# Exact Analysis of Raft Foundation Subjected to an Out-of-Plane Point Load

 International Journal of Civil Engineering © 2017 by SSRG - IJCE Journal Volume 4 Issue 7 Year of Publication : 2017 Authors : S.O. Ajayi, T.N. Johnarry, T.C. Nwofor 10.14445/23488352/IJCE-V4I7P101
##### How to Cite?

S.O. Ajayi, T.N. Johnarry, T.C. Nwofor, "Exact Analysis of Raft Foundation Subjected to an Out-of-Plane Point Load," SSRG International Journal of Civil Engineering, vol. 4,  no. 7, pp. 1-8, 2017. Crossref, https://doi.org/10.14445/23488352/IJCE-V4I7P101

##### Abstract:

Foundation rafts, in various aspects behave as plates or slabs. This study focuses on the case of surface point load for both deflection and stress convergence of series solutions.Resting on an elastic foundation, the behavior under load is influenced by the modulus of the sub-grade reaction of the soil. Several methods of analysis have been developed in the past to obtain plate solution;however, in this study, the main focus is to use a new method of analysis, “the curvaturedisplacement method”to achieve point load solution. To achieve this, the shape function for an all-round simply supported plate was adopted. This is because the slab is assumed to rest simply on heavy perimeter beams. The curvaturedisplacement method was used to obtain the equation for deflection, curvature and moment using nine series-terms where convergence error became negligible. The equations obtained were thereafter, used to estimate the result for deflection, curvature and moment for a simplified solution. These are the results needed for design of the slab. Results found were among the best in the literature and the particular case of moments at the point load giving a convergent result of 0.43P stands out.

##### Keywords:

Raft foundation, Elastic foundation, Curvature and displacement, Modulus and subgrade reaction.

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