Abstract
Reinforced concrete structures that incorporates deep beams are generally susceptible to deterioration due to weathering effects and sulphur attacks, under-design in the detailing of concrete cover and/or reinforcement, and construction errors. In lieu of demolishing and replacing these structures, rehabilitation and strengthening using carbon fiber composites becomes a cost-effective viable alternative. Recent advances in research and innovation have introduced concrete repair and strengthening systems that are primarily based on fiber reinforced polymer composites. These systems have offered engineers the opportunity to provide additional stability to the structural elements in question and to restore the damaged portions back to their original load carrying capacity. This paper investigates the effect of Carbon Fiber Reinforced Polymer (CFRP) composites in enhancing the flexural performance of damaged reinforced concrete deep beams. Two types of CFRP composites and epoxy were used in the experimental investigation carried out and as described by this paper: 1) high strength carbon fiber reinforced polymer (CFRP) plates, commercially known as MBrace Laminate, that are bonded using an epoxy resin specifically suited for the installation and used to strengthen existing structural members; and, 2) MBrace Fiber 230/4900, a 100% solids, low viscosity epoxy material that is used to encapsulate MBrace carbon, glass, and aramid fiber fabrics so that when it cures, it provides a high performance FRP sheet.Test samples were divided into four groups: A control group, and three rehabilitated test groups with CRFP fibers, where the main variable among them was the percent length of CRFP used along the bottom beam extreme surface between supports (i.e, for two of the groups reinforced with MBrace laminates), and the use of MBrace Fiber 230/4500 CRFP sheets on the 4th beam along its vertical sides as well as the bottom extreme face between supports. All beams had similar cross-sectional dimensions and reinforcement, and were designed to fail in flexure rather than shear. The results show that CFRP composites, both laminated and sheet type, have increased the load carrying capacity in comparison to the control specimen, where observations were recorded pertaining to the delayed formation of vertical flexural cracks at the section of maximum moment, and diagonal shear cracks at beam ends. The increase in the load carrying capacity varied among the three rehabilitated test group beams, with the 4th group showing the highest ultimate load carrying capacity when compared to the control specimen.
Highlights
Re inforced Concrete Deep Bea ms (RCDBs) are considered one of the most important structural ele ments in c ivil engineering practice and are widely used in different types of structures, such as tall buildings, offshore structures, foundations, bridges, transfer girders, and shear walls (A l-Sarraf et al, 2011; Attarde and Barbat, 2015; Attarde and Parbat, 2016; Kong, 2006; and Suresh and Kulkarni, 2016).Deep beams are popular for the structural horizontal elements of long spans where the number of intermediate supports are limited by architectural or navigational reasons
This paper investigates the effect of Carbon Fiber Reinfo rced Poly mer (CFRP) co mposites in enhancing the flexu ral performance of damaged rein forced concrete deep beams
The results show that carbon fiber reinforced poly mer (CFRP) co mposites, both laminated and sheet type, have increased the load carrying capacity in comparison to the control specimen, where observations were recorded pertaining to the delayed formation of vertica l fle xura l c racks at the section of ma ximu m mo ment, and diagonal shear cracks at bea m ends
Summary
Deep beams are popular for the structural horizontal elements of long spans where the number of intermediate supports are limited by architectural or navigational reasons. For deep beams built outdoors, deterioration and loss of member carrying capacity can result fro m exposure to detrimental environ mental conditions during their service life, under-design, incorrect construction practices, or even the desire to increase the load ca rrying capac ity of a perfectly sound structural system (Dav id et a l., 1998). Cracking and spalling of the concrete cover is considered one of the most primary reasons for the deterioration phenomenon, as cracking and spalling will cause loss in carrying capacity as well as allow fo r corrosion and exposure to adverse environmental conditions long term (Ahmad, et al, 2012; and Kim and Yun, 2011)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
