Transcript of Foundation Engineering CE 483 3. Types of foundation & foundation materials Copy right reserved to...
- Slide 1
- Foundation Engineering CE 483 3. Types of foundation &
foundation materials Copy right reserved to Dr O. Hamza
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- Contents Introduction Shallow Foundations Deep Foundations CE
483 - Foundation Engineering - 3. Types of Foundations 2 Copy right
reserved to Dr O. Hamza
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- Introduction CE 483 - Foundation Engineering - 3. Types of
Foundations 3 Why different types of foundations? General types of
foundations
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- Why different types of foundations? CE 483 - Foundation
Engineering - 3. Types of Foundations 4 What type of foundation you
choose will depend upon many factors: Structure: type, use,
loadings, code requirement. Ground: layers, subsurface soil
condition, groundwater. Cost Introduction
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- 5 Foundation might be: Shallow, or Deep They could be
constructed from: Concert (reinforced) Steel Other materials:
Timber, Stones, General types of foundations Shallow foundations
(footings) Deep foundation (piles) High building Low-rise building
supported by
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- Shallow foundations CE 483 - Foundation Engineering - 3. Types
of Foundations 6 Definition Advantages Types of shallow
foundations
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- Shallow foundations 7 Definition CE 483 - Foundation
Engineering - 3. Types of Foundations Shallow foundations are those
founded near to the finished ground surface; generally where the
founding depth (D f ) is less than the width of the footing (B) and
generally less than 3m. Shallows foundations are used when surface
soils are sufficiently strong and stiff to support the imposed
loads. They are generally unsuitable in weak or highly compressible
soils, such as poorly-compacted fill, peat, and alluvial deposits,
etc. DfDf B
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- Shallow foundations 8 Advantages CE 483 - Foundation
Engineering - 3. Types of Foundations Cost (affordable)
Construction procedures (simple) Material (mostly reinforced
concrete) Labor (doesnt need high experience)
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- Shallow foundations 9 Types of shallow foundations CE 483 -
Foundation Engineering - 3. Types of Foundations Shallow Foundation
Spread Combined Mat (Raft) 1 2 3
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- Shallow foundations 10 Types of shallow foundations CE 483 -
Foundation Engineering - 3. Types of Foundations Shallow Foundation
Spread Combined Mat (Raft) 1 2 3 often rectangular or square and
are used to support single columns. This is one of the most
economical types of footings and is used when columns are spaced at
relatively long distances. Column Pad footing Pad foundations Strip
foundation
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- Shallow foundations 11 Types of shallow foundations CE 483 -
Foundation Engineering - 3. Types of Foundations Shallow Foundation
Spread Combined Mat (Raft) 1 2 3 Pad foundations Strip foundation
Strip footings are continuous foundation used to support walls.
Strip, continuous, or wall footing Wall
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- Shallow foundations 12 Types of shallow foundations CE 483 -
Foundation Engineering - 3. Types of Foundations Shallow Foundation
Spread Combined Mat (Raft) 1 2 3 Rectangular Trapezoidal combined
footing Strap footing Column Footing Plan view Cross section
Combined footings are used when two columns are so close that
single footings cannot be used or when one column is located at or
near a property.
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- Shallow foundations 13 Types of shallow foundations CE 483 -
Foundation Engineering - 3. Types of Foundations Shallow Foundation
Spread Combined Mat (Raft) 1 2 3 Rectangular Trapezoidal Column
View plan of Trapezoidal combined Footing
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- Shallow foundations 14 Types of shallow foundations CE 483 -
Foundation Engineering - 3. Types of Foundations Shallow Foundation
Spread Combined Mat (Raft) 1 2 3 Rectangular Trapezoidal Strap
Consist of two single footings connected with a beam or a strap and
support two single columns. This type replaces other combined
footings and is more economical. Column Footing Plan view Cross
section Column Footing Strap Strap beam
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- Shallow foundations 15 Types of shallow foundations CE 483 -
Foundation Engineering - 3. Types of Foundations Shallow Foundation
Spread Combined Mat (Raft) 1 2 3 Consists of one slab usually
placed under the entire building area. Column Footing Plan view
Cross section
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- Shallow foundations 16 Types of shallow foundations CE 483 -
Foundation Engineering - 3. Types of Foundations Shallow Foundation
Spread Combined Mat (Raft) 1 2 3 Raft foundations are used, when
soil bearing capacity is low, column loads are heavy, single
footings cannot be used, piles are not used, and differential
settlement must be reduced. Steel reinforcement for the raft
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- Shallow foundations 17 Types of shallow foundations CE 483 -
Foundation Engineering - 3. Types of Foundations Shallow Foundation
Spread Combined Mat (Raft) 1 2 3 A raft foundation normally
consists of a concrete slab which extends over the entire loaded
area. It may be stiffened by ribs or beams incorporated into the
foundation. Soft soil Raft Beam
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- Deep foundations CE 483 - Foundation Engineering - 3. Types of
Foundations 18 Definition Types of deep foundations
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- Deep foundations 19 Deep foundations are those founding too
deeply below the finished ground surface for their base bearing
capacity to be affected by surface conditions, this is usually at
depths >3 m below finished ground level. Deep foundations are
used when there are weak soils near the surface or when loads are
very high, such as very large skyscrapers. Deep foundations derive
their support from deeper soils or bedrock. Definition High
building CE 483 - Foundation Engineering - 3. Types of Foundations
