A Modification to ACI 440.1R-06 Equation for Determining the Bond Strength of GFRP Bars Using Reliability Analysis

Document Type : Research Article


1 Ph.D Student, Department of Civil Engineering, Ferdowsi University, Mashhad, Iran

2 Professor, Department of Civil Engineering, Ferdowsi University, Mashhad, Iran

3 Assistant Professor, Department of Civil Engineering, University of Sistan and Baluchestan, Zahedan, Iran


ACI 440.1R-06 Code overestimates the bond strength of lap-spliced FRP reinforced concrete beams. In this code, the effect of transverse reinforcement along the splice length on bond strength is not taken into account. In this paper, ACI 440.1R-06 equation was modified for calculating the bond strength of spliced bars in specimens without transverse reinforcement along the splice length using reliability analysis and experimental results. Then, 13 beam specimens were manufactured and tested for evaluating the effect of transverse reinforcement on bond strength. Experimental results show that the influence of transverse reinforcement depends on surface geometries of FRP bars. In this study, the bond strength produced by transverse reinforcement is formulated as a function of surface geometries of bars. This equation is obtained by means of experimental results and Monte Carlo simulation. The bond strength calculated by the proposed equations correlates well with the experimental results in comparison with the values predicted by the code provisions.


[1]He, Z., and Tian, G., “Reliability Based Bond Design for GFRP-Reinforced Concrete”, Material and Structures, in press, 2011.
[2]American Concrete Institute (ACI). ,“Guide for the design and construction of structural concrete reinforced with FRP bars”, ACI440.1R-06, Farmington Hills, Mich, 2006.
[3]Harajli, M., and Abouniaj, M. ,“Bond Performance of GFRP Bars in Tension: Experimental Evaluation and Assessment of ACI 440 Guidelines”, Journal of Composites for Construction, Vol. 14, No. 6, pp. 659-668, 2010.
[4]Mosley, C.P., Tureyen, A.K., and Frosch, R.J.,“Bond Strength of Nonmetallic Reinforcing Bars”, ACI Structural Journal, Vol. 105, No. 5, pp. 634-642, 2008.
[5]Darwin, D., Idun, E.K., Zou, J., and Tholen, M.L. ,“Reliability – Based Strength Reduction Factor for Bond”, ACI Structural Journal, Vol. 95, No. 4, pp. 434-443, 1998.
[6]Wambeke, B., and Shield, C. ,“Development Length of Glass Fiber Reinforced Polymer Bars in Concrete”, ACI Structural Journal, Vol. 103, No. 1, pp. 11-17, 2006.
[7]Aly, R. ,“Experimental and Analytical Studies on Bond Behavior Of Tensile Lap Spliced FRP Reinforcing Bars in Concrete”, Ph.D Thesis, University of Sherbrook, Canada, 2005.
[8]Orangun, C.O., Jirsa, J.O., and Breen, J.E.,“Reevaluation of Test Data on Development Length and Splices”, ACI JOURNAL, Proceedings Vol. 74, No. 3, pp. 114-122, 1977.
[9]Mosley, C.P. ,“Bond Performance of Fiber Reinforcing Plastic (FRP) Reinforcement in Concrete”, MS. Thesis, Purdue University, West Lafayette, Lnd, 2002.
[10]CAN/CSA-S6-00 ,“Canadian Highway Bridge Design Code”, Canadian Standards Association, Rexdale, Ontario, Canada, pp. 192, 2000.
[11]Tighiouart, B., Benmokrane, B., and Mukhopadhyaya, P. ,“Bond Strength of Glass FRP Rebar Splices in Beams under Static Loading”, Construction and Building Materials, Vol. 13, pp. 383-392, 1999.
[12]Val, D.V., and Chernin, L. ,“Serviceability Reliability of Reinforced Concrete Beams with Corroded Reinforcement”, Journal of Structural Engineering, Vol. 135, No. 8, pp. 896 – 905, 2009.
[13]Lee, J.O., Yang, Y.S., and Ruy, W.S. ,“A Comparative Study on Reliability - Index and Target - Performance-Based Probabilistic Structural Design Optimization”, Computers and Structures, Vol. 80, pp. 257 – 269, 2002.