A Method for Determination of the Fundamental Period of Layered Soil Profiles

Document Type : Research Paper

Authors

1 Department of Civil Engineering., Faculty of Engineering, University of Ege, Bornova, Izmir, Turkey

2 Department of Civil Engineering., Faculty of Engineering, University of Canakkale Onsekiz Mart, Canakkale, Turkey.

Abstract

In this study, a method is proposed to determine the fundamental period of layered soil profiles. A model considering the layered soil as shear type structure is used. At first, the soil profile is divided into substructures. Then, the stiffness matrices of the substructures considered as the equivalent shear structures are assembled according to the Finite Element Method. Thereinafter, the stiffness matrices of the substructures are transformed into the Modified Finite Element Transfer Matrices, which take part in the literature. Finally, the system matrix is assembled using matrices of the substructures. The proposed method provides reduction in the size of the matrix. Therefore, analysis time is remarkably reduced. At the end of the study, the accuracy of the method is presented by the examples. Consequently, the proposed method offers a practical method for determination of the fundamental period of the soil.

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Main Subjects

[1] Dobry, R.I., Oweis, I., Urzua, A. Simplified procedures for estimating the fundamental period of a soil profile, Bulletin of the Seismological Society of America, 66, 1976, pp. 1293-1321.
[2] Gazetas, G. Vibrational characteristics of soil deposits with variable wave velocity, International Journal for Numerical and Analytical Methods in Geomechanics, 6, 1982, pp. 1-20.
[3] Medina, F. Modeling of layered soil-structure interaction by infinite elements, Earthquake Engineering, Teneth World Conference, Balkema, Roterdam, 1992.
[4] Singh, Y., Nagpal, A.K. Estimatıng fundamental period of soil profiles, Geotechnical Engineering, 24(2), 1977, pp. 167-174.
[5] Sarma, S.K. Analytical solution to the seismic response of visco-elastic soil layers, Géotechnique, 44(2), 1993, pp. 265-275.
[6] Hadjian, A.H. Fundamental period and mode shape of layered soil profiles, Soil Dynamics and Earthquake Engineering, 22, 2002, pp. 885-891.
[7] Sawada, S. A simplified equation to approximate natural period of layered ground on the elastic bedrock for seismic design of structures, 13th World Conference on Earthquake Engineering Vancouver, B.C., Canada, 2004.
[8] Deb, K., Dey, A., Chandra, S. Modeling of layered soil system, 1st Indian Young Geotechnical Engineers Conference, Hyderabad, India, 2-3rd March, 50-55, 2007.
[9] Ruiz, S., Saragoni, S.R. Free vibration of soils during large earthquakes, Soil Dynamics and Earthquake Engineering, 29, 2009, pp. 1-16.
[10] Vijayendra, K.V., Prasad, S.K., Nayak, S. Computation of Fundamental Period of Soil Deposit: A Comparative Study, Oxford, UK, second edition, Indian Geotechnical Conference, December 16-18, 2010.
[11] Choi, M.S. Free Vibration Analysis of Plate Structures Using Finite Element-Transfer Stiffness Coefficient Method, Journal of Mechanical Science and Technology, 17(6), 2003, pp. 805-815.
[12] Rong, B., Rui, X.T., Wang, G.P. Modified Finite Element Transfer Matrix Method for Eigenvalue Problem of Flexible Structures, Journal of Applied Mechanics, 78(2), 2011, 021016.
[13] Ozturk, D., Bozdogan, K., Nuhoglu, A. Modified finite element-transfer matrix method for the static analysis of structures, Structural Engineering and Mechanics, 43(6), 2012, pp. 761-769.
[14] Iyisan, R., Hatipoglu, M., Ozudogru, T.Y. Determination of shear wave velocity by suspension ps logging method, 16th National Congress of Soil Mechanics and Geotechnical Engineering, Erzurum, Turkey, 2016.