Experimental study and analysis on fatigue stiffness of RC beams strengthened with CFRP and steel plate

Abstract

The objective of this work is to investigate the fatigue behavior of reinforced concrete (RC) beams strengthened with externally bonded carbon fiber reinforced polymer (CFRP) and steel plate. An experimental investigation and theoretical analysis were made on the law of deflection development and stiffness degradation, as well as the influence of fatigue load ranges. Test results indicate that the law of three-stage change under fatigue loading is followed by both midspan deflection and permanent deflection, which also have positive correlation with fatigue load amplitude. Fatigue stiffness of composite strengthened beams degrades gradually with the increasing of number of cycles. Based on the experimental results, a theoretical model by effective moment of inertia method is developed for calculating the sectional stiffness of such composite strengthened beams under fatigue loading, and the calculated results are in good agreement with the experimental results.

Keywords

carbon fiber reinforced polymer / steel plate / composite strengthening technique / reinforced concrete beams / fatigue stiffness

References

[1] Al-RousanR., IssaM.. Fatigue performance of reinforced concrete beams strengthened with CFRP sheets [J]. Construction and Building Materials, 2011, 25(8): 3520-3529

[2] FerrierE., BigaudD., ClémentJ. C., HamelinP.. Fatigue-loading effect on RC beams strengthened with externally bonded FRP [J]. Construction and Building Materials, 2011, 25(2): 539-546

[3] OudahF., El-HachaR.. Research progress on the fatigue performance of RC beams strengthened in flexure using fiber reinforced polymers [J]. Composites Part B: Engineering, 2013, 47(4): 82-95

[4] DongJ. F., WangQ. Y., GuanZ. W.. Structural behaviour of RC beams externally strengthened with FRP sheets under fatigue and monotonic loading [J]. Engineering Structures, 2012, 41(8): 24-33

[5] WangS.-y., WangZ.-y.. Mechanism of improving ductility of high strength concrete T-section confined by CFRP sheet subjected to flexural loading [J]. Journal of Central South University, 2013, 20(1): 246-255

[6] CeroniF.. Experimental performances of RC Beams strengthened with FRP materials [J]. Construction and Building Materials, 2010, 24(9): 1547-1559

[7] OudahF., El-HachaR.. A new ductility model of reinforced concrete beams strengthened using fiber reinforced polymer reinforcement [J]. Composites Part B: Engineering, 2012, 43(8): 3338-3347

[8] CeroniF., PecceM., MatthysS., TaerweL.. Debonding strength and anchorage devices for reinforced concrete elements strengthened with FRP sheets [J]. Composites Part B: Engineering, 2008, 39(3): 429-441

[9] ArslanG., SevukF., EkizI.. Steel plate contribution to load-carrying capacity of retrofitted RC beams [J]. Construction and Building Materials, 2008, 22(3): 143-153

[10] LeiD., ChenG.-y., ChenY.-q., RenQ.-w.. Experimental research and numerical simulation of RC beams strengthened with bonded steel plates [J]. Science China Technological Sciences, 2012, 55(12): 3270-3277

[11] AykacS., KalkanI., AykacB., KarahanS., KayarS.. Strengthening and repair of reinforced concrete beams using external steel plates [J]. Journal of Structural Engineering, 2013, 139(6): 929-939

[12] LuY.-y., ZhouT., ZhaoG.-f.. Calculation analysis of resisting flexural strength of RC beams strengthened by combination of CFRP and steel plate [J]. Journal of Hydroelectric Engineering, 2006, 25(3): 77-83

[13] LuY.-y., ZhouT., ZhangW.. Ductility analysis of RC beams strengthened with carbon fiber reinforced polymer and steel plate [J]. Journal of Harbin Institute of Technology, 2006, 38(11): 1939-1942

[14] LuY.-y., ZhouT.. Experimental research on flexural performance of reinforced concrete beams combination strengthened with bonded carbon fiber reinforced polymer and steel plates [J]. Journal of the China Railway Society, 2006, 28(1): 80-87

[15] LuY.-y., ZhouT.. Calculation of sectional stiffness of RC beams combination strengthened with CFRP and steel plates [J]. Journal of the China Railway Society, 2007, 29(1): 72-76

[16] GuoZ.-h.Theories Of Reinforced Concrete [J], 2013BeijingTsinghua University Press

[17] BalaguruP. N., ShahS. P.. A method of predicting crack widths and deflections for fatigue loading [J]. ACI Special Publication, 1982, 75: 153-175

[18] ACI Committee 318-08.Building code requirements for structural concrete [S], 2008107-123

[19] PapakonstantinouC. G., BalaguruP. N., PetrouM. F.. Analysis of reinforced concrete beams strengthened with composites subjected to fatigue loading [J]. ACI Special Publication, 2002, 206: 1-17