Foundations are the sub-structure which transfers the load of the super-structure to the soil below the foundation. To transfer the load effectively to the soil, it is important to understand the properties and the strength of the soil below the structure. If the soil is of the sufficient strength then it will be safe to construct the foundation on it. In case the soil is lose on the top surface then either we have to construct the foundation accordingly or we have to dig the soil to reach the hard strata.
Now the foundations on the basis of their depth from the ground level can be broadly classified into two types:
(1) Shallow foundation (2) Deep foundation
Shallow foundations are the foundations which has their depth(D) either less than or equal to the breadth(B) of the foundation. Shallow foundations are generally constructed on the higher strength soils. They are further classified into the following types:
(a) Spread footing (b)Strip footing (c) Strap foundation (d) Combined footing.(d) Raft or mat foundation
Spread footing is constructed by spreading out the base of the column to higher width and length.
Strip footing is the foundation provided to the load bearing walls. They have small width and length a little more than the length of the wall.
Strap footing is constructed by joining the two footings with a strap. Combined footing is constructed by joining two or more than two columns, together with a single combined footing.
Raft or mat foundation is provided when the area of the spread footings of the individual columns increases the 50% of the total area of the base. It is considered more economical.
Deep foundations are the foundations where the depth is more than the width of the foundation. These are constructed when the soil is of the insufficient length on top, so there is a need to reach the hard strata at the greater depth or to transfer the load to a larger area.
They are further classified into three types:
(a) Pile foundations (b) Well foundation (c) Caisson
Now the foundations on the basis of their depth from the ground level can be broadly classified into two types:
(1) Shallow foundation (2) Deep foundation
Shallow foundations are the foundations which has their depth(D) either less than or equal to the breadth(B) of the foundation. Shallow foundations are generally constructed on the higher strength soils. They are further classified into the following types:
(a) Spread footing (b)Strip footing (c) Strap foundation (d) Combined footing.(d) Raft or mat foundation
Spread footing is constructed by spreading out the base of the column to higher width and length.
Strip footing is the foundation provided to the load bearing walls. They have small width and length a little more than the length of the wall.
Strap footing is constructed by joining the two footings with a strap. Combined footing is constructed by joining two or more than two columns, together with a single combined footing.
Raft or mat foundation is provided when the area of the spread footings of the individual columns increases the 50% of the total area of the base. It is considered more economical.
Deep foundations are the foundations where the depth is more than the width of the foundation. These are constructed when the soil is of the insufficient length on top, so there is a need to reach the hard strata at the greater depth or to transfer the load to a larger area.
They are further classified into three types:
(a) Pile foundations (b) Well foundation (c) Caisson
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