Monday 16 January 2017

Types of Foundation ?

                                                    
                                                          TYPES OF Foundations

Foundtion is the part of the building which comes directly contac to groung, it transfeer the load of struccture  to the soil. It provides the level surface for the structure. It prevent the diffential settlement of structure.

Types of foundation depends upon the type of structure and type of soil under the structure.

foundation is devided in two parts:-
(A). SHALLOW OR OPEN FOUNDATION :- A foundation is said to be shallow if Depth of foundatyion is equale to or less then width of foundation. there are Seven types of shallow foundation.

(1). Wall footing:- These are used for light structures. the width of base of concrete is at least equal to Twice of width of wall. The depth of concreat bed is atlest kept equal to projection and projection is generally kept 15cm.

(2). Isolated or Column foundation:- They are used to support individual column Generally 15cm offset is provided on all sides of concreat.They may be either stepped type or have projection in concreat.

(3). Combined footing:- These type of footing supports two or more column. Generally they are constucted by concrete. if column carry equale loads footing may be rectanguler in shape Or can be trapezoidal if footing carry unequal loads

(4). Inverted Arch foundation :- This types of structures are used on soft soil to reduce the depth of foundation. Loads above an opening are transmitted from supporting walls through inverted arches to the soil.

(5). Continuous Footings :- A single RCC slab is provided as foundation for two or three or more columns.

(6). Strap or cantilever footings :- these footing are combination of two or more individual footings. these are used at a place where distance between columns is so more.

(7). Grillarge footings:- These footings are used to transmit the heavy loads from steel column to saoil having low bearing capacity. It is made up of rolled steel joists known as grillage beams provided in single or double tiers.

(B). RAFT FOUNDATION :- A or Mat is combined footing that covers the entire area of structure. when structural loads are heavy use of these footings covers more then half of the building area. These rafts may go large settlement without cause harmful differential settlement. When Hard soil is not available to 1.5 to 2.5 mtr these footing are used..

(C). DEEP FOUNDATIONS :- These are used for soils have low bearing capacity. These foundations are in general used as basement, cylinders, shafts and piles.

(1). PILE FOUNDATION :- Pile foundation is a construction supported on piles. Piles may be composed of Timber, concreat or steel, or combination of them.They may be INSITU or PRECAST.

Types of piles :-
1. Bearing piles
2. Frictional piles
3. Screw Piles
4. compaction piles.
  




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