Raft foundation is a thick concrete slab resting on a large area reinforced with steel in support with columns or walls and transfer loads from the structure to the soil. Mat foundation is spread over the entire area of the structure.
Raft foundation is generally used to support structures like residential or commercial buildings where soil condition is very poor also it generally used for storage tanks, silos, foundations for heavy industrial equipment.
Working Principle of Raft Foundation
To get a better idea of when to use the base of the raft, it is important to understand how the base of the raft works. Let’s quickly review its operating principle.
The base of the raft transmits the total load of the building to the entire area of the ground floor. The tension distribution mechanism of the balsa foundation is very simple. The total weight of the structure and the own weight of the mat are calculated and divided by the total area of the base that covers to calculate the tension in the ground.
As in the case of pond foundations, the contact area of the foundations with the ground is much more than any other type of foundations, so the load is distributed over a larger area and, therefore, the tension in the floor is smaller and the possibility of cutting failure of the floor also reduced.
When to Choose Raft Foundation ?
The design of the foundation is one of the most important structures that should be the right type of foundation. The foundation of the pond can be built if the soil has a low load capacity, the load of the structure must be distributed over a large area, the individual foundation area or any other will cover approximately 50% of the total area of the land below, the structure, the columns or the walls are placed so close that the individual bases overlap, the stress in the soil must be reduced, there is the possibility of a differential settlement in case the individual base is used, when the soil strata are unpredictable and contain compressible floor bags, the basement must be built, any other type of foot can not be used advantageously.
Written By : Mr. Parag Kamlakar Pal
B.E (Civil Engineer), NICMAR (Advance construction management) GOA