42 Int. J. Sustainable Materials and Structural Systems, Vol. 1, No. 1, 2012
Copyright © 2012 Inderscience Enterprises Ltd.
Performance of NSM-FRP RC beams in flexure and
shear using locally developed CFRP rebars
S.B. Singh*, Madappa V.R. Sivasubramanian,
A. Likhith Reddy, K. Chandra Prakash,
K. Nagarjuna and A. Hima Kiran
Civil Engineering Department,
Birla Institute of Technology and Science,
Pilani, Rajasthan, 333031, India
Fax: +91-1596-244183
E-mail: sbsingh@bits-pilani.ac.in E-mail: sbsinghbits@gmail.com
E-mail: s.madappa@gmail.com
E-mail: likhithreddy@gmail.com
E-mail: chandraprakash.khatri@gmail.com
E-mail: alphat.prince@gmail.com
E-mail: himakiranalladi@gmail.com
*Corresponding author
Abstract: In the present study, an experimental investigation was carried out to
evaluate the flexural and shear capacity of near surface mounted (NSM)
reinforced concrete (RC) beams using carbon fibre reinforced polymer (CFRP)
rebars. A total of 16 half scale beams were tested to study the flexural and shear
responses of strengthened RC beams. The CFRP rebars were manufactured at
structural testing centre using locally developed twisting equipment to
strengthen the RC beams. Also, new anchor system was locally developed to
predict the tensile characteristics of CFRP bars using universal testing machine.
To examine the flexural and shear behaviour, all beams were tested under
two-point loading system. It was observed that the NSM strengthened RC
beams have higher load carrying capacity than the corresponding control beam
in flexure and shear by 68% and 35.6%, respectively. Typical failure modes of
the beams during the experimental investigation were CFRP rupture, CFRP
debonding, crushing of concrete and shear failure. Finally, a design example
has been presented for better understanding in the analysis and design of NSM
FRP strengthened RC beams. Further, the values obtained from the analytical
study are in good agreement with the experimental values.
Keywords: beam; composite; design example; flexure; NSM-FRP;
performance; strengthening; shear; sustainable materials.
Reference to this paper should be made as follows: Singh, S.B.,
Sivasubramanian, M.V.R., Likhith Reddy, A., Chandra Prakash, K.,
Nagarjuna, K. and Hima Kiran, A. (2012) ‘Performance of NSM-FRP RC
beams in flexure and shear using locally developed CFRP rebars’, Int. J.
Sustainable Materials and Structural Systems, Vol. 1, No. 1, pp.42–67.
Biographical notes: S.B. Singh is an Associate Professor and the Head of
Civil Engineering Department, BITS-Pilani, India. He is also a registered
Professional Engineer (PE) in the state of Michigan, USA. His major areas of
research interest are finite element analysis and composite structures. His
interest also includes strengthening of concrete structures using FRP materials.