FOUNDATIONS

Question 1

Purpose of a Foundation

Answer 1

To provide a structure the building can safely transfer load to as to resist dead, imposed and wind loads.

To avoid settlement or movement that could cause instability or damage

Question 1

Steps for Setting a Foundation

9

Answer 1

1. Mark space with corner profiles
2. Use 3-4-5 method to attain corner squares
3. Mark space for foundatios with profile boards
4. Excavate
5. Level
6. Shore trenches
7. Insert footing pegs
8. Pour concrete into tenches
9. Level and smooth the concrete to let dry

Question 2

Foundations types

Answer 2

Strip
isolates/Pad
Raft
Pile

Question 3

Derivatives of the Traditional Foundations

Answer 3

Cantilever
Ground Beam
Underpinning

Question 4

Strip Foundations

Answer 4

• Used to carry long, continous loads
• Small buildings
• 1:3:6 (Cement; Sand; Stone)
• 200mm Maximum thickness
• 600mm Maximum length
• Can be reinforced with main and distribution bars

Steep, WIde, Narrow, Deep Types

Question 5

Supported Walls by Strip FOundation

Answer 5

Cavity Wall
One Brick Wall
Half Brick Wall
One & A Half Brick Wall

Question 6

Pad Foundation

Answer 6

• Used under point loads
• Square in plan wherever possible
• Constructed of reinforced concrete
• Width and depth depend on the conditions of the soil and the building’s bearing load

Question 7

Types of Pad foundations

Answer 7

Mass Concrete Pad
Isolated Pad
Rectangular Pad
Combined Coloumn
Steel Grillage

Question 8

Pile Foundation

Answer 8

• Where the strata closer to the surface level is at poor load-bearing capacity, so the building is made to rest on stable strata deeper into the ground
• Reinforcement may be sued to counter moevement of the ground
• Includes reinforeced conrete beam connecting the individual pile heads together
• Ground Beams may be placed ontop of pile caps

Question 9

Types of Piles

Answer 9

End Bearing Piles (Firm Strata)
Friction Pile
Replacement Pile
Displacement Pile (Preformed Pile)

Pile Cap Ontop, Pile itself called a Pile Shaft

Question 10

Raft Foundations

Answer 10

• USed to spread the load over the entire building area
• Can be used for light buildings
• Buildings with heavy loads atop poor, loose soils
• Where top 600mm of subsoil overlies a substrata of poor quality
• Concrete bed that covers the area of propsoed building
• Raft floats on the subsoil like water

Question 11

Types of Raft Foundation

Answer 11

Reinforced Solid Slab
Reinforced Beam and Slab
Cellular

Question 12

Cantilever Foundation

Answer 12

• Used to avoid placing pressure of load on adjacent foundations or underground services