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This paper discusses the flexural strengthening of continuously reinforced concrete (RC) beam constructions in hogging or sagging regions using near-surface mounted (NSM) technique. The main difficulties in strengthening RC continuous beams in hogging are the vertical middle column which prevents continuity of the NSM reinforcement bars and end anchorage of the NSM reinforcement. A test program consisted of seven two-span Tbeams was used; one control beam, which was used for comparison, four beams were strengthened at the hogging region, and two beams were strengthened at the sagging regions. Two types of strengthening material were adopted in this study, carbon fiber reinforced polymers (CFRP) rebars, and high tensile steel bars. An RC column loaded with a constant load (120 kN) was used as the middle support. The main test parameters were the type of the reinforcement bars, continuous NSM bars beside the middle column, or NSM bars anchored inside the middle column, as well as the strengthened region. Besides, the impact of using embedded through-section (ETS) end anchorage of NSM CFRP bars was investigated as well. The experimental results were evaluated for the effects of strengthening technique and materials on the load-carrying capacity of beams, deformation, ductility index, and moment redistribution. The experimental results showed that strengthening with NSM steel bars could improve the service load carrying capacity by 23–40%, whereas the NSM CFRP rebars improved the service loads by 33–36%. The ETS end anchorage at the hogging region and the NSM steel bars at the sagging region helped to achieve the flexural rigidity by a very significant amount relative to the other strengthened beams and control beam by 270%. The moment redistribution achieved after the beam cracking load until the failure load varies in accordance with the strengthening region and the strengthening material type.

This paper discusses the flexural strengthening of continuously reinforced concrete (RC) beam constructions in hogging or sagging regions using near-surface mounted (NSM) technique. The main difficulties in strengthening RC continuous beams in hogging are the vertical middle column which prevents continuity of the NSM reinforcement bars and end anchorage of the NSM reinforcement. A test program consisted of seven two-span Tbeams was used; one control beam, which was used for comparison, four beams were strengthened at the hogging region, and two beams were strengthened at the sagging regions. Two types of strengthening material were adopted in this study, carbon fiber reinforced polymers (CFRP) rebars, and high tensile steel bars. An RC column loaded with a constant load (120 kN) was used as the middle support. The main test parameters were the type of the reinforcement bars, continuous NSM bars beside the middle column, or NSM bars anchored inside the middle column, as well as the strengthened region. Besides, the impact of using embedded through-section (ETS) end anchorage of NSM CFRP bars was investigated as well. The experimental results were evaluated for the effects of strengthening technique and materials on the load-carrying capacity of beams, deformation, ductility index, and moment redistribution. The experimental results showed that strengthening with NSM steel bars could improve the service load carrying capacity by 23–40%, whereas the NSM CFRP rebars improved the service loads by 33–36%. The ETS end anchorage at the hogging region and the NSM steel bars at the sagging region helped to achieve the flexural rigidity by a very significant amount relative to the other strengthened beams and control beam by 270%. The moment redistribution achieved after the beam cracking load until the failure load varies in accordance with the strengthening region and the strengthening material type.

This paper discusses the flexural strengthening of continuously reinforced concrete (RC) beam constructions in hogging or sagging regions using near-surface mounted (NSM) technique. The main difficulties in strengthening RC continuous beams in hogging are the vertical middle column which prevents continuity of the NSM reinforcement bars and end anchorage of the NSM reinforcement. A test program consisted of seven two-span Tbeams was used; one control beam, which was used for comparison, four beams were strengthened at the hogging region, and two beams were strengthened at the sagging regions. Two types of strengthening material were adopted in this study, carbon fiber reinforced polymers (CFRP) rebars, and high tensile steel bars. An RC column loaded with a constant load (120 kN) was used as the middle support. The main test parameters were the type of the reinforcement bars, continuous NSM bars beside the middle column, or NSM bars anchored inside the middle column, as well as the strengthened region. Besides, the impact of using embedded through-section (ETS) end anchorage of NSM CFRP bars was investigated as well. The experimental results were evaluated for the effects of strengthening technique and materials on the load-carrying capacity of beams, deformation, ductility index, and moment redistribution. The experimental results showed that strengthening with NSM steel bars could improve the service load carrying capacity by 23–40%, whereas the NSM CFRP rebars improved the service loads by 33–36%. The ETS end anchorage at the hogging region and the NSM steel bars at the sagging region helped to achieve the flexural rigidity by a very significant amount relative to the other strengthened beams and control beam by 270%. The moment redistribution achieved after the beam cracking load until the failure load varies in accordance with the strengthening region and the strengthening material type.

This paper investigates experimentally the relation between tensile reinforcement of sagging and hogging region on the performance of the reinforced concrete continuous T-beams and their effect on the moment redistribution. Four two-span RC continuous beams were manufactured and tested up to failure, three of them were designed with a loaded central concrete column. This research provides an insightful and comprehensive description of the carrying capacity, deformation, ductility index, and moment redistribution of the continuous beam with the different steel reinforcement ratio at critical zones. The results show that the load-carrying capacity of continuous beams depends mainly on the longitudinal reinforcement at sagging region rather than that of the hogging region. The sagging reinforcement improves the ductility and the serviceability of the continuous beams at the allowable deflection and the permissible crack width. The moment redistribution ratio depends on the ratio between the sagging reinforcement and the hogging reinforcement areas, especially after the yielding loads. At the hogging and sagging regions with equal reinforcement areas, the moment redistribution values were reduced in comparison to the other tested beams.