1 Shallow foundations and deep foundations
2 Spread footings and pile foundations
3 Concrete foundations and steel foundations
4 Wooden foundations and stone foundations
Answer:
1. Shallow foundations and deep foundations
1. Spread Or Open Foundation
This type of bridge foundation is suitable for moderate height, to be built on dry ground which is sufficiently firm to support the bridge structure.
It is best suited in situations where hard soil is available within 1.5 to 3 m below the bed level of watercourse and when the scouring is minimum.
2. Raft Foundation
This type of foundation is suitable for bridge when the bed of the watercourse consists of soft clay and silt and the hard soil is not available within reasonable depth (1.5 to 2.5 m) below the river bed.
It is best suited in situations where the allowable bearing capacity of the soil is low or when the bridge loads are heavy. Raft foundation is also suitable when the soil bed has some soft pockets which are compressible and there is possibility of unequal settlement.
