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Numerical Investigation on Structural Behavior of a Lid with Stiffeners for Suction-installed Cofferdams

석션 가물막이 보강 상판의 구조 거동에 대한 수치해석 연구

  • Kim, Jeongsoo (Dept. of Infrastructure Safety Research, Korea Institute of Civil Engineering and Building Technology)
  • 김정수 (한국건설기술연구원 인프라안전연구본부)
  • Received : 2019.08.13
  • Accepted : 2019.10.04
  • Published : 2019.10.31

Abstract

With increasing demand for large offshore infrastructures, suction cofferdams have been large, and the lid stiffener arrangement for a suction cofferdam has become a key element in cofferdam design to constrain the flexural deformation effectively. This study analyzed the changes in the structural behavior of a lid for a suction cofferdam due to lid stiffeners to provide insights into effective stiffener arrangements. By investigating conventional suction anchors, several stiffener patterns of a lid for a polygonal suction cofferdam were determined and analyzed. The structural performance of the stiffened lids was estimated by comparing the stress and deformation, and the reaction distributions on the edge of lid were investigated to analyze the effects of the stiffener arrangement on the lid-wall interface. Finite element analysis showed that radial stiffeners contribute dominantly to decreasing the stress and vertical deflection of the lids, but the stiffeners cause an increase in shear forces between the lid and wall; the forces are concentrated on the lid near the areas reinforced with radial stiffeners, which is negative to lid-wall connection design. On the other hand, inner and outer circumferential stiffeners show little reinforcement effects in themselves, while they can help reduce the stress and deformation when arranged with partial radial stiffeners simultaneously.

대형 해상 구조물 시공이 증가됨에 따라 석션 가물막이 또한 대형화되고 있고, 이로 인해 가물막이 상판의 휨 변형을 효과적으로 억제하기 위한 상판 보강 설계가 가물막이 설계의 핵심적인 요소가 된다. 본 연구는 석션 가물막이 상판의 보강으로 인한 구조 거동 변화를 유한요소모델을 이용해 분석하고, 효과적인 상판 보강 배치 방안 도출을 위한 통찰을 제공하고자 한다. 기존 석션 앵커를 조사하여 각형 석션 가물막이 상판의 여러 보강 유형을 결정하였으며, 각 보강 상판을 분석하였다. 보강 상판의 응력과 변형을 비교하여 구조성능을 평가하였고, 추가로 상판 가장자리의 반력 분포를 분석함으로써 보강재 배치가 상판-케이슨 벽체 연결부에 미치는 영향을 함께 조사하였다. 유한요소해석 결과로부터, 방사방향 보강재가 상판의 처짐 및 응력 감소에 크게 기여한 반면, 상판-벽체 연결부의 수평 전단력을 집중 및 증가시켜 연결부 설계에 불리하게 작용함을 확인할 수 있었다. 또한, 내/외측 환형 보강재는 자체 보강 효과가 미미하나, 부분적으로 배치된 방사 보강재와 함께 연결해 배치되면 응력 및 처짐 개선에 기여함을 알 수 있었다.

