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A new innovation of research on the interface slip of concrete beam strengthened with near-surface mounted fiber reinforced plastics bars

ZENG Xiantao1,2 REN Zhenhua1,2 YAN Qian1

(1.Department of Building Engineering, Hunan Institute of Engineering, Xiangtan, Hunan Province, China 411104)
(2.CIC of Wind Power Equipment and Energy Conversion, Xiangtan, Hunan Province, China 411104)

【Abstract】Bonding performance of the interface between FRP bars and concrete is the key of mechanics properties in the concrete structure strengthened with FRP bars. The constitutive relations of the interface bonding performance are described by the interface bond–slip model of FRP–concrete, which predict the stripping damage of FRP–concrete and must determine the appropriate bond–slip model. For the establishment of an interface bond–slip model, a four-point bending test of 11 concrete beams was carried out on the basis of a new test method to study the interface characteristics of reinforced concrete beams with embedded CFRP bars. Based on the shear stress model of the interface between resin bolt and anchoring agent in rock, the analytical expression of the axial normal stress of CFRP bar along the anchorage length of CFRP bar in the cross-section was derived, and the elongation of CFRP bar anchorage segment was obtained. In combination with the measured slip of the specified section of CFRP bar and the elongation of exposed CFRP bar, the slip of the interface between CFRP bar and concrete is obtained, and the bond–slip curve of the interface between CFRP bar and concrete is plotted. The test and analysis of the wide-notch beam show that the bonding shear stress and the slip properties are easy to obtain by the testing system. Bar stress is clear and the average interface shear stress of the CFRP is convenient to obtain. The slip and bond–slip curve is accurate and simple, and the interference of strain gauges is eliminated, so it has demonstrative guidance to the research on the interface properties of CFRP–concrete.

【Keywords】 near-surface mounted fiber reinforced plastic; concrete; interface; constitutive relation; new innovation;

【DOI】

【Funds】 National Natural Science Foundation of China (51678430) Natural Science Foundation Project of Hunan Province, China (2017JJ4016, 2018JJ4042)

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This Article

ISSN:1004-4574

CN: 23-1324/X

Vol 28, No. 04, Pages 13-21

August 2019

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Article Outline

Abstract

  • 1 Thinking of experiments and new methods
  • 2 Determination of slip amount δu in l2 segment
  • 3 Conclusions
  • References