Introduction to Foundation Engineering

Foundation Engineering

1. LINE RODUCILON

2. SYLLABUS of FOUNDATION
ENGINEERING

Soil Exploration

Shallow Foundations

Deep Foundations

Earthen Dams

3. Soil Exploration

Importance of soil exploration and planning of soil
exploration program. Soil exploration methods:
probing, test pits, auger boring, wash boring,
percussion and rotary drilling and geophysical
methods. Disturbed and undisturbed soil
sampling. Soil samplers. Insitu tests: standard
penetration test (SPT), cone penetration test
(CPT), plate load test and field vane shear test.
Bore hole logs and subsoil exploration report.

4. Foundations

Definition, purpose and types of and general
requirements of foundations. Depth of
footings. Selection of foundation type.
Shallow Foundations

Definition of bearing capacity. Methods of
determining bearing capacity. Presumptive
values of bearing capacity. Terzaghi and
Meyerhof’s theories of bearing capacity and
design of isolated, combined and strip
footings. Settlement of shallow foundations
and their remedial measures.

5. Deep Foundations

Introduction to deep foundations. Types of
piles. Load carrying capacity of piles. Group
action. Settlement. Negative skin friction. Pile
load test. Cassion and well foundations.
Earthen Dams

Types of earthen dams, components and their
functions. General design considerations and
typical cross- section.

Foundations on difficult soils

Intoduction to relevant softwares.

7. il Mechanic

John Wiley & Sons, Inc. 1999

8. Reference
Foundation

Analysis
and Design

by Joseph E. Bowles

9. Reference

Foundation
Design

by Donald

P. Coduto

Prentice Hall,1994

10. Definition

Foundation is a part of the structure that
supports the structural weight and transmits
the load to underlying soil or rock.(Foundation

includes foundation structure and soil
influenced by the structural load.)

11. Shallow Foundations versus Deep
Foundations

Foundations
zu
Shallow Deep
Foundations Foundations
I Ey
Spread Mat Driven Drilled Auger Cast
Footings Foundations Piles Shafts Piles

12. Shallow Footings

<= Spread Footing

— bo
Mat Footing Combined Footing

13. c
fe)
=
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T
=
5
O
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©
a

14. Shoes, Snow shoes, and stilts are much like
the different types of footings of a structure

A Shoe make contact with a firm
surface (spread footings)

C. Stilts (pile footings)

= ‘ reach firm surface
B. Snow shoes spread weight

over a large surface (raft footing).

15. Parts of a Foundatior

A foundation (substructure) can
be divided into three parts

Bearing surface.
Footing.
Upright supports.

The bearing surface is the

earth upon which the

foundation rests. It may be soil

or bedrock. The bearing surface y
may be far below the surface of ®&
a swamp, river, or ocean.

16. & The footing is the flat part of the foundation.
It spreads the load of the structure above it.

& Upright support. They may be walls or

piers (masonry column) that rise above the
footing. They form the rest of the structure.

17. Foundation System

Foundation
System

Natural

Foundation | This part will be done

by the Structural
Engineer

Soil Design

18. Every civil engineering structure such as :
Buildings
Bridges.

Highway pavement ,and
Railway track

Will have a superstructure and
substructure(Foundations)

19. Foundation systems

= Superstructure D>

1)
is
5 |
o
=
“u
er
=
€
a
er
© 4
|
o

= eo
= Foundation >

20. Super structure transmits the load.

Sub structure receives and transmits the
load to underlying soil or rock.

The foundation engineer’s aim is that no
component of the structure and foundation
should experience of any kind of distress.

Geotechnical design parameters:
- Bearing capacity
- Settlement

21. SETTLEMENT
No Settlement > 7

Uniform > FEES

Settlement

Differential ==> Ea

Settlement

22. What is Foundation Engineering?

The art of selecting, designing, and constructing
structural support systems based on scientific
principles of soils and engineering mechanics
incorporating accumulated experience with
such applications.

23. What is the current
state-of-the-art?

In spite of the many advances in foundation
engineering it is still an art mostly supported
by empirical techniques.

24. Why mostly empirical?

We do not fully understand the

behavior of foundations.

Knowledge of subsurface conditions
are always limited.

25. What do | have to know to be a
good Foundation Engineer?

Geology

Geophysics

Subsurface Exploration
Laboratory Testing

Soil Mechanics

Structural Engineering

Construction Engineering

26. Uncertainties

Soils:
Not a manufactured material
High degree of variability

Material characterization done based
onasmall sample

Complex behavior (non-linear;
anisotropic)

Rationalism vs. Empiricism
Factors of Safety

27. Who is responsible for
uncertainties?

You (the Foundation Engineer).

