TOPIC 2: TYPES OF FOUNDATION
WEEK 3
FACTORS AFFECTING FOUNDATION
SELECTION
TYPE OF SHALLOW FOUNDATION
TYPE OF PILES AND CAPACITY.
ADVANTAGES AND LIMITATIONS
Learning Outcomes
Student should be able to:
• Discuss criterias for foundation
selection(CO2-PO10)
• Determine type of foundation(CO2-PO10)
FUNCTION OF A FOUNDATION
• To transmit load to the ground without
bearing capacity failure and excessive
settlement.
Bearing Pressure and Bearing Capacity
Concept
Factors Affecting Foundation Selection
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Subsurface condition
Type and magnitude of loading
Type of structure
Constraint – vibration, noise
Cost
Time
Logistic
• Shallow Foundation
- pad footing, strip footing, raft foundation
Not more than 3m. A basement though may used shallow
foundation if the ground is adequate.
Deep Foundation
Cast in situ pile, driven or jack in pile.
Deep Foundation
FUNCTION OF PILES
Transmit load to deeper depth underneath the structure
when upper layer of soil too weak to support the load.
Resist horizontal force by bending.
Anchor a structure subjected to uplifting.
Hold a structure where the base is subjected to erosion.
PILE
CLASSIFICATION
Pile classification based on materials
- concrete piles – 150RC square pile structural capacity
250kN, 400x400 – 1980kN
- Spun pile – 250mm diameter 460kN, 800mm diameter
3450kN
- timber piles- 100kN
bakau pile – 10kN, For Sustainability, Government
Projects not allowed to use bakau pile.
- steel pile
- composite piles
Pile classification based on installation
- Displacement piles : Driven piles, jacked piles
Non displacement piles : Bored pile, micropiles
• Advantages and limitations of certain type
of piles
Cost, availability, capacity, suitability for the
ground strata, noise, vibration,
machineries and rigs.
Pile classification based on functions
- compression piles
- tension piles
- batter/rake piles – resist lateral load. Max inclination 4:1
Pile classification based on bearing
- end bearing piles
- friction piles
- partly end bearing and partly friction
RAFT FOUNDATION
Covers the entire area under the structure, supporting several
columns and walls
For low bearing capacity
Pockets of loose soil
Or when individual spread footing covers more than 50% area.
TYPES OF RAFT FOUNDATION
Bearing Capacity of Raft
Foundation
Case study: Foundation of KL Tower
Floating Foundation
Concept
Usage
Method of Construction
Water Proofing
Basement Construction
Cut and fill method
Secant Pile Wall
Diaphragm Wall