Strip foundations consist of a continuous longitudinal strip of concrete or masonry, which provide a firm and level base on which the walls can be built. These are used where the building loads are carried by entire walls rather than isolated columns, such as in older buildings made of masonry.
Combined footing is constructed when two or more columns are close enough and their isolated footings overlap each other. It is more economical and is easier to construct. The thickness of the concrete should be at least equal to the projection of the strip each side of the column.
Raft Foundations, also called Mat Foundations, are most often used when basements are to be constructed. These types of foundations are suitable when the bearing capacity of the soil is low, but the soil should be such that it can be properly & easily compacted and levelled.
Pile foundation is a type of deep foundation which is used to transfer heavy loads from the structure to a hard rock strata much deep below the ground level. Pile foundations are capable of taking higher loads than spread footings. This is also used to prevent uplift of structure due to lateral loads such as earthquake and wind forces.