The Structural Engineer > Archive > Volume 50 (1972) > Issues > Issue 4 > A Note on the Computer Analysis of Foundation Rafts Resting on Plastic Soils: a Technical Note
Name of File 3349-50-04.pdf cached at 13/12/2017 14:49:57 - with 4 pages. pdfPath: E:\k9.istructe.org\CMS\webtest\files\39\399c4afe-adb4-4790-9b58-3c3c5491674b.pdf. thumbPath: E:\k9.istructe.org\CMS\webtest\files\pdfthumbs\399c4afe-adb4-4790-9b58-3c3c5491674b_1.png. objDoc: 1 - True. objPreview.Log: . strFileName: 399c4afe-adb4-4790-9b58-3c3c5491674b_1.png

Members/subscribers must be logged in to view this article

A Note on the Computer Analysis of Foundation Rafts Resting on Plastic Soils: a Technical Note

The paper discusses the problem of design of rafts resting on soft subgrades in which long-term deformations lead to a redistribution of reactions. Design moments and shears are calculated by assuming a uniform upthrust, and it is usual to analyse an inverted raft on column supports subjected to a uniformly distributed loading. Errors inherent in such an approach are discussed and an alternative method is suggested. This assumes an elastic subgrade composed of very soft springs giving prominence to raft stiffness and ensuring uniform distribution upthrust. The method automatically satisfies local and overall equilibrium. A comparison of the two approaches on a raft analysed by the author for consulting engineers demonstrates the differences in design moments predicted by the two methods. F. Sawko