[01] Zainal Abdul Kareem E., Civil Engineering Department, University of Baghdad, Engineering College, Baghdad, Iraq. [02] Amjad Ibraheem Fadhil, Civil Engineering Department, University of Baghdad, Engineering College, Uruk University, Baghdad, Iraq.

Bearing capacity prediction of shallow foundations is of great importance in shallow foundation design process. Many proposed and implemented methods have been used in this field of soil mechanics for many years and became a standard procedure for these calculations. This work proposes a new method with alternative and simpler approach to predict the ultimate bearing capacity of sandy soil suitable for shallow foundation using strip footing based on the soil surface, which can be further extended for other shapes of shallow foundations, under soil surface, or other types of soils (i.e. c–∅) soils. This approach is based on specifying the shape of the failure surface under shallow foundation which is located and defined by a new equation that may describe this surface instead of the multi–relations (i.e. log–spiral curve and a linear relationship proposed by Terzaghi, 1943 [1] and others).This proposed equation is to cover many internal friction angles (∅) for sand, ranging from 10º to 50º and normalized for footing width (B); besides being more general and can be directly implemented for this range of internal friction angles of ∅. Bearing capacity calculation results were found in good agreement with the results obtained from Terzaghi’s equation, Meyerhof’s [2], and solution based on Rankine wedges method, Lamb 1979 [3], though the values of equivalent N_γ were found more conservative but more realistic and agree with some bearing capacity design codes.

Shallow Foundation, Bearing Capacity, Failure Surface, Strip Footing

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