Transcript Document

Practical Implementation of LRFD for
Geotechnical Engineering Features
Design and Construction of Driven Pile Foundations
Wednesday, June 22, 2011
PDCA Professors Workshop
By
Jerry A. DiMaggio, PE, D. GE, M. ASCE
E-Mail: [email protected]
1
ASCE LRFD Webinar Series
#
Topic
2009
2010
2011
1
Fundamentals of LRFD – Part 1
1/16, 8/7
6/30
1/18, 10/13
2
Fundamentals of LRFD – Part 2
1/30, 9/8
7/15
2/4, 10/21
3
Subsurface Explorations
6/30, 11/5 4/15
2/17, 8/18
4
Shallow Foundations
7/24
5/20, 12/12
5
Deep Foundations – Piles
1/25, 6/1, 12/14 6/21, 11/7
6
Deep Foundations – Shafts
2/8, 6/11
1/7, 7/8
1/23
7
Deep Foundations – Micropiles
9/10
3/3, 7/29
1/12
8
Earth Retaining Structures – Fill
8/20
3/11, 9/12
3/9
9
Earth Retaining Structures – Cut
10/21
9/30
2/28
10
MSE Walls
4/4, 12/2
11
Ground Anchors
5/2
1/6, 5/7, 11/8
2012
2/3
3/29
* Check ASCE website for latest information
2
Presnetation Assumptions/References
• Basic knowledge of:
– LRFD (previous webinars)
– Basic Deep Foundation Design and Construction
• Primary References:
– Section 10 of AASHTO (2010, 5th Edition)
– List of other references provided at end
3
Driven Pile Foundations
Topic
Slides
General (Section 3, Section 10.4, 10.7.1)
4 – 18
10.5 Limit States and Resistance Factors 19 – 22
10.7.2 Service Limit State
23 – 31
10.7.3 Strength Limit State
32 – 58
10.7.4 Extreme Event Limit State
59 – 65
10.7.5 Corrosion and Deterioration
66 – 69
10.7.8 Drivability Analysis
70 – 73
4
Section 10 Contents
Article
10.1
Topic
Scope
10.2
10.3
10.4
10.5
Definitions
Notation
Soil and Rock Properties
Limit States and Resistance Factors
10.6
10.7
10.8
Spread Footings
Driven Piles
Drilled Shafts
10.9
Micropiles
Refer to Section 3 for Loads and Load Factors
5
Deep Foundation Types
Material
Driven
Piles
Drilled
Jacked/
Shafts/
Special
Micropiles
Prestressed concrete
X
X
Post-tensioned concrete
X
Pre-cast concrete
X
Cast-in-place concrete
X
X
X
Steel
X
X
X
Wood
X
Specialty/Composites
X
X
X
X
6
Section 10.7 Driven Piles
Article
10.7.1
Topic
General
10.7.2
10.7.3
10.7.4
Service Limit State Design
Strength Limit State Design
Extreme Event Limit State Design
10.7.5
10.7.6
10.7.7
10.7.8
Corrosion and Deterioration
Minimum Pile Penetration
Driving Criteria for Bearing
Drivability Analysis
10.7.9
Test Piles
7
Professional Discipline Communication
• Geotechnical, Structural, Hydraulic, and Construction
specialists all play an important role and have
different responsibilities on deep foundation
projects.
• Project specific loads, extreme events, performance
requirements, scour, pile cap details, specifications,
plans construction, pile damage are ALL KEY issues
for a successful project!
• The Geotechnical Design Report is a key
communication tool.
8
10.7.1 GENERAL
• Consider spread footings first.
• Basic guidelines for driven pile configurations
– Minimum spacing 2.5 pile diameters or 30 inches.
– Minimum of 9 inches pile cap edge and be embedded 12
inches into the pile cap or if with strands or bars then the
pile embedment should be 6 inches.
– Piles through embankments should extend 10 ft into
original ground or refusal on rock. Maximum of 6 inch fill
size.
– Batter Piles: stiffness, don’t use in downdrag situations,
concern in seismic situations.
