The spring method for embedded foundations

• Published in: Nuclear engineering and design Vol. 48; no. 2; pp. 377 - 392
• Main Authors: Kausel, Eduardo, Whitman, Robert V., Morray, Joseph P., Elsabee, Farid
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.01.1978
• ISSN: 0029-5493; 1872-759X
• DOI: 10.1016/0029-5493(78)90085-7

The paper presents simplified rules to account for embedment and soil layering in the soil-structure interaction problem, to be used in dynamic analyses. The relationship between the spring method, and a direct solution (in which both soil and structure are modeled with finite elements and linear members) is first presented. It is shown that for consistency of the results obtained with the two solution methods, the spring method should be performed in three steps. The first two steps require, in general, finite element methods, which would make the procedure unattractive. It is shown, however, that good approximations can be obtained, on the basis of one-dimensional wave propagation theory for the solution of step 1, and correction factors modifying for embedment the corresponding springs of a surface footing on a layered stratum, for the solution of step 2. Use of these rules not only provides remarkable agreement with the results obtained from a full finite element analysis, but results in substantial savings of computer execution and storage requirements. This frees the engineer to perform extensive studies, varying the input properties over a wide range to account for uncertainties, in particular with respect to the soil properties.