Journal of the Korea institute for structural maintenance and inspection (한국구조물진단유지관리공학회 논문집)

Korea Institute for Structural Maintenance Inspection (한국구조물진단유지관리공학회)
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Study on Cracking Causes and Patterns in Median Barrier and Guardrail Concrete in RC Bridge

콘크리트 교량 방호벽의 균열원인 및 패턴 분석에 대한 연구

  • 최세진 ((재)포항산업과학연구원, 강구조연구소) ;
  • 최정욱 (KCI 공학연구소) ;
  • 권성준 (한남대학교 건설시스템공학과)
  • Received : 2014.04.09
  • Accepted : 2014.05.30
  • Published : 2014.09.30
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Abstract

Concrete guide rail and median barrier are an attached RC member, however they are vulnerable to cracking due to slip form construction and large surface of member. In this study, causes and pattern of cracking are analyzed through assessment and NDT (Non-Destructive Technique) evaluation for concrete guide rail and median barrier on highway structure. For this work, analysis on drying shrinkage and hydration heat are performed considering installation period, and plastic shrinkage is also analyzed considering their environmental conditions. From the evaluation, plastic settlement around steel location, drying/ plastic shrinkage, and aggregate segregation are inferred to be the main causes of cracking in the structures. The crack causes and patterns are schematized and techniques of crack-control are suggested. Furthermore concrete guide rail/ median barrier in the bridge on the sea are vulnerable to cracking at early age so that special attentions should be paid at the stages of material selection and construction.

콘크리트 방호벽 및 중앙분리대는 교량의 부속시설이지만, 슬립폼 시공과 넓은 비표면적으로 인해 초기재령 균열이 발생하기 쉽다. 본 연구에서는 대형 교량의 방호벽과 중앙분리대 콘크리트의 외관조사 및 비파괴실험을 수행하여 균열의 원인과 발생 균열의 패턴을 분석하였다. 이를 위해 시공기간을 고려하여, 건조수축, 수화열 해석이 수행되었으며, 현장의 환경조건을 고려하여 소성수축 특성을 평가하였다. 평가결과 대상구조물의 균열 원인은 철근위치에 따른 소성침하균열, 소성수축 및 건조수축에 의한 복부균열, 재료분리에 따른 상부균열로 추정할 수 있었다. 또한 균열원인과 발생 패턴을 도식화하였으며, 시공 및 재료분야에서 균열제어대책을 제안하였다. 해상위 교량에 설치하는 중앙분리대 및 방호벽 콘크리트는 환경조건 (풍속, 온도, 습도)에 매우 민감하여 초기재령균열이 쉽게 발생하므로 재료선택 및 시공방법에 신중을 기해야 한다.

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References

  1. Almusallam, A. A. (2001), Effect of environmental conditions on the properties of fresh and hardened concrete, Cement and Concrete Composites, 23(4-5), 353-361. https://doi.org/10.1016/S0958-9465(01)00007-5
  2. Emmons, P. H. (1994), Concrete Repair and Maintenance Illustrated, R.S. Means Company, 5-16.
  3. Jeon, S. J., Choi, M. S., Kim, Y. J. (2007a), Failure mode of concrete barrier, Proceedings of KCI, 19(2), 329-332 (in Korean).
  4. Jeon, S. J., Choi, M. S., Kim, Y. J. (2008), Test level of domestic concrete barrier, Proceedings of KCI, 20(1), 113-116 (in Korean).
  5. Jeon, S. J., Choi, M. S., Kim, Y. J., Hyun, B. H. (2007b), Static test of precast concrete barrier-I Ultimate behavior and test level, Journal of KSCE, 27(6A), 891-899 (in Korean).
  6. KISTEC-Korea Infrastructure Safety Corporation (1999), Guidelines for Crack Evaluation and Repair/ Restrengthening in Reinforced Concrete Structures, TS-99-R5-010, 12 (in Korean).
  7. Korea Remicon Association (2005), Improvement of Durability and Long Service-Life for Concrete Structure, Technical Report, 105-192.
  8. Kwon, S. J., Na, U. J., Park, S. S., Jung, S. H. (2009), Service life prediction of concrete wharves with early-aged crack : probabilistic approach for chloride diffusion, Structural Safety, 31(1), 75-83. https://doi.org/10.1016/j.strusafe.2008.03.004
  9. Kwon, S. J., Park, S. S., Nam, S. H., Cho, H. J. (2007), A study on survey of carbonation for sound, cracked, and joint concrete in RC Column in Metropolitan City, Journal of the Korea Institute for Structural Maintenance and Inspection, 11(3), 116-122 (in Korean).
  10. Na, U. J., Kwon, S. J., Chaudhuri, S. R., Shinozuka, M. (2012), Stochastic model for service life prediction of RC structures exposed to carbonation using random field simulation, KSCE Journal of Civil Engineering, 16(1), 133-143. https://doi.org/10.1007/s12205-012-1248-7
  11. NCHRP-National Cooperative Highway Research Program (2006), Report 500-Guidance for Implementation of the AASHTO Strategic High Way Safety Plan, TRB Board, 12-56.
  12. Park, S. S., Kwon, S. J., Jung, S. H. (2012b), Analysis technique for chloride penetration in cracked concrete using equivalent diffusion and permeation, Construction and Building Materials, 29(2), 183-192. https://doi.org/10.1016/j.conbuildmat.2011.09.019
  13. Park, S. S., Kwon, S. J., Jung, S. H., Lee, S. W. (2012a), Modeling of water permeability in early aged concrete with cracks based on micro pore structure, Construction and Building Materials, 27(1), 597-604. https://doi.org/10.1016/j.conbuildmat.2011.07.002
  14. Park, S. S., Kwon, S. J., Song, H. W. (2011), Analysis technique for restrained shrinkage of concrete containing chlorides, Materials and Structures, 44(2), 475-486. https://doi.org/10.1617/s11527-010-9642-4
  15. Park, S. W., Park, S. S., Hwang, I. B., Cha, S. J., (2012), A case study on cause analysis for longitudinal crack of duct slab in tunnel, Journal of the Korea Institute for Structural Maintenance and Inspection, 16(5), 19-28 (in Korean). https://doi.org/10.11112/jksmi.2012.16.5.019
  16. Ross, H. E. Sicking, Jr., D. L., Zimmer R. A., Michie, J. D. (1993), Recommended Procedures for the Safety Performance Evaluation of highway Feature, NCHRP report, TBR Board. 85-104.
  17. Song, H. W., Kwon, S. J., Byun, K. J., Park, C. K. (2006), Predicting carbonation in early-aged cracked concrete, Cement and Concrete Research, 36(5), 979-989. https://doi.org/10.1016/j.cemconres.2005.12.019
  18. Woo, K. S., Lee, G. D., Kim, S. U., Ko, M. G. (2000), Safety evaluation of concrete median barrier by computer simulation, Proceedings of KSCE, 1(2), 315-324 (in Korean).