Journal of South China University of Technology (Natural Science Edition) ›› 2007, Vol. 35 ›› Issue (10): 198-204.

• Electronics, Communication & Automation Technology • Previous Articles     Next Articles

Fatigue Lives of RC Beams Strengthened with Carbon Fiber Laminates Under Bending Loads

Huang Pei-yan  Zhou Xu-ping  Yang Yi  Niu Peng-zhi  Zheng Shun-chao   

  1. School of Traffic and Communications , South China Univ. of Tech. , Guangzhou 510640 , Guangdong , China
  • Received:2007-03-01 Online:2007-10-25 Published:2007-10-25
  • Contact: Huang Pei-yan (born in 1952- ),male, professor,Ph.D.tutor ,mainly researches on fatigue and fracture mechanics ,strengthening mats.& tech. for bridge. E-mail:pyhuang@scut. edu. cn
  • About author:Huang Pei-yan (born in 1952- ),male, professor,Ph.D.tutor ,mainly researches on fatigue and fracture mechanics ,strengthening mats.& tech. for bridge.
  • Supported by:

    Supported by National Natural Science Foundation of China (10672060 ,10272047)

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Abstract:

The fatigue behavior of RC (Reinforced Concrete) beams strengthened with FRP (Fiber Reinforced Polymer ) is an important subject in civil engineering in the world. In this paper , 18 RC beams (1850 mm x100 mm x 200 mm) strengthened with CFLs (Carbon Fiber Laminates) are divided into 4 groups and are tested to investigate their fatigue behaviors under bending loads. Based on the data of fatigue test and theoretical analyses , S-N and P-S-N curves of the RC beams strengthened with CFLs are obtained according to the new conceptions of permissive and extreme fatigue lives , finding that the ratios of the permissive and extreme fatigue strength to the ultimate static strength are respectively 65% and 67%. The relationships among the mid-span deflection , the loading cycle number, the individual fatigue life and the stress level are then deduced and validated. Afterwards , a new method that only needs some nondestructive experimental data of fatigue (the fatigue load cycles n recommended here is 100 - 1000) is proposed to predict the individual fatigue life. The proposed prediction method is finally validated by the fatigue tests of another three RC beams strengthened with CFLs.

Key words: carbon fiber laminate, reinforced concrete beam, S-N curve, fatigue life prediction, bending load