Shallow Foundation

Foundation is the lowest part of the building or the civil structure that is in direct contact with the soil which transfers loads from the structure to the soil safely. Generally, the foundation can be classified into two, namely shallow foundation and deep foundation.

1. PRESENTATION ON INDIVIDUAL
FOOTING

2. Definition
A foundationis a
structurethat transfers
loads to the ground.
Foundations are generally
broken into two
categories:
shallow foundation
&
deep foundation

3. Types offoundation
A shallow foundationis a type of foundationwhich
transfers building loads to the earth very near the surface,
rather than to a subsurface layer or a range of depths as
does a deep foundation.
Deep foundationsare used to transfer a load from a
structure through an upper weak layer of soil to a
stronger deeper layer of soil. Deep foundations are
distinguished from shallow foundationsby the depth they
are embedded into the ground.

4. Foundation Depth
foundation design depends on various factors, e.g.
type of building, type of construction/materials
used, ground conditions, site slope, natural
hazards etc.
designer/engineer will consider these factors when
determining the design of a buildings foundation.

5. Objectives of Foundation
1.To distribute the load of the structure on large area.
2.To distribute the load on underlying soil evenly.
3.To provide a levelled and hard surface for the super-
structure to be built over it.
4.To increase the stability as a whole against sliding,
overturningor other distribution forces like wind,
rain etc.
5.To prevent lateral movement of the supporting
materials so that safety of the structure is not
endangered.

6. Types of Shallow Foundation
Isolated/individual footing
Combined footings
Strap footing
Strip footing
Mat or raft foundation

7. Isolated footings (also known as Pad or Spread footings) are commonly used for shallow foundations in order to carry
and spread concentrated loads, caused for example by columns or pillars.
Isolated footings

8. Combined Footing

9. A strap footing is simply a combined footing with two
or more footings (under a column each) are joined
together with a beam to form a single combined
footing;
Strap Footing

10. Awallfootingorstripfootingisacontinuousstrip
ofconcretethatservestospreadtheweightof
aload-bearingwallacrossanareaofsoil.Strip
footingsarecommonlyusedasfoundationsofload-bearing
walls.
Strip Footing (Wall Footing)

11. MAT Foundation

12. MAT Foundation

16. Standard
Penetration Test
16
Fig.Standardpenetrationtest

17. Standard
Penetration Test
Thenumberofblows,Nrequiredtoproduceapenetrationof300mm(12
inches)isregardedasthepenetrationresistance.Toavoidseatingerrors,
theblowsforthefirst150mm(6inches)ofpenetrationarenottakeninto
account.
Theblowcountforthenexttwo150-mmincrementsisreportedasthe
penetrationresistance(orpenetrationcount)Nunlessthelastincrement
cannotbecompleted(blowcount>100orrockisencountered).Theboring
logshows"refusal"iftheblowcountexceeds100.Aschematicdiagramof
StandardPenetrationTestsetupisshowninFig.16.
17