It is common to use mat foundation or deep basements to transfer the column loads to the underlying soil as well as provide floor slab for the basement.
Mat foundation construction process.
To begin constructing the solid slab raft foundation the vegetative top soil original soil is removed then the soil left behind is compressed.
Raft or mat foundations a raft foundation also called a mat foundation is essentially a continuous slab resting on the soil that extends over the entire footprint of the building thereby supporting the building and transferring its weight to the ground.
At those places we use mat foundations to distributes the whole loads of the structure to the soil when the area of the footing was increase than the soil load bearing capacity will also increase because this foundation reduces the stress on the soil at the same place.
Commonly used type of raft is the solid slab raft without downstand beam.
Raft foundation is also known as mat foundation.
Raft mat foundation is used in those places where we have less bearing capacity of the soil.
A mat foundation is used when the subsoil is weak and column loads are so heavy that the conventional spread footings cover more than 50 of the building area.