Prediction of Ng Values and Settlement for Square Footings
M. S. Dixit
Research Scholar, Department of Civil Engineering, Government College of Engineering, Aurangabad (Maharashtra State), India, 431 005
K. A. Patil
Associate professor, Department of Civil Engineering, Government College of Engineering, Aurangabad (Maharashtra State), India, 431 005
Foundation is the important part of any structure and which bears the load coming from the superstructure. While designing any foundation it is necessary to know the type of soil, its behavior and bearing capacity. The conventional method of design of footing requires sufficient safety against failure and the settlement must be kept within the allowable limit. These requirements are dependent on the bearing capacity of soil. Thus, the estimation of load carrying capacity of footing is the most important step in the design of foundation. The number of theoretical approaches, in-situ tests and laboratory model tests are available to find out the bearing capacity of footing. The reliability of any theory can be demonstrated by comparing them with the experimental results. The results from laboratory model tests on square footings resting on sand are presented. The effect of bearing capacity of sand below the footing for square plate with variation in size, depth and the effect of permissible settlement is evaluated. A steel tank of size 900mm◊1200mm◊1000mm is used for conducting model tests. Bearing capacity factor Ng is evaluated and is compared with Terzaghi, Meyerhof, Hansen and Vesicís Ng values. From the experimental investigations it is found that, as the depth of sand cushion below the footing (Dsc) increases, ultimate bearing capacity and settlement values increases.
Keywords: Square footing, model test, sand, depth, ultimate bearing capacity, settlement.
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