Structural Engineering and Mechanics

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Mechanical behaviour between adjacent cracks in CFRP plate reinforced RC slabs

  • Yuan, Xin (School of Civil Engineering, Suzhou University of Science and Technology) ;
  • Bai, Hongyu (School of Civil Engineering, Suzhou University of Science and Technology) ;
  • Sun, Chen (School of Science, Nanjing University of Science and Technology) ;
  • Li, Qinqing (School of Civil Engineering, Suzhou University of Science and Technology) ;
  • Song, Yanfeng (School of Civil Engineering, Suzhou University of Science and Technology)
  • Received : 2021.10.26
  • Accepted : 2022.09.18
  • Published : 2022.11.10
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Abstract

This paper discussed and analyzed the interfacial stress distribution characteristic of adjacent cracks in Carbon Fiber Reinforced Polymer (CFRP) plate strengthened concrete slabs. One un-strengthened concrete test beam and four CFRP plate-strengthened concrete test beams were designed to carry out four-point flexural tests. The test data shows that the interfacial shear stress between the interface of CFRP plate and concrete can effectively reduce the crack shrinkage of the tensile concrete and reduces the width of crack. The maximum main crack flexural height in pure bending section of the strengthened specimen is smaller than that of the un-strengthened specimen, the CFRP plate improves the rigidity of specimens without brittle failure. The average ultimate bearing capacity of the CFRP-strengthened specimens was increased by 64.3% compared to that without CFRP-strengthen. This indicites that CFRP enhancement measures can effectively improve the ultimate bearing capacity and delay the occurrence of debonding damage. Based on the derivation of mechanical analysis model, the calculation formula of interfacial shear stress between adjacent cracks is proposed. The distributions characteristics of interfacial shear stress between certain crack widths were given. In the intermediate cracking region of pure bending sections, the length of the interfacial softening near the mid-span cracking position gradually increases as the load increases. The CFRP-concrete interface debonding capacity with the larger adjacent crack spacing is lower than that with the smaller adjacent crack spacing. The theoretical calculation results of interfacial bonding shear stress between adjacent cracks have good agreement with the experimental results. The interfacial debonding failure between adjacent cracks in the intermediate cracking region was mainly caused by the root of the main crack. The larger the spacing between adjacent cracks exists, the easier the interfacial debonding failure occurs.

Keywords

Acknowledgement

This work was financially supported by the Brand Professional Funding Project of Jiangsu Province (Grant No. PPZY2015B143), the National Natural Science Foundation of China (Grant No. 51508368), the Science and Technology Project of Housing and Urban-Rural Development Department of Jiangsu Province(Grant No.2019ZD010), the Jiangsu Postgraduate Research and Innovation Program (Grant No. KYCX21_3027), the Jiangsu Province Graduate Student Practice Innovation Program Project (Grant No. SJCX21_1416), and the Key Project of Innovation and Entrepreneurship of College students in Jiangsu Province (Grant No. 201810332019Z).

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