Course
Year
Version
: S0484/Foundation Engineering
: 2007
: 1/0
Session 1 – 2
INTRODUCTION
GENERAL
SCOPE OF THE COURSE
• Introduction (Definition, type of foundation, review of Soil
Mechanics Principles)
• Bearing Capacity of Soil
• Shallow foundations (type, design and settlement of
foundation)
• Sheet Pile Structure (lateral earth pressure, design of sheet
pile)
• Deep Foundation (Single pile, Group pile, settlement of pile)
• Installation of pile and test of pile capacity
• Application of shallow, deep foundation and sheet pile
structure
GENERAL
Grading Policy
• Home Work ………........................
• Mid Semester Test ……………….
• Final Test …..................................
TOTAL .....................
20%
30%
50%
100%
Note:
• Appropriate changes to this grading policy may be made with
student consent.
REFERENCE TEXTBOOK
REFERENCE TEXTBOOK
SUPPORTING
TEXTBOOK
COURSE 1
Content:
• Definition
• Design Criteria
• Soil investigation, laboratory tests and soil
properties related to structure designs
DEFINITION
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.
A scientifically Acceptable Answer
DEFINITION
What is Foundation Engineering?
Foundation Engineering is the art and science of
molding materials we do not fully understand into
shapes we can not precisely analyze to resist
forces we can not accurately predict, all in such a
way that the society at large is given no reason to
suspect of our ignorance.
Not so scientifically Acceptable Answer – addopted from Coduto
FOUNDATION TYPES
• Shallow Foundations.
Shallow foundations are usually placed within a depth D
beneath the ground surface less than the minimum width
B of the foundation. Shallow foundations consist of
spread and continuous footings, wall footings and mats.
FOUNDATION TYPES
•
Deep Foundations.
Deep foundations can be as short as
15 to 20 ft or as long as 200 ft or
more and may consist of driven piles,
drilled shafts or stone columns. A
single drilled shaft often has greater
load bearing capacity than a single
pile. Deep foundations may be
designed to carry superstructure
loads through poor soil (loose sands,
soft clays, and collapsible materials)
into competent bearing materials.
Even when piles or drilled shafts are
carried into competent materials,
significant settlement can still occur if
compressible soils are located below
the tip of these deep foundations.
Deep foundation support is usually
more economical for depths less than
100 ft than mat foundations.
DESIGN CRITERIA
THE DESIGN SHOULD BE:
- SAFE
- RELIABLE
- DURABLE
- BUILDABLE
- ECONOMIC
DESIGN DATA
•
•
•
•
SOIL DATA
GROUND WATER DATA
GEOMETRY DATA
DATA OF LOAD
SOIL DATA
DETERMINED FROM:
- FIELD INVESTIGATION
-
CPT
SPT
VANE SHEAR TEST
PRESSUREMETER TEST
- LABORATORY TEST
-
INDEX TEST
TRIAKSIAL
DIRECT SHEAR
UNCONFINED
CONSOLIDATION
STANDARD PENETRATION TEST (SPT)
• ADVANTAGES
– Could be used to identify soil types visually
– Could be used to get qualitative soil properties by
empirical correlation
• LIMITATION
– The soil strength profile can not be measured
continuously
– The high accuracy is needed during investigation
in case of weight and fall height of hammer
HAMMER OF SPT
DIMENSION OF SPT TUBE
SPT EXECUTION
SPT PROFILE (EXAMPLE)
CONE PENETRATION TEST (CPT)
• TYPES OF TOOL AND PRINCIPLE OF WORK
– Mechanical friction-cone penetrometer
by pushing a cone with projection area 10 cm2 and
60o angle and standard velocity 20 mm per-second.
2 measurement parameters each 20 cm of depth:
• Cone Resistance (qc)
• Local Friction (fs)
– Electric friction-cone penetrometer
measure the cone pressure and continuously friction
with better accuracy level
CONE PENETRATION TEST (CPT)
• ADVANTAGES
– Continuous Soil strength profile
– Give fast description of soil
– Simple
• LIMITATION
– The accuracy is bad for soil with some stones
– Mechanical friction-cone penetrometer is less
sensitive when applied in very soft clay
UKURAN KONUS SONDIR (ASTM D 3441)
ELECTRIC CONE DIMENSION
CPT RESULT (EXAMPLE)
LABORATORY TESTS
• Soil Index (, , e, GS dll.)
– Measuring of volume and mass of sample
– Sieve analysis test
– Atterberg Test
• Shear Strength of Soil (c, )
– Triaksial Test (UU, CU, CD)
– Direct Shear
– Unconfined Compression Test
• Compressibility (Cc, Cv)
– Consolidation Test
• Permeability (k)
– Constant Head
– Falling Head
EMPIRICAL CORRELATION
• SPT Data
EMPIRICAL CORRELATION
• CPT Data
EMPIRICAL CORRELATION
• Between Soil Properties
– Cc = 0,009 (LL – 10)
– C = qu/2
– C = 19 – 23 CBR (C in kN/m2)