Keywords

References

  1. H. S. Jang, Y. I. Jang,, Y. S. Choi, "Case Study on Foundation Design of Over-water Bridge", Technical Magazine of Yooshin, vol.12, no.22, pp.288-297, 2012. (In Korean)
  2. Korea Institute of Civil Engineering and Building Technology (KICT), "Final Report of Research Project on Large Circular Cofferdam Construction for Offshore Bridge Foundation", No.14RDPP-C090994-01, Planning Report, KAIA (Korea Agency for Infrastructure Technology Advancement), Korea, pp.3-7. (In Korean)
  3. S. H. Han, W. S. Park, I. S. Jang, Y. K. Cho, "Application of Suction Pile for Marine and Harbor Structures", Magazine of the Korea Concrete Institute, vol.16, no.6, pp.20-25, 2004. (In Korean)
  4. T. I. Tjelta, "Suction Piles: Their Position and Application Today", Proceedings of 11th International Offshore and Polar Engineering Conference, The International Society of Offshore and Polar Engineers, Norway, pp.1-6, June 2001.
  5. Y. S. Kim, I. S. Jang, "Analysis of Load Capacity and Deformation Behavior of Suction Pile Installed in Sand", Journal of the Korean Geo-Environmental Society, vol.27, no.11, pp.27-37, 2011. (In Korean) DOI: http://dx.doi.org/10.7843/kgs.2011.27.11.027
  6. S. Kim, Y. W. Choo, D. S. Kim, H. G. Sung, "Capacity of Horizontally Loaded Suction Anchor Installed in Silty Sand", Journal of Ocean Engineering and Technology, vol.27, no.1, pp.59-66, 2013. (In Korean) DOI: http://dx.doi.org/10.5574/KSOE.2013.27.1.059
  7. K. Kim, O. Kwon, M. Oh, I. Jang, "Investigation on the Penetration Resistance of Suction Bucket Foundation in Sand Using Model Test", Journal of the Korean Geo-Environmental Society , vol.15, no.6, pp.75-83, 2014. (In Korean) DOI: http://dx.doi.org/10.14481/jkges.2014.15.6.75
  8. D. J. Kim, J. U. Youn, K. Y. Lee, S. H. Jee, Y. W. Choo, "Jacking Penetration Resistance of Bucket Foundations in Silty Sand Using Centrifuge Modelling", Journal of the Korean Geo-Environmental Society, vol.31, no.1, pp.25-35, 2015. (In Korean) DOI: http://dx.doi.org/10.7843/kgs.2015.31.1.25
  9. S. Kim, W. Y. Choo, O. Kwon, D. S. Kim, "Numerical Analysis of Group Suction Anchor of Parallel Arrangement Installed in Sand Subjected to Pullout Load", Journal of the Korean Geo-Environmental Society , vol.30, no.11, pp.61-69, 2014. (In Korean) DOI: http://dx.doi.org/10.7843/kgs.2014.30.11.61
  10. S. H. Na, I. S. Jang, O. Kwon, S. H. Lee, "Study on Pullout Behavior of Embedded Suction Anchors in Sand Using ALE (Arbitrary Lagrangian Eulerian) Technique", Journal of the Korean Society of Civil Engineers, vol.34, no.1, pp.167-173, 2014. (In Korean) DOI: http://dx.doi.org/10.12652/Ksce.2014.34.1.0167
  11. V. Ssenyondo, T. V. An, S. R. Kim, "Numerical Investigation on Seepage Stability of Cut-off Walls", Proceeding of the KSCE Conference, Journal of the Korean Society of Civil Engineers , Korea, pp.1556-1557, 2017.
  12. J. Kim, Y. J. Jeong, M. S. Park, "Estimation on External Forces Applied to Suction Caisson Using Seepage Analysis", Journal of the Korean Society of Civil Engineers , vol.39, no.2, pp.317-325, 2018. (In Korean) DOI: http://dx.doi.org/10.12652/Ksce.2019.39.2.0317
  13. M. Rossow, E. Demsky, R. Mosher, Theoretical Manual for Design of Cellular Sheet Pile Structures (Cofferdams and Retaining Structures), No. WES/TR/ITL-87-5, Army Engineer Waterways Experiment Station, Information Technology Lab, Vicksburg, USA, 1987.
  14. B. S. Bakir, Finite Element Analysis of Cellular Structures Subjected to Wave Loads, Ph.D. Dissertation, Iowa State University, Ames, 1993.
  15. K. J. Wissmann, G. M. Filz, R. L. Mosher, J. R. Martin, "Sheet pile tensions in cellular structures", Journal of Geotechnical and Geoenvironmental Engineering (ASCE), Vol.129, No.3, pp.224-233, 2003. DOI: https://doi.org/10.1061/(ASCE)1090-0241(2003)129:3(224)
  16. J. Kim, Y. J. Jeong, M. S. Park, "Structural Behaviors of Cylindrical Cofferdam with Plane and Corrugated Cross Section under Offshore Conditions", International Journal of Emerging Technology and Advanced Engineering , vol.7, pp.334-340, 2017. DOI: https://doi.org/10.1016/j.engstruct.2013.09.041
  17. S. Madsen, L. V. Andersen, L. B. Park, "Numerical Buckling Analysis of Large Suction Caissons for Wind Turbines on Deep Water", Engineering Structures, vol.57, pp.443-452, 2013. DOI: https://doi.org/10.4236/ojce.2018.84040
  18. J. Kim, Y. J. Jeong, M. S. Park, S. Song, "Structural Analysis of Offshore Cofferdam Subjected to Wave Load and Suction Pressure", Open Journal of Civil Engineering , vol.8, no.4, pp.555-569, 2018. https://doi.org/10.4236/ojce.2018.84040
  19. S. Timoshenko, S. Woninowsky-Krieger, Theory of Plates and Shells, McGraw-Hill, 2nd Edition (Re-issue), pp.51-78, 1987.
  20. L. B. Ibsen, A. Barari, K. A. Larsen, "Adaptive Plasticity Model for Bucket Foundations", Journal of Engineering Mechanics, vol.140, no.2, pp.361-373, 2014. DOI: https://doi.org/10.1061/(ASCE)EM.1943-7889.0000633
  21. S. He, P. Zhang, H. Ding, "Study on the Bearing Mode and Force Transfer Path of Composite Bucket Foundations", Energy (MDPI), Vol.10, No.7, 1041, 2017. DOI: https://doi.org/10.3390/en10071041
  22. S. A. Nielsen, L. B. Ibsen, "The Offshore Bucket Trail Installation", Proceeding of EWEA Offshore 2015, Denmark, 2015.
  23. C. H. Yang, Structural Mechanics, Chung Moon Kack, 4th Edition, p.227, 2005. (In Korean)
  24. M. A. Crisfield, Non-linear Finite Element Analysis of Solids and Structures (Volume 1: Essentials), John Wiley and Sons, pp.65-75, 1991.