## Foundations

Every structure has two component parts. One is called; foundation and the other super-structure. Foundation is that part of the structure which is generally constructed below the ground level. It is often confused that foundation is constructed to take up the load of the structure or to support it. Cut actually this is not the case. No doubt the structure rests over the foundation but it is not supported by the foundation. The foundation transmits the load of the structure to the sub-soil below it, never a larger area uniformly. The word foundation as applied to buildings is defined as the extended base of walls and pillars carried below the ground level, to distribute the load of the structure over a larger area of the-sub-soil.

The Foundation is the most important part of a structure. The strength and stability of the structure depends upon its foundation. If the foundation fails, the super-structure however strong it may be, cannot stand. Hence for a stable structure, a good foundation is essential.

## Layout of foundation plan

Layout of Foundation     Layout of foundation plan : After determining the width and depth of foundation, a drawing showing the width of foundations of various walls is prepared. It is known as foundation plan. To start the commencement of excavation, the centre line of one of the longest walls is just mark­ed out by stretching a string between two wooden pegs, driven at the ends. Now set out the centre lines of other walls, The reference to this wall.   The centre line perpendicular to the reference line, is marked on the ground by 3 : 4 : 5 method. Suppose AB is the refer­ence line. A line BC is to be marked as perpendicular to AB. Now set off a distance of 3 m (or three divisions of any length) on AB and take two strings of 4m and 5 m lengths, (or 4 and 5 divisions…

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## Different types of foundations, which are generally used for structures

Content of this article : Types of foundations, Spread footing foundation, Benching or stepped foundation, Pile foundation, classification of piles foundation, Piles can be classified according to material-wooden piles,concrete piles,RCC piles, sheet piles,classification is based on the mode of working of the piles,(i) Bearing pills, and (ii) Friction piles.Raft foundation,Well foundation,Cassion's foundation,cantilever foundations,combined footing foundation,Inverted arch foundation,Grillage foundation. Types of Foundations The following are the different types of foundations, which are generally used for different structures : Spread footing foundation Benching or Stepped Foundation. Pile Foundation. Raft Foundation. Well Foundation. Caisson's Foundation. Cantilever Foundation. Combined Footing Foundation. Inverted Arch Foundation. Grillage Foundation. Spread footing foundation This is the simplest type of foundation and is generally used for ordinary build­ings on alluvial soils. This type of foundation can normally be used for three to four-storied buildings on common type of alluvial soils. The spread footing  consists of a concrete base, generally…

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## Methods of Improving the Bearing Capacity of soils

Content of the article : methods of improving the bearing capacity of soils  Methods of Improving the Bearing Capacity of soils The bearing capacity of a soil mainly depends on the closeness of its particles. The bearing capacity of a soil can be increased by the following methods: By increasing the depth of foundation. The compactness of the foil increases as we go below the ground level. As the bearing capacity directly depends on the compactness of the soil, it will go on increasing as the depth of foundation is increased. By draining of the sub-soil under.  Water reduces the cohe­sive properties and hence reduces the bearing capacity of the soil. By draining off water from the sub-soil the bearing capacity of the soil is certainly increased. By compacting the soil.  If the soil is compacted thoroughly, the voids are decreased and bearing capacity is increased. By confining the soil…

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## Soils and their Bearing Capacity

Content of this article : Bearing capacity of soils,Methods of determining the Bearing Capacity of Soils,Safe Bearing Capacity.factor of safety,safe bearing capacity of different soils. Soils and their Bearing Capacity The soils on which a structure rests may be classified into three categories: (a) Hard soils. These soils are generally rocky in nature, in compressible and can bear fairly good loads. Solid rock, moo rum and stony soils are examples. (b) Soft soils. These are alluvial soils and are compressible when loaded. They can to take much load. Ordinary clay, loam, and common soils are examples of this. (c) Spreading soils. These soils are compressible when they are confined and prevented from spreading. These soils when load­ed spread out laterally. Sand and gravel are examples of this type of soil. Bearing capacity of soils. Bearing power or Bearing capa­city of a soil is defined as the maximum load that a…

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