1. MATERIALS AND CONSTRUCTION I
FOUNDATION
SOFIA SEBASTIAN

2. FOUNDATION
Function – To transfer the structural loads from the building to the ground
Wood framed house – foundation reaches through the topsoil to the underlying soil
Masonry, steel or concrete building – foundation to the strong soil or rock
Requirements of the foundation
Safe against a structural failure (carry the weight of the building)
Must not settle

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Settlement in foundation
Settlement is the gradual sinking of a structure as the soil below its foundation consolidates after loading.
On dense, granular soils, such as coarse sand and gravel, this consolidation is usually slight and occurs quickly as loads are applied.
When the foundation soil is a moist, cohesive clay, which has a relatively large percentage of voids, consolidation can be quite large and occur slowly over a longer period of time.
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Differential Settlement in foundation
Differential settlement is the relative movement of different parts of a structure caused by uneven consolidation of the foundation soil.
This can cause a building for cracks to occur in its foundation, structure, or finishes.
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5. Classifying earth materials
ROCK – continuous mass of solid mineral material
strongest material for foundation
eg. granite, limestone – removed by drilling and blasting
SOIL
Soil is a general term referring to any earth material
too large to lift by hand or requires two hands to lift - boulder

6. whole hand to lift a particle - cobble
lifted easily between thumb and forefinger – gravel
>4.75mm
soil particles can be seen but are too small to be picked up individually - sand
(4.75– mm)
gravel
Silt particles - Too small to be seen with the unaided eye
0.075–0.005 mm
Clay particles are plate-shaped
Less than mm

7. EXCAVATION
Soldier beams and lagging as seen in horizontal section

8. THREE TYPES OF SHEET PILING
Timber sheet piling
Steel sheet piling
Precast concrete sheet piling

9. FOUNDATIONS a building consists of three major parts:
Superstructure, substructure, and
foundation. The substructure in
this example contains two levels of
basements, and the foundation consists of bell caissons.
a building consists of three major parts:
the superstructure, which is the above ground portion of the building;
the substructure, which is the habitable
below-ground portion;
and the foundations,

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Types of Foundation
Foundations
Shallow
Column footing
Strip foundation
Raft foundation
Deep
Pile foundation
Caisson foundation
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11. Shallow foundations -transfer the
Strip footing/
Wall footing
Combined footing
Column footing/
Pad foundation
Shallow foundations -transfer the
load to the earth at the base of the column or wall of the substructure.
Mat foundation/ Raft foundation

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Types of Shallow Foundation
Concrete strip foundation
Used for load bearing masonry structure
Consist of continuous mass concrete strips poured in the bottom of trenches
This concrete strip is of uniform width and depth
Depending on soil depth – the maximum depth – 90cm
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Column/ Pad/ Isolated foundation
To support concrete columns
Square concrete pad foundation distributes the load evenly on the ground
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Raft/ Mat foundation
The over-site concrete slab becomes the raft foundation
Slab can be thickened at the edges with an edge beam and thickened underneath internal load bearing walls
Mesh reinforcement increases the strength of the raft foundation and distributes the pressures of the building loads evenly
For soil which has poor bearing capacity
When the building loads are quite small and the cost of digging separate foundation is eliminated
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15. Deep foundations piles (15 cm diameter) or
caissons (45 cm -90 cm diameter),
penetrate through upper layers of
incompetent soil in order to transfer
the load to good bearing soil or
rock deeper within the earth.

16. Caisson, or drilled pier
Caissons are concrete cylinders poured into drilled holes.
They reach through weaker soil (light shading) to bear on competent soil beneath.
end bearing caisson is belled when additional bearing capacity is required.
socketed caisson is drilled into a hard stratum and transfers its load
weaker soil
stronger soil

17. If it is driven only into softer material and a good frictional resistance between the which it is driven; in this case, it is known as a friction pile.
PILE
- forcibly driven into the earth rather than drilled and poured.
For non cohesive soils,
subsurface water conditions, or
excessive depth of bearing strata
Timber pile
a tree trunk with its branches and bark removed beaten into the earth with repeated blows of a heavy mechanical hammer.
If a pile is driven until its tip encounters firm resistance from a suitable load bearing stratum such as rock, dense sands, or gravels, it is an end bearing pile.

18. PILE FOUNDATION
Piles are usually driven closely together in clusters of piles each.
The piles in each cluster are later joined at the top by a reinforced concrete pile cap
The pile cap distributes the load of the column or wall above among the piles
An elevation view of a pile cap, column,
and floor slab.

19. Pile Materials
Piles may be made of timber, steel,
concrete, and various combinations
of these materials
Timber piles
they are economical for lightly
loaded foundations.
they cannot be joined during
driving and are, therefore, limited
to the length of available tree trunks

20. Steel piles Two forms of steel piles are used, H-piles and pipe piles.
H-piles are special hot-rolled, wide-flange sections, 20 to 35 cm deep
any convenient lengths
Minipiles, also called pin piles or micropiles, are a lightweight form of steel piles made from steel bar or pipe 5 to 30 cm in diameter.
Steel pipe piles have diameters of
20 to 40 cm

21. concrete piles - precast or site cast
Precast concrete piles are square, octagonal,
or round in section
reinforced
Advantages
high load capacity, an absence of corrosion or decay problems,
A site cast concrete pile is made by driving a hollow steel shell into the ground and filling it with concrete.

22. Retaining wall
holds soil back to create an abrupt change in the elevation of the ground.
must resist the pressure of the earth that bears against it on the uphill side.

23. Retaining wall
Retaining walls may be made of masonry, preservative-treated wood,
coated or galvanized steel, precast
concrete, or, most commonly, sitecast
concrete.