Learn FUNCTIONS AND TYPES OF FOUNDATIONS,foundation,types of foundation,spread foundation,pile foundation,friction pile,end bearing pile
The lowest part of a structure which transmits the weight of the structure together with live loads, seismic and wind pressure to the ground surface on which the structure rests, ensuring its safe bearing capacity, is called foundation. To increase the stability of the structure, foundations are generally placed below the ground level.
Functions of Foundations
Following are the main functions of foundations :
- To transmit and distribute the total load of the structure to a larger area of underlying support.
- To prevent differential settlement of the structure.
- To provide stability to the structure.
Types of Foundations
The following are the main types of foundations :
- Spread Foundations. The total load of the structure transmitted to the base of the structure is spread over a large area by a spread foundation. The width of the wall is constructed thicker at the base in a stepped fashion.
- Pile Foundations. A pile is a long vertical load transferring member composed of either timber, steel or concrete. In pile foundations, a number of piles are driven in the base of the structure. The piles are of two types i.e. (i) Friction pile; (ii) End bearing pile.
(i) Friction pile. The pile which supports the structure load due to friction between the pile and surrounding soil, is known as friction pile.
(ii) End bearing pile. The pile whose lower end rests on a hard rock, is called end bearing pile.
The top of various piles are connected by reinforced beams, to distribute the load uniformely to the under-lying soil.
Pile foundations are specially suitable in water-logged areas or in compressible soil or on steep slopes.
- Pier foundations. In this type of foundation, hollow vertical shafts are sunk up to the hard bed. Hollow junrtions are then filled up with inert material such as sand or lean concrete.
Pier foundations are specially suitable for heavy structure such as flyovers in sandy soil or soft soil overlying hard bed at reasonable depth.