EGB273 Exam UPDATED ACTUAL
QUESTIONS AND CORRECT ANSWERS
What are the functions of foundation for a building structure? - CORRECT ANSWER •
Support imposed loads
• Prevent settlement (including differential settlement)
• Prevent possible movement of structure due to periodic shrinkage and swelling of subsoil
• Allow building over water or water-logged ground
• Resist uplift or overturning forces due to wind
• Resist lateral forces due to soil movement
• Underpin (support) existing or unstable structures
• Transmit the load further into the ground to counteract the moment which will occur due to
any horizontal loads
How many types of foundation and what are their performances? - CORRECT
ANSWER • High level / Shallow Types of Foundation
• Low level / Piled Strip footing, Pad (or Spread) footing, Raft (or Mat) footing, Strapped (or
Combined) footing
Shallow:
• Shallow foundations take their name from the level they are founded
• Typically lighter load than deep (piled) foundation
• Much cheaper to construct
• No specialist equipment needed
Deep:
Transferring foundations to a convenient level; a firm soil stratum with sufficient load
carrying capacity
,What are the shallow foundation types? - CORRECT ANSWER • Pad foundation -
Used for relatively light loads or excellent ground conditions such as high level rock (Not
suitable for varying ground conditions)
• Strip footing - Used under walls or where there is a line of closely spaced columns
• Raft (or Mat) footing - Used where ground conditions are reasonably good but variation is
apparent across the site
Sketch the pressure distribution for the pad foundation below subject to uniformly distributed
load - CORRECT ANSWER -
What are the functions, types and characteristics of pile foundation? - CORRECT
ANSWER Pile foundations transfer the load of a structure to denser bedrock deeper
than a shallow foundation similar to a pillar in a building.
Displacement (Driven Piles):
• Timber
• Precast concrete (sometimes prestressed)
• Closed ended steel tube
• Steel "H" sections
Cast in Place:
• Bulb piles
• Bored piers
• Grouted piles
What types of piles resist vertical loads? - CORRECT ANSWER End bearing piles
Friction bearing piles
Combination
Understand how cast in place piles are installed, their advantage and disadvantages. -
CORRECT ANSWER Drill out the hole with the auger
, Steel casing added as a temporary support
Use drilling fluid to remove mud from borehole
Add reinforced cage
Fill with cement
If there is water can fill from the bottom and the water is displaced to the top, at the end the
top part of concrete then needs to be removed as it has been contaminated by the water and
need to refill this part.
What is a CFA pile? - CORRECT ANSWER CFA Continuous Flight Auger.
Continuous Flight Auger (CFA) Piling is the quietest form of piling and is a fast and very
economical technique. It is a cast in-situ process, very suited to soft ground where deep
casings or use of drilling support fluids might otherwise be needed.
What are the contractual issues relating to pile construction? - CORRECT ANSWER •
Contract toe levels
• "Set" verses "penetration"
• Extensions during construction
• Specification of equipment - by client - by contractor
• Responsibility for cutting off head
What are the construction issues relating to large diameter caisson that is built underwater? -
CORRECT ANSWER • Difficulty in keeping water out
• Difficulty generating enough torque to drill through soils
What load tests for piles are there? - CORRECT ANSWER • Sonic Integrity Test (SIT)
• Dynamic Load Test (DLT)
• Static Load Test (SLT)
• Kentledge
What other uses of bored piles beside used to resist vertical loads? - CORRECT
ANSWER • Good for soft and unstable environments
QUESTIONS AND CORRECT ANSWERS
What are the functions of foundation for a building structure? - CORRECT ANSWER •
Support imposed loads
• Prevent settlement (including differential settlement)
• Prevent possible movement of structure due to periodic shrinkage and swelling of subsoil
• Allow building over water or water-logged ground
• Resist uplift or overturning forces due to wind
• Resist lateral forces due to soil movement
• Underpin (support) existing or unstable structures
• Transmit the load further into the ground to counteract the moment which will occur due to
any horizontal loads
How many types of foundation and what are their performances? - CORRECT
ANSWER • High level / Shallow Types of Foundation
• Low level / Piled Strip footing, Pad (or Spread) footing, Raft (or Mat) footing, Strapped (or
Combined) footing
Shallow:
• Shallow foundations take their name from the level they are founded
• Typically lighter load than deep (piled) foundation
• Much cheaper to construct
• No specialist equipment needed
Deep:
Transferring foundations to a convenient level; a firm soil stratum with sufficient load
carrying capacity
,What are the shallow foundation types? - CORRECT ANSWER • Pad foundation -
Used for relatively light loads or excellent ground conditions such as high level rock (Not
suitable for varying ground conditions)
• Strip footing - Used under walls or where there is a line of closely spaced columns
• Raft (or Mat) footing - Used where ground conditions are reasonably good but variation is
apparent across the site
Sketch the pressure distribution for the pad foundation below subject to uniformly distributed
load - CORRECT ANSWER -
What are the functions, types and characteristics of pile foundation? - CORRECT
ANSWER Pile foundations transfer the load of a structure to denser bedrock deeper
than a shallow foundation similar to a pillar in a building.
Displacement (Driven Piles):
• Timber
• Precast concrete (sometimes prestressed)
• Closed ended steel tube
• Steel "H" sections
Cast in Place:
• Bulb piles
• Bored piers
• Grouted piles
What types of piles resist vertical loads? - CORRECT ANSWER End bearing piles
Friction bearing piles
Combination
Understand how cast in place piles are installed, their advantage and disadvantages. -
CORRECT ANSWER Drill out the hole with the auger
, Steel casing added as a temporary support
Use drilling fluid to remove mud from borehole
Add reinforced cage
Fill with cement
If there is water can fill from the bottom and the water is displaced to the top, at the end the
top part of concrete then needs to be removed as it has been contaminated by the water and
need to refill this part.
What is a CFA pile? - CORRECT ANSWER CFA Continuous Flight Auger.
Continuous Flight Auger (CFA) Piling is the quietest form of piling and is a fast and very
economical technique. It is a cast in-situ process, very suited to soft ground where deep
casings or use of drilling support fluids might otherwise be needed.
What are the contractual issues relating to pile construction? - CORRECT ANSWER •
Contract toe levels
• "Set" verses "penetration"
• Extensions during construction
• Specification of equipment - by client - by contractor
• Responsibility for cutting off head
What are the construction issues relating to large diameter caisson that is built underwater? -
CORRECT ANSWER • Difficulty in keeping water out
• Difficulty generating enough torque to drill through soils
What load tests for piles are there? - CORRECT ANSWER • Sonic Integrity Test (SIT)
• Dynamic Load Test (DLT)
• Static Load Test (SLT)
• Kentledge
What other uses of bored piles beside used to resist vertical loads? - CORRECT
ANSWER • Good for soft and unstable environments
