Total views : 99

Deflection of Concrete Beams Prestressed by CFRP Bars


  • Kongu Engineering College, Perundurai, Erode − 638052, Tamilnadu, India


Background/Objectives: Carbon Fiber Reinforced Polymer (CFRP) is preferred due to its non-corrosive and high strength.The serviceability behavior of prestressed concrete beam changes due to the less stiffness and non-ductililty of CFRP.Methods/Statistical Analysis: An experimental investigation is carried out to study the deflection and crack width behavior of prestressed concrete beam using CFRP bars. Four rectangular beam specimens were considered forcasting, stressing by varying degree of prestressing of 35 to 70 % and tested. The moment curvature behaviors of experimental results were compared with various researchers’ recommendations. Findings: The deflection of CFRP prestressed concrete beam is by deformability of member. The deformability behavior depends on residual strain on CFRP bar after decompression of prestressing strain. The shift of moment of inertia and neutral axis of member are changing with respect to deformability behavior of member. The rate of shift of moment of inertia after first crack on member is faster for the low deformability member due to less residual strain only available in CFRP bar to deform which leads to faster rate of increase in deflection.The shift of neutral axis is due to crack on concrete leads to increase in prestressing moment of resistance. The rate of shift of neutral axis is slower for low deformability beam due to high degree of prestressing of member result in high tension stiffening at bottom of member. Reference recommendation of softening the moment of inertia by comparing modulus of elasticity of CFRP with steel is not realistic because the steel deform by ductility wherein FRP bar by deformability. Applications/Improvements: Proposed new deflection model is based on deformability behavior of CFRP prestressed concrete member, hence more number of experimental and numerical studies required validate the proposed model.


Deflection, Deformability, Moment of Inertia, Neutral Axis, Prestressing, Serviceability.

Full Text:

 |  (PDF views: 104)


  • Abdelrahman A. Serviceability of Concrete Beams Prestressed by Fibre Reinforced Plastic Tendons. PhD Thesis. University of Manitoba Winnipeg. Manitoba, 1995.
  • Dolan CW, Chad PE, Burke R. Flexural Design of Prestressed Concrete Beams Using FRP Tendons, PCI Journal. 2001; 46:76−87.
  • Burke R, Dolan CW, Hamilton III HR. FHWA Contract Final Report, University of Wyoming, Design recommendations for Concrete Structures Prestressed with FRP Tendons. 2001; 2:113−202.
  • ACI 440 4R-04. Prestressing Concrete Structures with FRP Tendons, 2011.
  • Branson DE, Trost H. Application of the I-Effective Method in Calculating Deflections of Partially Prestressed Members, PCI Journal.1982;1:62−67.
  • Tadros M, Ghali A, Meyer A. Prestress Loss and Deflection of Precast Concrete Members, PCI Journal. 1985; 30:1l4−41.
  • Toutanji HA, Saafi M. Deflection and Crack Width Predictions of Concrete Beams Reinforced with Fiber Reinforced Polymer Bars, Proceedings of Fourth International Symposium on Fiber Reinforced Polymer Reinforcement for Reinforced Concrete structures Baltimore-USA SP. 1999; 188:1−8.
  • Abdelrahman A, Rizkalla S. Deflection Control of Concrete Beams Pretensioned by CFRP Reinforcements, Journal of Composite Construction. 1999; 3:55−62.
  • Al-Sunnal Read, Kypros Pilakoutas, Peer Waldron, Tareq Al-Hadee. Deflection of FRP Reinforced Concrete Beams, Paper presented at FIP 2nd International Congress. 2006; p. 1−12.
  • Khalfallah S. Explaining the Riddle of Effective Moment of Inertia Models for FRP Concrete Beams. Paper presented at SBEIDCO – 1st International Conference on Sustainable Built Environment Infrastructures in Developing Countries -ENSET Oran (Algeria); 2009 Oct. p. 12-14.
  • Dhanalakshmi G, Subhashini B, Keshanth R, Monisha N, Akila R. Effect of High Performance Concrete in PCC Structure by Partial Replacement of Agricultural Waste, Indian Journal of Science and Technology. 2016 Jan; 9(2):1−5.
  • Yousef Zandi, Yasemin Akgun, Ahmet Durmus. Investigating the use of High Performance Concrete in Partially Prestressed Beams and Optimization of Partially Prestressed Ratio. Indian Journal of Science and Technology. 2012 Jul; 5(7):2991−96.
  • Johnson Bjorgvin Smari. Prestressed BFRP Tendons in Concrete Beam. Master of Science Thesis. Hoskolinnreukjavik University Iceland, 2011.
  • Burgoyne CJ. Ductility and Deformability in Beams Prestressed with FRP Tendons, FRP Composites in Civil Engineering. 2001; 1:15−25.
  • RiyasMoideen KK, Dewangan UK. Effect of Material Nonlinearity on Deflection of Beams and Frames, Indian Journal of Science and Technology. 2016 Jul; 9(28):1−6.


  • There are currently no refbacks.

Creative Commons License
This work is licensed under a Creative Commons Attribution 3.0 License.