9
Comparison of LRFD and ASD approaches
for Deep Foundations
Same
Different
• Determining resistance
• Comparison of load and resistance
• Determining deflection
• Separation of resistance and deflection
10
AASHTO Table 3.4.1-1
Load
Combination
Limit State
I
II
STRENGTH
III
LIMIT
IV
V
I
EXTREME
II
EVENT
I
II
SERVICE LIMIT
III
IV
I
FATIGUE - LL,
II
IM & CE only
DC
DD
DW
EH
EV
ES
EL
PS
CR
SH
γp
γp
γp
γp
γp
γp
γp
1.00
1.00
1.00
1.00
—
—
Use One of These at
a Time
LL
IM
CE
BR
PL
LS
1.75
1.35
—
—
1.35
γEQ
0.50
1.00
1.30
0.80
—
1.50
0.75
WA
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
—
—
WS
—
—
1.40
—
0.40
—
—
0.30
—
—
0.70
—
—
WL
—
—
—
—
1.0
—
—
1.0
—
—
—
—
—
FR
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
—
—
TU
0.50/1.20
0.50/1.20
0.50/1.20
0.50/1.20
0.50/1.20
—
—
1.00/1.20
1.00/1.20
1.00/1.20
1.00/1.20
—
—
TG
γTG
γTG
γTG
—
γTG
—
—
γTG
—
γTG
—
—
—
SE
γSE
γSE
γSE
—
γSE
—
—
γSE
—
γSE
1.0
—
—
EQ
—
—
—
—
—
1.00
—
—
—
—
—
—
—
IC
—
—
—
—
—
—
1.00
—
—
—
—
—
—
CT
—
—
—
—
—
—
1.00
—
—
—
—
—
—
CV
—
—
—
—
—
—
1.00
—
—
—
—
—
—
11
EH
EV
ES
DC
DD
Load
Combination
Limit State
I
II
STRENGTH
III
LIMIT
IV
V
I
EXTREME
II
EVENT
I
II
SERVICE LIMIT
III
IV
I
FATIGUE - LL,
II
IM & CE only
DW
DC
DD
DW
EH
EV
ES
EL
PS
CR
SH
γp
γp
γp
γp
γp
γp
γp
1.00
1.00
1.00
1.00
—
—
Use One of These at
a Time
LL
LL
IM
CE
BR
PL
LS
1.75
1.35
—
—
1.35
γEQ
0.50
1.00
1.30
0.80
—
1.50
0.75
EQ
CT
WA
WA
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
—
—
WS
—
—
1.40
—
0.40
—
—
0.30
—
—
0.70
—
—
WL
—
—
—
—
1.0
—
—
1.0
—
—
—
—
—
FR
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
—
—
TU
0.50/1.20
0.50/1.20
0.50/1.20
0.50/1.20
0.50/1.20
—
—
1.00/1.20
1.00/1.20
1.00/1.20
1.00/1.20
—
—
TG
γTG
γTG
γTG
—
γTG
—
—
γTG
—
γTG
—
—
—
SE
γSE
γSE
γSE
—
γSE
—
—
γSE
—
γSE
1.0
—
—
EQ
—
—
—
—
—
1.00
—
—
—
—
—
—
—
IC
—
—
—
—
—
—
1.00
—
—
—
—
—
—
CT
—
—
—
—
—
—
1.00
—
—
—
—
—
—
CV
—
—
—
—
—
—
1.00
—
—
—
—
—
—
12
Load Factors for Permanent Loads, gp
AASHTO Table 3.4.1-2
Type of Load, Foundation Type, and
Method Used to Calculate Downdrag
DC: Component and Attachments
DC: Strength IV only
DD: Downdrag
Piles,  Tomlinson Method
Piles,  Method
Drilled shafts, O’Neill and Reese (1999) Method
DW: Wearing Surfaces and Utilities
EH: Horizontal Earth Pressure
 Active
 At-Rest
 AEP for anchored walls
EL: Locked-in Construction Stresses
EV: Vertical Earth Pressure
 Overall Stability
 Retaining Walls and Abutments
 Rigid Buried Structure
 Rigid Frames
 Flexible Buried Structures other than Metal Box Culverts
 Flexible Metal Box Culverts and Structural Plate Culverts with Deep
Corrugations
ES: Earth Surcharge
Load Factor
Maximum
Minimum
1.25
1.50
1.4
1.05
1.25
1.50
0.90
0.90
0.25
0.30
0.35
0.65
1.50
1.35
1.35
1.00
0.90
0.90
N/A
1.00
1.00
1.35
1.30
1.35
1.95
N/A
1.00
0.90
0.90
0.90
1.50
0.90
1.50
0.75
13
Load Type and Direction
Structural
• Vertical or horizontal
• Permanent/Transient
Geotechnical
• Vertical/Horizontal
• Downdrag/Setup/Relaxation
Bridge Deck
New
Fill
Soft Soil Consolidating
Due to Fill Weight
Bearing Stratum
14
Downdrag
• “Geotechnical” load
• Can be significant
particularly given the
max load factors
• Articles 3.4.1 and
3.11.8
Bridge Deck
New
Fill
Design Method
-method
Piles
-method
Shafts Reese & O’Neill (1999)
Soft Soil Consolidating
Due to Fill Weight
