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Moment redistribution and flexural performance of RC continuous T-beams strengthened with NSM FRP or steel bars

ملخص البحث
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.
مؤلف البحث
Hesham M.A. Diab, Tarek Abdelaleem⁎, Mohamed M.M. Rashwan
مجلة البحث
Structures
مؤلف البحث
صفحات البحث
1516–1538
الناشر
elsevier
تصنيف البحث
1
عدد البحث
28
موقع البحث
www.elsevier.com/locate/structures
سنة البحث
2020