2. INTRODUCTION
Building Foundation is an underground
structure that directly in contact with the soil
and spread the load of building to the ground
so as to limit the soil settlement of the building.
In certain circumstances, it is also to withstand
the wind pressure.
3. FUNCTION
Spread the load of building structures to the
broader and stronger area.
Spreading the load with uniform and constantly
(avoid differential settlement)
To strongly hold the frame of building,
especially in high-rise buildings
Prepare a hard and flat surface
4. REQUIREMENTS
Located in a safe place and to distribute all
loads such as dead load, live load and wind
load in an appropriate manner.
Sufficient in depth
Resistant to sulfate attack
5. TYPE OF FOUNDATIONS
Shallow foundation
Strip
Pad
Raft
Deep Foundation
Piling
Hollow basement, caisson
6. DESIGN CRITERIA FOR FOUNDATION
Good foundation design is to ensure that the
structure load including the mass of
foundation distributed by:
Economical
Safe
No movement during or after construction
7. METHODS IN FOUNDATION DESIGN
Site Investigation
Magnitude and distribution of loads from the
structure is divided by dead load, life load and
vibration (dynamic loading) and also wind
pressure.
Overall total of settlement and the differential
settlement
Foundation Types
Allowable bearing pressure value of load
8. CONT…
Pressure distribution under foundation
calculation
Analysis of settlement
Foundation material
Structure design
working drawing
9. LOAD BEARING CAPACITY
Ultimate bearing capacity
Safe bearing capacity
Load bearing strength is determined by the
following :
a) Ranking Analysis
b) Penetration Test
c) Persumptive value
10. METHODS TO INCREASE LOAD BEARING
CAPACITY
Increase the depth of foundation
soil compaction:
a. Vibration
b. Preloading
c. Water flowing
d. Grouting
11. SETTLEMENT
Definition: Downward vertical movement due to
the load pressure on them. Divided into two
a) Immediate settlement-occur when the soil is
imposed by the load from soil elastic
deformation where it does not change the
water content
b) Consolidation Settlement-reduction in the
volume of soil due to water flowing out from the
grain cavities.
12. CAUSES OF SETTLEMENT
Structure pressure to the ground
Changes in soil water content
The vibration caused by impact piling, blasting
and heavy machinery.
Expansion and contraction of soil
Movement / soil erosion
Other causes, such as soil digging in the nearby
area
13. DIFFERENTIAL SETTLEMENT
Definition: the relative settlement between one
part of the building to the other part of building
and cause the stress that can result building to
crack or collapse
14. SOURCES OF DIFFERENTIAL SETTLEMENT
Differences in soil layers in a single site
The difference in the load structure
Large load area
The time difference between the construction
of other parts of the building
Differences in site conditions.
15. METHODS TO REDUCE DIFFERENTIAL
SETTLEMENT
Use raft foundation with a thick slab
Use deeper underground space to reduce
pressure on soil.
Transfer load to the stronger and not easily
compressible soil with the foundation applied
such as piles, caisson, etc.
Method of repair of soil - increase in soil
strength
16. SELECTION OF FOUNDATION’S TYPE
Condition and soil strength
The nature and type of building
The total loads of building
Surrounding area
Cost
