1. Pad or column footings ( Isolated or Combined )
used to support single columns. This is one of the most economical types of footings and is used when columns are spaced at relatively long distances
usually support two columns, or three columns not in a row. Combined footings are used when tow columns are so close that single footings cannot be used or when one column is located at or near a property
2. Cantilever or strap footings
consist of two single footings connected with a beam or a strap and support two single columns. This type replaces a combined footing and is more economical.
3. Continuous footings
support a row of three or more columns. They have limited width and continue under all columns.
4. Wall Footings
are used to support structural walls that carry loads for other floors or to support nonstructural walls.
5. Mat (Raft) footings (Thickened slabs)
consists of one footing usually placed under the entire building area. They are used, when soil bearing capacity is low, column loads are heavy single footings cannot be used, piles are not used and differential settlement must be reduced.
Raft foundations are used to spread the load from a structure over a large area, normally the entire area of the structure. They are used when column loads or other structural loads are close together and individual pad foundations would interact.
A raft foundation normally consists of a concrete slab which extends over the entire loaded area. It may be stiffened by ribs or beams incorporated into the foundation.
Raft foundations have the advantage of reducing differential settlements as the concrete slab resists differential movements between loading positions. They are often needed on soft or loose soils with low bearing capacity as they can spread the loads over a larger area.
2- Deep Foundations-