Some useful construction tips for foundation design

Foundation is the most vital portion of structure. It is set up underneath plinth level up to the soil. It is directly associated with soil and passes on load of super structure to soil. Usually it is beneath the ground level. If some portion of foundation is placed over ground level, it is enclosed with earth filling. This portion of structure is not connected with air, light etc. It is the unseen part of the structure.

Depth of Foundation: Depth of foundation is affected by the following factors.

1. Availability of plenty bearing capacity
2. Depth of shrinkage and swelling toward clayey soils which is caused by seasonal changes and result in substantial movements.
3. Depth of frost penetration for fine sand and silt.
4. Opportunity for excavation around
5. Depth of ground water table
6. Practical lowest depth of foundation should not be under 50 cm. to facilitate elimination of top soil and variations in ground level.
7. So the desired depth of foundation should be from 1.00 meter to 1.5 meter from original ground level.

Footing: Footing is a structure built up with brick work, masonry or concrete beneath the base of a wall or column for dispersing the load over a broad area.

Width of Foundation/Footings: The width of footings is arranged as per the structural design. For the light loaded two storied buildings like houses, flats, school buildings etc, the width of foundation should be as follow :-

1. The width of footing should not be below 75 cm for one brick thick wall.
2. The width of footing should not be below 1 meter for one and half brick wall.

Different Processes in Foundation Work: The methods undertaken in the foundation works are as follow :-

1. Excavation of earth work in trenches for foundation.
2. Placing cement concrete.
3. Placing the footing for raft or column construction.
4. Arranging Anti termite treatment.
5. Placing Brick work up to plinth level.
6. Placing Damp resistant course on the walls.
7. Fill up of earth around the walls.
8. Fill up of earth in the building portion fit for the desired height along with plinth level.

Ref.: gharexpert.com