Always use presence, common sense
engineering, and experience first, before
blindly following analysis and test results.

28. What is analysis good for?

It is good to confirm that a
precedent solution can be safely

applied to your site.

29. What makes a good
foundation?

Safe
Reliable

Durable
Buildable
Economical

30. Is it my job to be concerned of
costs?

& Yes. As a professional engineer, it is your
obligation to balance “costs and
uncertainties

31. The Final Question

In Foundation Engineering, there are
many “if’s” and “but's”. What do I do
when I am in doubt?

1. When in doubt go wide.

2. When in doubt go deep.
3. When in doubt grout (ground modify).

33. Driven Piles

34. Drilled Pier

35. TA Pile

36. Pier Drilling

37. Caissons

38. H-Pile Installation

39. Geotechnical /Structural Issues

EN À

Structure
Type

Subsurface

Exploration

40. Foundation Design

Eiffel Tower, Paris, France,
built in 1887-1889

41. Transcosna Grain Elevator canada (Oct. 18,
1913)

42. Foundation Design

Leaning Tower, Pisa, Italy f
Built 1173-1350

43. Palacio de las Bellas
n Artes, Mexico City
Built 1932-1934

44. Tower of Latino
Americana, Mexico City
Built in 1956

44 stories; 597-ft

45. Performance Requirements

Design Loads

Allowable Stress Design vs LRFD
Performance Requirements
Strength Requirements
Serviceability Requirements
Total Settlement

Differential Settlement
Constructability Requirements
Economic Requirements

46. Strength Requirements

Foundation
soil must be
strong
enough to

support
imposed

48. Settlement must
be within
acceptable limits

49. al

Total vs. Differential Settlement_

50. Determining the type of foundation for the structure,
including the depth and dimensions
Calculating the potential settlement of the foundation

i Determining the expansion potential

i Investigating the stability of slopes and their effect on
adjacent foundations

Investigating the possibility of foundation movement
due to seismic forces, which would also include the
possibility of liquefaction

51. Performing studies and tests to determine the potential
for deterioration of the foundations
Evaluating possible soil treatment to increase the

foundation bearing capacity

Determining design parameters for retaining wall
foundations

Providing recommendations for dewatering and
drainage of excavations needed for the construction of
the foundation

52. & Investigating ground water and seepage problems and

developing mitigation measures during foundation
construction

& Site preparation, including compaction specifications
and density testing during grading
& Underpinning and field testing of foundations

53. Knowledge of the general topography of the site
The location of buried utilities

The geology of the proposed site

The previous history and use of the site

Any special features such as the possibility of

earthquakes or climate factors such as flooding ,

seasonal swelling and shrinkage, permafrost, or soil

erosion

54. & The availability and quality of local construction materials

B For maritime or river structures, information on tidal ranges
and river levels, velocity of tidal and river currents, and other
hydrographic and meteorological data

& A detailed record of the soil and rock strata and ground water
conditions within the zones affected by foundation bearing
pressure and construction operations

55. & Results of laboratory tests on soil and
rock samples appropriate to the
particular foundation design or

construction problems

& Results of chemical analyses on soil and

ground water to determine possible
deleterious of foundation structures

56. Preliminary Information and Planning
the Work

Project Location

Basic information on the location of the project is

required. The location of the project can be compared
with known geological hazards such as active faults,
landslides, or deposits prone to liquefaction.

Type of Project

It is important to obtain as much information about the
project as possible.

57. Such information could include the type of structure and use,
size of the structure including the number of stories, type of
construction and floor systems, preliminary foundation type,
and estimated structural loadings.

Scope of work

The scope of the work must be determined, which includes
subsurface exploration and laboratory testing to determine
the feasibility of the project, the preparation of foundation
design parameters, and compaction testing during the grading
of the site in order to prepare the building pad for foundation
construction.

58. After the preliminary information is obtained, the next
step is to plan the foundation investigation work.

For minor project, the planning effort may be minimal,
but for large-scale projects, the plan could be quite
extensive and could change as the design and
construction progresses.

59. The planning effort could include the following:
Budget and scheduling considerations

Selection of a team of professionals of relevant fields

(such as geotechnical engineer, engineering geologist,

structural engineer, hydro geologist and the like)that will
work on the project

Preliminary subsurface exploration plan, such as number
, location, and depth of borings

60. Document collection
Laboratory testing requirements
& Types of engineering analyses

that will be required for the design
of the foundation.