM CFRP-PCPs. The strengthened beams showed a higher first-cracking, yielding, and ultimate load as the bond length and prestress level of CFRP-PCPs increased up to a critical level. The beams strengthened with CFRP-PCPs, which were cast with ultra-high performance concrete (UHPC), exhibited greater load capacity than the corresponding beams with epoxy resin mortar. The analytical model of flexural response for the NSM CFRP-PCPs strengthening beams is presented. The analytical results are in good agreement with the experimental results, which revealed the NSM CFRP-PCPs is an effective technique for flexural strengthening of the RC beams.