A further study about the behaviour of foundation piles and beams in a Winkler-Pasternak soil

MARTA B. ROSALES; CARLOS P. FILIPICH

INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2002 vol. 44 p. 21 - 36

0020-7403

The natural vibrations and critical loads of foundation beams embedded in a soil simulated with two elastic parameters through the Winkler?Pasternak (WP) model are analysed. General end supports of the beam are considered by introducing elastic constraints to transversal displacements and rotations. The solution is tackled by means of a direct variational methodology previously developed by the authors who named it as whole element method. The solution is stated by means of extended trigonometric series. This method gives rise to theoretically exact natural frequencies and critical loads. A particular behaviour arises from the analysis of the lateral soil in2uence. It is found that the boundary conditions of the beam are in2uenced by the soil at the left and right sides of the beam. The possible alternatives are that the soil be cut or dragged by the non-4xed ends of the beam. In the standard WP model, the lateral soil in2uence is not considered. Natural frequencies and critical load numerical values are reported for beams and piles elastically supported and for various soil parameters. The results are found with arbitrary precision depending on the number of terms taken in the series. Some unexpected modes and eigenvalues are found when the di6erent alternatives are studied. It should be noted that this special behaviour is present only when the Pasternak contribution is taken into account.