Beam and Slab Raft Foundation

Raft Foundations – Types and Advantages

Raft foundation is a thick reinforced concrete slab which spreads over a large area of soil and provides support for several columns and load bearing walls. It is also called as mat foundation which are widely used foundation system.

Types of Raft Foundation

Following are different types of raft foundations,

1. Flat Plate Type Raft Foundation
2. Thickened Flat plate Type Raft Foundation
3. Beam and Slab Type Raft Foundation
4. Piled Raft Foundation
5. Cellular Raft Foundation

1. Flat Plate Type Raft Foundation

Flat plate type raft foundations consists a reinforced concrete slab of uniform thickness covering the whole bearing area. This is suitable when the columns are placed with uniform space between them and carrying equal and small loads.

Reinforcement in slab is provided in both directions in the form of steel mesh. Two mesh are reinforced at top and bottom of the slab to balance upward and downward bending forces. Maximum thickness of 300 mm is provided for concrete slab in case of raft foundation