Effective Stress-Based Seismic Analysis of Offshore Wind Turbine Support Structure Considering Wind Load Effects

풍하중 효과를 고려한 해상풍력 지지구조물의 유효응력기반 지진해석

  • 김소연 (군산대학교, 해양산업공학과) ;
  • 김동현 (군산대학교, 건축해양건설융합공학부)
  • Received : 2017.10.11
  • Accepted : 2017.12.27
  • Published : 2018.03.31

Abstract

In this study, seismic analysis of a 3 MW offshore wind turbine support structure was performed by considering the effective stress effect of ground soil and wind load. The pore water pressure was distributed to consider the effective stress effect. A simple formula by Byrne (1991) was used to estimate some parameters and applied to the Finn model. In this paper, seismic analysis based on the total stress and effective stress of the ground was performed, and the responses of offshore wind turbine support structures were compared. In addition, the effect of wind and earthquake load on the ground was also confirmed. As a result of the analysis, the relative displacement is larger in the effective stress analysis, and the displacement difference is larger when the wind load and seismic load are considered simultaneously. It was shown from the results that the effective stress of ground soil should be considered to obtain more reliable responses for offshore wind turbine support structures.

Keywords

Acknowledgement

Supported by : 한국연구재단

References

  1. Seo, Y. H., Kim, S. R., and KIM, B. G., 2016, "Dynamic Model of a Offshore Wind Turbine with a Supporting Structure with Suction Buckets for Prediction of Natural Frequencies," Journal of Wind Energy, Vol. 7, No. 2, pp. 29-34 (in Korean).
  2. Seo, M. Y., Lee, J. S., and Ryu, M. S., 2017, "Analysis of laterally loaded suction pile foundation," Journal of Wind Energy, Vol. 8, No. 1, pp. 55-62 (in Korean).
  3. Lee, S. G., Kim, D. H., and Yoon, G. L., 2013, "Seismic Fragility for 5MW Offshore Wind Turbine using Pushover Analysis," Journal of Ocean Engineering and Technology, Vol. 27, No. 4, pp. 98-106 (in Korean). https://doi.org/10.5574/KSOE.2013.27.4.098
  4. Lee, G. N. and Kim, D. H., 2015, "Seismic Reliability Analysis of Offshore Wind Turbine Support Structure," Journal of Ocean Engineering and Technology, Vol. 29, No. 5, pp. 98-106 (in Korean).
  5. Ministry of Oceans and Fisheries, 2014, Engineering Standards Commentaries Port and Harbor Facilities.
  6. Prevost. J.H., 1986, "Effective Stress Analysis of Seismic Site Response," International Journal for Numerical and Analytical Methods in Geomechanics, Vol. 10, pp. 653-665. https://doi.org/10.1002/nag.1610100607
  7. Finn, W. D. L. and Byrne, P.M., 1976, "Estimating Settlements in Dry Sands During Earthquakes", Canadian Geotechnical Journal, Vol. 13, No.4, pp. 355-363. https://doi.org/10.1139/t76-037
  8. Itasca Consulting Group, Inc, 2012, FLAC 3D - Fast Lagrangian Analysis of Continua in Three Dimensions Ver. 5.0.
  9. Martin, G. R., Finn, W. D. L. and Seed, H. B., 1975, "Fundamentals of Liquefaction Under Cyclic Loading", Journal of the Geotechnical Division, Vol. 101, No. 6, pp. 423-438.
  10. Byrne, P., 1991, "A Cyclic Shear-Volume Coupling and Pore-Pressure Model for Sand," Proceedings of the Second International Conference on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics, St.Louis, USA, Paper No. 1.24, pp. 47-55.
  11. Masing, G., 1926, "Eigenspannungen und Verfestigung beim Messing", Proceedings of the Second International Congress of Applied Mechanics, Zurich, Switzerland, pp. 332-335.
  12. Seed, H. B. and Idriss, I. M., 1970, Soil moduli and damping factors for dynamic response analyses, Report No. EERC 70-10, Earthquake Engineering Research Center' University of California, Berkeley, p. 40.
  13. Sun, J. I., Golesorkhi, R., and Seed, H. B., 1988, Dynamic moduli and damping ratios for cohesive soils, Report No. EERC 88-15, Earthquake Engineering Research Center, University of California, Berkeley, p. 96.
  14. International Electrotechnical Commission (IEC), 2005. IEC 61400-1 Ed. 3, Wind turbines-Part 1:Design requirements.