Journal of the Architectural Institute of Korea Structure & Construction (대한건축학회논문집:구조계)

Architectural Institute of Korea (대한건축학회)
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Strengthening Depth Effect in Externally Post-tensioning Shear Strengthening of Pre-cracked Reinforced Concrete Beam

사전균열이 발생한 철근콘크리트 보의 외적 포스트텐셔닝 전단보강에서 보강깊이의 효과

  • 이수헌 (경북대학교 융복합시스템공학부) ;
  • 신경재 (경북대학교 건설환경에너지공학부) ;
  • 이희두 (경북대학교 건설환경에너지공학부)
  • Received : 2018.07.31
  • Accepted : 2018.11.07
  • Published : 2018.11.30
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Abstract

This paper presents the shear strengthening effect of externally post-tensioning (EPT) method using high-strength steel rod in pre-cracked reinforced concrete (RC) beams. Three- and four-point bending tests were performed on a total of 8 specimens by adjusting the strengthening depths in the deviator position of EPT. The effective strengthening depths were 435, 535, and 610 mm. The pre-loading up to about 2/3 of ultimate load capacity measured in unstrengthened RC beam were applied in the beam to be post-tensioned. The EPT method was then applied to the pre-damaged RC beams and re-loading was added until the end of the test. EPT restored deflections of 3 mm or more, which account for about 40% of deflection when the pre-loading was applied. The shear strengthening increases more than 3 times and 36~107% in terms of the stiffness and load-carrying capacity compared to unstrengthening RC beams. The increased load-carrying capacities of the post-tensioned beam with strengthening depths of 435 and 535 mm are almost the same as 36~61%, and those of 610 mm are 84~107%, which shows the greatest shear strengthening effect.

Keywords

Acknowledgement

Supported by : 한국연구재단

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