Effect of Foundation Width on Subgrade Reaction Modulus
Structures are subjected to vertical and horizontal loads. Vertical subgrade reaction acts on the foundation bottom surface, and in the case of an embedded structure, horizontal subgrade reaction acts on the embedded part. The subgrade reaction is obtained by multiplying the displacement of the foundation by the Subgrade Reaction Modulus (SRM). In practice, SRM is calculated using an equation that incorporates the negative power relationship of the Foundation Width (FW). If the structure is evaluated to be poorly seismic resistant, it is necessary to widen FW. However, when the FW is widened, the design value of SRM decreases. In this case, it is not possible to expect an increase in the subgrade reaction proportional to the increase of FW. Therefore, when the inertia force is very high, the FW has to be very wide. However, underestimating SRM can lead to structural overdesign. In this study, the relationship between SRM and FW, for a structure in which vertical and horizontal load act simultaneously, was analyzed. Compared with the design practice assumptions, the horizontal SRM was found to be highly dependent on FW while the vertical SRM was shown to be less dependent on FW.
M. A. Biot, "Bending of an Infinite Beam on an Elastic Foundation," Journal of Applied Mathematics and Mechanics, no. 203, pp. A1-A7, Mar. 1937.
K. Terzaghi, "Evalution of Conefficients of Subgrade Reaction," Géotechnique, vol. 5, no. 4, pp. 297-326, Dec. 1955. DOI: https://doi.org/10.1680/geot.19184.108.40.2067
A. B. Vesic, "Beams on Elastic Subgrade and the Winkler's Hypothesis," in Proceedings of 5th International Conference of Soil Mechanics, 1963, pp. 845-850.
T. Yoshinaka, "Subgrade reaction coefficient and its correction based on the loading width," PWRI Report 299, 1967.
R. Ziaie-Moayed and M. Janbaz, "Effective Parameters on Modulus of Subgrade Reaction in Clayey Soils," Journal of Applied Sciences, vol. 9, pp. 4006-4012. DOI: https://doi.org/10.3923/jas.2009.4006.4012
J. Lee and S. Jeong, "Experimental Study of Estimating the Subgrade Reaction Modulus on Jointed Rock Foundations," Rock Mechanics and Rock Engineering, vol. 49, no. 6, pp. 2055-2064, Jun. 2016. DOI: https://doi.org/10.1007/s00603-015-0905-9
Specifications for Highway Bridges, Part IV, Substructures. Japan Road Association, 2016.
T. Nagao and D. Shibata, "Experimental Study of the Lateral Spreading Pressure Acting on a Pile Foundation During Earthquakes," Engineering, Technology & Applied Science Research, vol. 9, no. 6, pp. 5021-5028, Dec. 2019. DOI: https://doi.org/10.48084/etasr.3217
T. Nagao, "An Experimental Study on the Way Bottom Widening of Pier Foundations Affects Seismic Resistance," Engineering, Technology & Applied Science Research, vol. 10, no. 3, pp. 5713-5718, Jun. 2020. DOI: https://doi.org/10.48084/etasr.3590
J. H. Michell, "On the Direct Determination of Stress in an Elastic Solid, with application to the Theory of Plates," Proceedings of the London Mathematical Society, vol. s1-31, no. 1, pp. 100-124, 1899. DOI: https://doi.org/10.1112/plms/s1-31.1.100
T. Kimura, "Analytical investigation on mechanical behaviors of two-layer systems," Proceedings of the Japan Society of Civil Engineers, vol. 1969, no. 162, pp. 31-48, Feb. 1969. DOI: https://doi.org/10.2208/jscej1969.1969.162_31
Technical standards and commentaries for port and harbour facilities in Japan. Overseas Coastal Area Development Institute of Japan, 2009.
T. Imai and K. Tonouchi, "Correlation of N-value with S−wave velocity and shear modulus," in Proceedings of the 2nd ESPT, Rotterdam, Netherlands, 1982, pp. 67-72.
I. Suetomi and N. Yoshida, "Nonlinear Behavior of Surface Deposit during the 1995 Hyogoken-Nambu Earthquake," Soils and Foundations, vol. 38, Supplement, pp. 11-22, Sep. 1998. DOI: https://doi.org/10.3208/sandf.38.Special_11
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