Bedrock Soft soil
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- Deep foundations 20 Types of deep foundations CE 483 -
Foundation Engineering - 3. Types of Foundations Deep Foundation
Piles Piers Caissons Compensated foundations 1 3 4 2
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- Deep foundations 21 Types of deep foundations CE 483 -
Foundation Engineering - 3. Types of Foundations Deep Foundation
Piles Piers Caissons Compensated foundations 1 3 4 2 Piles are
relatively long, slender members that transmit foundation loads
through soil strata of low bearing capacity to deeper soil or rock
strata having a high bearing capacity. Piles used as a foundation
for structure
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- Deep foundations 22 Types of deep foundations CE 483 -
Foundation Engineering - 3. Types of Foundations Deep Foundation
Piles Piers Caissons Compensated foundations 1 3 4 2 In addition to
supporting structures, piles are also used to anchor structures
against uplift forces and also to assist structures in resisting
lateral and overturning forces. Piles used as a retaining wall
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- Deep foundations 23 Types of deep foundations CE 483 -
Foundation Engineering - 3. Types of Foundations Deep Foundation
Piles Piers Caissons Compensated foundations 1 3 4 2 Pile caps are
thick slabs used to tie a group of piles together to support and
transmit column loads to the piles. Piles Plan Pile Cap Cross
section Column
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- Deep foundations 24 Types of deep foundations CE 483 -
Foundation Engineering - 3. Types of Foundations Deep Foundation
Piles Piers Caissons Compensated foundations 1 3 4 2 Pile length
and size have to be designed to tolerate all possible loading
conditions. Column Broken Piles
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- Deep foundations 25 Types of deep foundations CE 483 -
Foundation Engineering - 3. Types of Foundations Deep Foundation
Piles Piers Caissons Compensated foundations 1 3 4 2 Pile length
and size should be designed to tolerate all possible loading
conditions. Column Broken Piles Shanghai building collapse
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- Deep foundations 26 Types of deep foundations CE 483 -
Foundation Engineering - 3. Types of Foundations Deep Foundation
Piles Piers Caissons Compensated foundations 1 3 4 2 Based on
method of installation: Driven piles (displacement piles): made of
steel, pre-stressed concrete, timber, or composite. Bored piles
(replacement piles): Augured and cast in-situ. Other piles:
Sheet-pile, Micropiles, Suction Piles, Vibrated Stone Columns
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- Deep foundations 27 Types of deep foundations CE 483 -
Foundation Engineering - 3. Types of Foundations Deep Foundation
Piles Piers Caissons Compensated foundations 1 3 4 2 Board piles
Driven piles Driven Piles
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- Deep foundations 28 Types of deep foundations Deep Foundation
Piles Piers Caissons Compensated foundations 1 3 4 2 Driven or
displacement piles
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- Deep foundations 29 Types of deep foundations CE 483 -
Foundation Engineering - 3. Types of Foundations Deep Foundation
Piles Piers Caissons Compensated foundations 1 3 4 2 Pile length
and size have to be designed to tolerate all possible loading
conditions. Bored piles
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- Deep foundations 30 Types of deep foundations Deep Foundation
Piles Piers Caissons Compensated foundations 1 3 4 2 Bored or
replacement piles -length can be varied, very long lengths possible
-removed soil can be compared with design data -penetration tests
can be carried out in boreholes -very large bases can be possibly
formed -drilling tools can break up boulders, obstructions,..
-little noise and vibration during construction -no ground heave
Advantages: -piles liable to squeezing and necking in soft soil
-special techniques required for concreting in water bearing ground
-concrete cannot be inspected after installation -enlarged bases
cannot be formed in collapseable soil -cannot be easily extended
above ground -boring may cause instability and settlement of
adjacent structures Disadvantages:
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- Deep foundations 31 Types of deep foundations CE 483 -
Foundation Engineering - 3. Types of Foundations Deep Foundation
Piles Piers Caissons Compensated foundations 1 3 4 2 Piers are
foundations for carrying a heavy structural load which is
constructed in-situ in a deep excavation.
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- Deep foundations 32 Types of deep foundations CE 483 -
Foundation Engineering - 3. Types of Foundations Deep Foundation
Piles Piers Caissons Compensated foundations 1 3 4 2 Caissons are a
form of deep foundation which are constructed underwater above
seabed, then sunk to the required level by excavating or dredging
material from within the caisson.
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- Deep foundations 33 Types of deep foundations CE 483 -
Foundation Engineering - 3. Types of Foundations Deep Foundation
Piles Piers Caissons Compensated foundations 1 3 4 2 These are deep
foundations in which the relief of stress due to excavation is
approximately balanced by the applied stress due to the foundation.
Original Site Soft soil susceptible to settlement or low bearing
strength Remove soil equal in weight to the building Soil pressure
at this level is no greater than when original soil was in place
The net stress applied is therefore very small. A compensated
foundation normally comprises a deep basement.
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- Reference s 34 Braja M Das, 2011, Principles of Foundation
Engineering,, 7th ed. Previous course materials at KSU
http://www.slideshare.net/stootypal/types-of-foundation
http://data.bolton.ac.uk/staff/phm2/files/Semester1/J3%20PJ4%20Geotechnic
s/Pile%20Foundations%20v1.00%20Oct2010.pdf
http://data.bolton.ac.uk/staff/phm2/files/Semester1/J3%20PJ4%20Geotechnic
s/Pile%20Foundations%20v1.00%20Oct2010.pdf Geotechnical on the web:
http://environment.uwe.ac.uk/geocal/foundations/founbear.htm.
http://environment.uwe.ac.uk/geocal/foundations/founbear.htm CE 483
- Foundation Engineering - 3. Types of Foundations