Bearing Stratum
Load Factors
Maximum Minimum
1.40
0.25
1.05
0.30
1.25
0.35 15
15
AASHTO Section 10.4
Soil and Rock Properties
Article
Topic
10.4.1
10.4.2
10.4.3
10.4.4
Informational Needs
Subsurface Exploration
Laboratory Tests
In Situ Tests
10.4.5
10.4.6
Geophysical Tests
Selection of Design Properties
DISCUSSED IN PREVIOUS WEBINAR ON
SUBSURFACE INVESTIGATIONS – Next Offering
on August 18, 2011
16
Deep Foundation Selection
•
•
•
•
•
Method of support
Bearing material depth
Load type, direction and magnitude
Constructability
Cost
 Expressed in $/kip capacity
 Include all possible costs
17
Pile Types Based on Soil Displacement
During Driving
Low Displacement
High Displacement
18
Driven Pile Foundations
Topic
Slides
General (Section 3, Section 10.4, 10.7.1) 4 – 18
10.5 Limit States and Resistance Factors 19 – 22
10.7.2 Service Limit State
23 – 31
10.7.3 Strength Limit State
10.7.4 Extreme Event Limit State
10.7.5 Corrosion and Deterioration
32 – 58
59 – 65
10.7.8 Drivability Analysis
70 – 73
66 – 69
19
Strength Limit State Driven Piles
ARTICLE 10.5.3.3
•
•
•
•
•
•
•
Axial compression resistance for single piles
Pile group compression resistance
Uplift resistance of single piles
Uplift resistance of pile groups
Pile punching failure in weaker stratum
Single pile and pile group lateral resistance
Constructability, including pile drivability
20
SPECIAL DESIGN CONSIDERATIONS
•
•
•
•
•
Negative shaft resistance (downdrag)
Lateral squeeze
Scour
Pile and soil heave
Seismic considerations
21
10.5 LIMIT STATES AND RESISTANCE
• Strength Limit State (will be discussed later)
– Structural Resistance
– Geotechnical Resistance
– Driven Resistance
• Service Limit State
– Resistance Factor = 1.0 (except for global stability)
• Extreme Event Limit State
– Seismic, superflood, vessel, vehicle
– Use nominal resistance
22
Driven Pile Foundations
Topic
Slides
General (Section 3, Section 10.4, 10.7.1) 4 – 18
10.5 Limit States and Resistance Factors 19 – 22
10.7.2 Service Limit State
23 – 31
10.7.3 Strength Limit State
10.7.4 Extreme Event Limit State
10.7.5 Corrosion and Deterioration
32 – 61
62 – 65
10.7.8 Drivability Analysis
70 – 73
66 – 69
23
Service Limit State Checks
Global Stability
Vertical and
Horizontal
Displacements
24
Settlement of Pile Groups
Article 10.7.2.3.1 [Hannigan (2006)]
• Treat as
equivalent
footings
• Categorize
as one of
the 4 cases
shown
here
25
10.7.2.4 Horizontal Loads and Pile Moments
Fx
M2
Dx
Dx
H2
M1
H1
26
Horizontal Response
Isolated
Group
• Assumes nominal resistance is adequate
• No consideration of possible brittle response
of geomaterial
• LPILE type p-y model or Strain Wedge Method
27
P-y Results for Single Element
-0.2 0
0.2 0.4 0.6 0.8
0.84
Depth, ft
10.1 k
1740 k
8000 in-k Deflection, Moment,
in.
in. -kx102
0
Shear,
k
20 40 60 80 -60 -40 -20
0
20
8640
10
20
65.5
30
40
50
28
P-y Results for Pile Groups
AASHTO Figure 10.7.2.4-1
Row
1
Row
2
Row
3 or higher
Row
1
Row
2
Row
3 or higher
Applied Load
Spacing
Spacing
B
Applied Load
5B or less
Row 1
Applied Load
Spacing (S)
P-multiplier (Pm)
Row 1
Row 2
Row 3
3B
0.8
0.4
0.3
5B
1.00
0.85
0.7
29
Pile Head Fixity
Dx
Dx
Moment
Moment
30
30
Tolerable Movements and Movement
Criteria 10.5.2.2
• Service loads for settlements,
horizontal movements and
rotations.
