Geomechanics and Engineering

  • 제1권3호
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  • Pages.219-239
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  • 2009
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  • 2005-307X(pISSN)
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  • 2092-6219(eISSN)
테크노프레스 (Techno-Press)
권호 표지
DOI QR코드

DOI QR Code

Ratio of predicted and observed natural frequency of finite sand stratum

  • Prathap Kumar, M.T. (G.C.E., Ramanagara, India and UVCE) ;
  • Ramesh, H.N. (Faculty of Engineering (Civil), UVCE, Bangalore University) ;
  • Raghavendra Rao, M.V. (Faculty of Engineering (Civil), UVCE, Bangalore University) ;
  • Raghunandan, M.E. (UVCE)
  • 투고 : 2009.04.24
  • 심사 : 2009.08.20
  • 발행 : 2009.09.25
⟨ 이전 논문 다음 논문 ⟩

초록

Vertical vibration tests were conducted using model footings of different size and mass resting on the surface of finite sand layer with different height to width ratios and underlain by either rigid concrete base or natural red-earth base. A comparative study of the ratio of predicted and observed natural frequency ratio of the finite sand stratum was made using the calculated values of equivalent stiffness suggested by Gazetas (1983) and Baidya and Muralikrishna (2001). Comparison of results between model footings resting on finite sand stratum underlain by the rigid concrete base and the natural red-earth base showed that, the presence of a finite base of higher rigidity increases the resonant frequency significantly. With increase in H/B ratio beyond 2.0, the influence of both the rigid concrete and natural red-earth base decreases. Increase in the contact area of the footing increases the resonant frequency of the model footings resting on finite sand stratum underlain by both the types of finite bases. Both the predicted and the observed resonant frequency ratio decreases with increase in force rating and height to width ratio for a given series of model footing.

키워드

참고문헌

  1. Al-Homoud, A.S. and Al-Maaitah, O.N. (1996), "An experimental investigation of vertical vibration of model footings on sand", J. Soil Dyn. Earthq. Eng., 15, 431-445. https://doi.org/10.1016/0267-7261(96)00023-1
  2. Baidya, D.K. and Sridharan, A. (2002), "Foundation Vibration on Layered Soil System", Indian Geotech. J., 32(2), 236-257.
  3. Baidya, D.K. and Muralikrishna, G. (2001), "Investigation of resonant frequency and amplitude of vibrating footing resting on a layered soil system", Geotech. Test. J., 24(4), 409-417. https://doi.org/10.1520/GTJ11138J
  4. Baidya, D.K. and Rathi, A. (2004), "Dynamic response of footings resting on a sand layer of finite thickness", J. Geotech. Geoenviron., 130(6), 651-655. https://doi.org/10.1061/(ASCE)1090-0241(2004)130:6(651)
  5. Baidya, D.K., Muralikrishna, G. and Pradhan, P.K. (2006), "Investigation of the foundation vibrations resting on a layered soil system", J. Geotech. Geoenviron., 132, 116-123. https://doi.org/10.1061/(ASCE)1090-0241(2006)132:1(116)
  6. Gazetas, G. and Rosset, J.M. (1979), "Vertical Vibration of machine foundations", J. Geotech. Eng. Div., ASCE, 105(12), 1435-1454.
  7. Gazetas, G. (1983), "Analysis of machine foundations: state of the art", J. Soil Dyn. Earthq. Eng., 2(1), 2-42.
  8. Gazetas, G. (1991), "Formulae and charts for impedances of surface and embedded foundations", J. Geotech. Eng. Div., ASCE, 117(9), 1363-1381. https://doi.org/10.1061/(ASCE)0733-9410(1991)117:9(1363)
  9. Hardin, B.O. and Drenevich, V.P. (1972), "Shear modulus and damping in soils: design equations and curves", J. Soil Mech. Found. Eng. Div., ASCE, 98(6), 603-624.
  10. Kagawa, T. and Kraft, L.M., Jr. (1981), "Machine foundations on layered soil deposits", Proceedings of the 10th International Conference on Soil Mechanics and Foundation Engineering, Stockholm, June.
  11. Lysmer, J. (1965), "Vertical motion of rigid footing", U.S. Army Engineer Waterways Experiment Station. Report No.3-115, Vicksburg, Mississippi.
  12. Lysmer, J. and Richart, F.E., Jr. (1966), "Dynamic response of footings to vertical loading", J. Soil Mech. Found. Eng. Div., ASCE, 92(1), 65-91.
  13. Reissner, E. (1936), "Stationare, axial symmetrische durch eine schuttelnde masse erregate shwingungen eines homogene elastischen halbraums", Ingeniur-Archiv, 7, 681-396.
  14. Mandal, A. and Baidya, D.K. (2004), "Effect of presence of rigid base within the soil on the dynamic response of rigid surface foundation", Geotech. Test. J., 27(5), 475-482.
  15. Nagendra, M.V. and Sridharan, A. (1982), "Stiffness coefficients of an elastic medium", J. Geotech. Eng. Div., 108(4), 661-668.
  16. Richart, F.E., Jr, Hall, J.R. and Woods, R.D. (1970), Vibrations of Soils and Foundations. Prentice Hall. Englewood Cliffs, NJ.
  17. Sridharan, A., Gandhi, N.S.V.V.S.J. and Suresh, S. (1990), "Stiffness coefficients of layered soil systems", J. Geotech. Eng. Div., ASCE, 116(4), 604-624. https://doi.org/10.1061/(ASCE)0733-9410(1990)116:4(604)
  18. Whitman, R.V. and Richart, F.E., Jr. (1967), "Design procedures for dynamically loaded foundations", J. Soil Mech. Found. Eng., ASCE, 93(6), 169-193.