Pile foundations are used when the soil cannot support building loads. Piles transmit loads directly to stronger soil or bedrock below. Piles can be made of steel, concrete, or timber. They function to transmit foundation loads vertically and resist lateral and uplift loads. Concrete piles are commonly 10-20 meters long and support 300-3000 kilonewtons. Pile foundations can be end bearing piles that extend to bedrock, or friction piles driven through soft soil to a specified depth without reaching bedrock. Pile caps are reinforced with steel to resist tensile and shear stresses from heavy point loads.
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Gulam 56
1. Parul Institute of Engineering & Technology
Subject Code : 355002
Name Of Subject : STRUCTURE
Name of Unit : TYPES OF FOUNDATION
Topic : PILE FOUNDATION
Name of Faculty : SHONAK PUROHIT
Name of Students: (i) MANSURI GULAMNABI F.
En no-116380350056
2.
3. Foundations
• Foundations are structural components used to support
columns and transfer loads to the underlying Soil.
Foundations
Deep
Shallow
Isolated
footing
Combined Strap wall
footing
footing footing
Raft
footing
Caissons
Piles
4. Pile foundation
• Our building is rested on a weak soil formation
which can’t resist the loads coming from our
proposed building, so we have to choose pile
foundation.
Pile cap
Weak soil
Bearing stratum
Piles
6. Function of piles
• As with other types of foundation, the purpose
of a pile foundation is:
– To transmit a foundation load to a solid ground
– To resist vertical, lateral and uplift load
• Piles can be
–
–
–
–
Timber
Concrete
Steel
Composite
7. Concrete piles
General facts
– Usual length: 10m-20m
– Usual load: 300kN-3000kN
Advantages
– Corrosion resistance
– Can be easily combined with a concrete superstructure
Disadvantages
– Difficult to achieve proper cutoff
– Difficult to transport
8. Pile foundation
Piles can be divided in to two major categories:
1.
End Bearing Piles
If the soil-boring records presence
of bedrock at the site within a reasonable depth,
piles can be extended to the
rock surface
2.
Friction Piles
When no layer of rock is present depth at a site, point bearing piles become very
long and uneconomical. In this type of subsoil, piles are driven through
the softer material to specified depths.
9. Pile Cap Reinforcement
• Pile caps carrying very heavy point loads tend to produce high
tensile stresses at the pile cap.
• Reinforcement is thus designed to provide:
– Resistance to tensile bending forces in the bottom of
the cap
– Resistance to vertical shear
10. How does a pile look like?
•
Before presenting the actual picture of a pile foundation
some schematic pictures of pile foundation are
presented below.
11. Figure 1
All the above schematics show the various types of pile foundations and
loads carried by them