Journal of the Computational Structural Engineering Institute of Korea (한국전산구조공학회논문집)

Computational Structural Engineering Institute of Korea (한국전산구조공학회)
권호 표지
DOI QR코드

DOI QR Code

Embedded EM Sensor for Tensile Force Estimation of PS tendon of PSC Girder

PS 긴장재 긴장력 계측을 위한 PSC 거더 내부 매립용 EM 센서

  • Park, Jooyoung (Department of Civil & Environmental System Engineering, Sungkyunkwan Univ.) ;
  • Kim, Junkyeong (Department of Civil & Environmental System Engineering, Sungkyunkwan Univ.) ;
  • Zhang, Aoqi (Department of Civil & Environmental System Engineering, Sungkyunkwan Univ.) ;
  • Lee, Hwanwoo (Department of Civil Engineering, Pukyong National Univ.) ;
  • Park, Seunghee (School of Civil & Architecture Engineering, Sungkyunkwan Univ.)
  • 박주영 (성균관대학교 건설환경시스템공학과) ;
  • 김준경 (성균관대학교 건설환경시스템공학과) ;
  • 장오기 (성균관대학교 건설환경시스템공학과) ;
  • 이환우 (부경대학교 토목공학과) ;
  • 박승희 (성균관대학교 건축토목공학부)
  • Received : 2015.10.15
  • Accepted : 2015.11.23
  • Published : 2015.12.29
Download PDF
⟨ Previous Next ⟩

Abstract

In this paper, an embedded EM sensor was researched to estimate prestressing force of PS tendon in PSC girder. Recent methodologies for managing prestressing force loss were staying on verifying a applying prestressing force under construction, namely the loss management can not be controlled after construction. To estimate the tensile force of PS tendon during lifetime of PSC girder, this research proposed a bobbin-type embedded EM sensor that can be embedded in PSC girder is designed and fabricated considering the shape properties of anchorage zone and sheath. To verify the proposed sensor, a small PSC girder test was performed. The embedded EM sensor was connected to a sheath and anchor block, and the concrete was poured. After curing, the change of the permeability of PS tendon under tensile forces of 200, 710, 1070, 1300kN was measured using embedded EM sensor. The permeability of PS tendon had decreased according to the increment of applied tensile force. Also it is confirmed that the change of permeability due to applied tensile force could resolve the applied tensile force values. As a result, proposed embedded EM sensor could be embed into the PSC girder and it could be used to estimate the tensile force variation during lifetime of PSC girder.

본 논문에서는 PSC 거더 내부 긴장재의 Prestress 변화를 계측하고, 그 손실을 관리하기 위하여 PSC 거더 내부에 매립이 가능한 매립형 EM 센서를 연구 및 제작하였다. 현재까지의 PSC 내부 긴장재의 긴장력 손실관리는 시공 시 설계 긴장력 도입 여부 검증에 머물러 있으며, 시공 후에는 관리가 제대로 이루어지고 있지 않다. 이에 본 논문에서는 강자성체에 자기장이 작용하면 비투자율인 강자성체 고유의 특성이 변화한다는 탄성-자기 이론을 기초로, PSC 거더의 정착구와 쉬스관 외관의 특성을 반영하여 PSC 거더 내부에 매립이 가능한 매립형 EM 센서를 설계하여 제작하였다. 제작 후에는 그 성능을 검증하기 위하여 소형 PSC 거더 모형에 제작된 매립형 EM 센서를 설치한 후 콘크리트를 타설하였다. 양생이 종료된 후 7가닥의 PS 텐던을 삽입한 후 텐던에 200, 710, 1070, 1300kN의 긴장력을 도입하면서 매립형 EM센서를 통해 비투자율의 변화를 계측하였다. 계측 결과 도입한 긴장력이 커질수록 PS 텐던의 비투자율이 낮아지는 변화가 있음을 확인하였으며, 도입 긴장력에 따른 투자율이 도입 긴장력을 충분히 추정할 수 있음을 확인하였다. 따라서 본 연구에서 제안한 매립형 EM 센서는 PSC 교량 내부로 매립이 가능함을 확인하였으며 매립형 EM 센서를 통한 비투자율 변화 계측을 통하여 PS 텐던의 긴장력 변화를 추정할 수 있음을 확인하였다.

