Foundations: design load calculations

When using FEM models to check the bearing capacity, it is difficult to define the maximum load that can be applied on a foundation with given dimensions. Basically the FEM is a method in which the stress-strain behaviour of the soil is modelled as reahstically as possible. However, failure occurs if deformations become uncontrollable and this cannot be modelled with standard FEM software. In general, the dimensions and foundation level are chosen and the design load is applied. The factor of safety is then calculated by means of a 7c -reduction method (see S.4.3.7.3) until the deformations become unreahstically large due to instabihty of the system. 

The necessity of thorough comparison between blast parameter fields resulting from such different explosives is also based on an ordered foundation. The point is that the available experimental data are used for verification of theoretical models designed for calculations of blast loads resulting from deflagration/detonation of gas mixtures [21-24, 32-35]. 

The design of foundations embodies three essential operations, namely, calculating the loads to be transmitted by the foundation structure to the soils or rocks supporting it, determining the engineering performance of these soils and rocks, and then designing a suitable foundation structure. 

Anchors need not be designed for shear if it can be shown that the factored shear loads are transmitted through frictional resistance developed between the bottom of the base plate and grout at the top of the concrete foundation. If there is moment on a base plate, the moment may produce a downward load that will develop frictional resistance even if the eolumn or vertical vessel is in uplift, and this downward load ean be eonsideied in calculating frictional resistance. Care should be taken to assure that the downward load that produces frictional resistance occurs simultaneously with the shear load. 

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