Finite Element Assessment on Bond Behavior of FRP-to-Concrete Joints under Cyclic Loading

Authors: F. Atheer, Al-Saoudi, Robin Kalfat, Riadh Al-Mahaidi

Abstract:

Over the last two decades, externally bonded fiber reinforced polymer (FRP) composites bonded to concrete substrates has become a popular method for strengthening reinforced concrete (RC) highway and railway bridges. Such structures are exposed to severe cyclic loading throughout their lifetime often resulting in fatigue damage to structural components and a reduction in the service life of the structure. Since experimental and numerical results on the fatigue performance of FRP-to-concrete joints are still limited, the current research focuses on assessing the fatigue performance of externally bonded FRP-to-concrete joints using a direct shear test. Some early results indicate that the stress ratio and the applied cyclic stress level have a direct influence on the fatigue life of the externally bonded FRP. In addition, a calibrated finite element model is developed to provide further insight into the influence of certain parameters such as: concrete strength, FRP thickness, number of cycles, frequency, and stiffness on the fatigue life of the FRP-toconcrete joints.

Keywords: FRP, concrete bond, control, fatigue, finite element model.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1110654

References:

[1] Galal, K. and A. Mofidi, Shear strengthening of RC T-beams using mechanically anchored unbonded dry carbon fiber sheets. Journal of Performance of Constructed Facilities, 2009. 24(1): p. 31-39.
[2] Al-Mahaidi, R. and R. Kalfat, Investigation into CFRP laminate anchorage systems utilising bi-directional fabric wrap. Composite Structures, 2011. 93(4): p. 1265-1274.
[3] Kalfat, R., R. Al-Mahaidi, and S.T. Smith, Anchorage devices used to improve the performance of reinforced concrete beams retrofitted with FRP composites: State-of-the-art review. Journal of Composites for Construction, 2011.
[4] Kalfat, R. and R. Al-Mahaidi, Finite element investigation into the size effect of bidirectional fibre patch anchors used to enhance the performance of FRP-to-concrete joints. Composite Structures, 2015. 121: p. 27-36.
[5] Kalfat, R. and R. Al-Mahaidi, Investigation into bond behaviour of a new CFRP anchorage system for concrete utilising a mechanically strengthened substrate. Composite structures, 2010. 92(11): p. 2738- 2746.
[6] Kalfat, R., R. Al-Mahaidi, and G. Williams, Investigation of Efficient Anchorage Systems for Shear and Torsion Retrofitting of Box Girder Bridges. ACI Special Publication, 2011. 275.
[7] Červenka, V. and L. Jendele, ATENA Program Documentation Part. 2000.
[8] Kalfat, R. and R. Al-Mahaidi, Finite Element and Experimental Investigation into Patch Anchor Sizes Used to Enhance the Bond Performance of FRP-to-Concrete Joints. Special Publication, 2015. 301: p. 1-16.
[9] Dobromil, P., C. Jan, and P. Radomir, Material model for finite element modelling of fatigue crack growth in concrete. Procedia engineering, 2010. 2(1): p. 203-212.
[10] Taerwe, L. and S. Matthys, Fib model code for concrete structures 2010. 2013: Ernst & Sohn, Wiley.