Keywords

References

  1. Chen, H.L., Wissawapaisal, K. (2001) Measurement of Tensile Forces in a Seven-wire Prestressing Strands using Stress Waves, ASCE J. Eng. Mech., 127(6), pp.599-606. https://doi.org/10.1061/(ASCE)0733-9399(2001)127:6(599)
  2. Kim, J., Park, J., Zhang, A., Lee, H., Park, S. (2015) Prestressing Loss Management for PSC Girder Tendon Based on EM Sensing, J. Comput. Struct. Eng. Inst. Korea, 28(4), pp.369-374. https://doi.org/10.7734/COSEIK.2015.28.4.369
  3. Kim, J.M., Kim, H.W., Park, Y.H., Yang, I.H., Kim, Y.S. (2012) FBG Sensors Encapsulated into 7-Wire Steel Strand for Tension Monitoring of a Prestressing Tendon, Adv. Struct. Eng., 15(6), pp.907-917. https://doi.org/10.1260/1369-4332.15.6.907
  4. Kim, J.T., Hong, D.S., Park, J.H., Cho, H.M. (2008) Vibration-Based Monitoring of Prestress-Loss in PSC Girder Bridges, J. Comput. Struct. Eng. Inst. Korea, 21(1), pp.83-90.
  5. Kim, J.T., Park, J.H., Hong, D.S., Cho, H.M., Na, W.B., Yi, J.H. (2009) Vibration and Impedance Monitoring for Prestress-loss Prediction in PSC Girder Bridges, Smart Struct. & Sys., 5(1), pp.81-94. https://doi.org/10.12989/sss.2009.5.1.081
  6. Kurokawa, S., Sumitro, S., Wang, M.L. (2001) Stress Measurement of Various Cables by EM Sensor, Proc. of JPCEA 10th Annual Conference, pp.101-106.
  7. Rens, K.L., Wipf, T.J., Klaiber, F.W. (1997) Review of Nondestructive Evaluation Techniques of Civil Infrastructure, ASCE J. Perf. Const. Facil., 11, pp.152-160. https://doi.org/10.1061/(ASCE)0887-3828(1997)11:4(152)
  8. Sumitro, S., Jarosevic, A., Wang, M.L. (2002) Elasto-Magnetic Sensor Utilization on Steel Cable Stress Measurement, The First Fib Congress, Concrete Structures in the 21th Century, Session 15, pp.79-86.
  9. Wang, M.L., Chen, Z. (2000) Magneto-Elastic Permeability Easurement for Stress Monitoring in Steel Tendons and Cables, Proc. of the SPIE 7th Annual Symposium on Smart Structures and Materials, Health Monitoring of the Highway Transportation Infrastructure, 3995, pp.492-500.
  10. Wang, M.L., Lloyd, G.M., Hovorka, O. (2001) Development of a Remote Coil Magneto-Elastic Stress Sensor for Steel Cables, Proc. of the SPIE 8th Annual International Symposium on Smart Structures and Material, Health Monitoring and Management of Civil Infrastructure Systems, Newport Beach CA, 4337, pp.122-128.
  11. Washer, G.A., Green, R.E., Pond, R.B. (2002) Velocity Constants for Ultrasonic Stress Measurement in Prestressing Tendons, Res. Nondestruct. Eval., 14(2), pp.81-94. https://doi.org/10.1080/09349840209409706
  12. Weiher, H., Zilch, K. (2006) Condition of Post-Tensioned Concrete Bridges-Assessment of the German Stock by a Spot Survey of Damages, Proceedings of the First International Conference on Advances in Bridge Engineering, pp.26-28.
  13. Youn, S.G., Kim, E.K. (2006) Deterioration of Bonded Post-Tensioned Concrete Bridges and Research Topics on the Strength Evaluation in ISARC, Proceedings of JSCE-KSCE Joint Seminar on Maintenance and Management Strategy of Infrastructure in Japan and Korea, 7.