• Omit transient loads for
cohesive soils
• Reference movements to the
top of the substructure unit.
• Angular Distortion (C10.5.2.2)
31
Driven Pile Foundations
Topic
Slides
General (Section 3, Section 10.4, 10.7.1) 4 – 18
10.5 Limit States and Resistance Factors 19 – 22
10.7.2 Service Limit State
23 – 31
10.7.3 Strength Limit State
10.7.4 Extreme Event Limit State
10.7.5 Corrosion and Deterioration
32 – 58
59 – 65
10.7.8 Drivability Analysis
70 – 73
66 – 69
32
STRENGTH LIMIT STATES
Axial
Structural
Driven
(Assess Drivability)
Flexure
Shear
Geotechnical Axial
33
33
Methods for Determining Structural
Resistance
Axial compression
Combined axial and flexure
Shear
Concrete – Section 5
LRFD
Specifications
Steel – Section 6
Wood – Section 8
34
Factors Affecting
Allowable Structural Pile Stresses
• Average section strength (Fy, fc’, wood crushing
strength)
• Defects (knots in timber)
• Section treatment (preservation for timber)
• Variation in materials
• Load factor (overloads or pile damage)
35
Structural Resistance Factors
10.7.3.13 Pile Structural Resistance
Concrete (5.5.4.2)
Steel (6.5.4.2)
Axial Comp. = 0.75
Axial = 0.5-0.7
Flexure = 0.9 (strain dependent) Combined
Shear = 0.9
Axial= 0.7-0.8
Flexure = 1.0
Shear = 1.0
LRFD
Specifications
Timber (8.5.2.2 and .3)
Compression = 0.9
Tension = 0.8
Flexure = 0.85
Shear = 0.75
36
Determining Nominal Axial Geotechnical
Resistance of Piles
Field methods
Static load test
 Dynamic load test (PDA)
 Driving Formulae
 Wave Equation Analysis

Static analysis methods
37
Geotechnical Safety Factors for Piles (ASD)
Basis for Design and Type
of Construction Control
Subsurface exploration
Static analysis
Dynamic formula
Wave equation
CAPWAP analysis
Static load test
Factor of Safety (FS)
Increasing Design/Construction
Control
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
3.50 2.75 2.25 2.00 1.90
38
Pile Testing Methods
2.75
X
2.25
X
0.65 or
0.75
0.75 to
0.80
2.00
X
X
Energy
0.50
Stress
X
Measured
Capacity
3.50
Energy
0.10 or
0.40
Stress
Factor of
Safety
(FS)
(AASHTO 2010)
Dynamic
formula
Wave
equation
Dynamic
testing
Static load
test
Estimated
Capacity
Analysis
Method
Resistance
Factor
(f)
X
X
X
39
Geotechnical Nominal Resistance of Piles:
Static Load Tests ASTM D1143 (10.7.8.2)
Test Setup
Results and Definition
of Failure
40
Dynamic Load Test (PDA) ASTM D4945
10.7.3.8.3
41
Wave Equation Driven Resistance
10.7.3.8.4
vo
Ram
Cushion
elastic
Drivehead
elastic
c
Compressive
Force Pulse
(Incident)
Ground
Surface
Compressive
Force Pulse
(Attenuated)
Pile
Soft Layer
Compressive
Force Pulse
c
Tensile or
Compressive
Force Pulse c
(Reflected)
(a)
Dense
Layer
(b)
(c)
c
Permanent Set
(d)
42
Wave Equation Applications
Item
Use
Develop driving
criterion
• Blow count for a required nominal
resistance
• Blow count for nominal resistance as a
function of energy/stroke
Check drivability
• Blow count vs penetration depth
• Driving stresses vs penetration depth
Determine optimal
driving equipment
• Driving time
Refined matching
analysis
• Adjust input values based on dynamic
measurements
43
1480 kN
U ltim a t e C a p a c ity ( k N )
250
200
200
150
150
100
100
50
50
0
0
2000
27-Aug-2003
GRLWEAP (TM) Version 2003
DELMAG D 12-42
Efficiency
0.800
Helmet
Hammer Cushion
7.60 kN
10535 kN/mm
Skin Quake
Toe Quake
Skin Damping
Toe Damping
2.500
3.000
0.160
0.500
Pile Length
Pile Penetration
Pile Top Area
20.00 m
19.00 m
86.51 cm2
Pile Model
Skin Friction
Distribution
mm
mm
sec/m
sec/m
5.00
1600
4.00
1200
3.00
2.6 m
800
2.00
400
1.00
0
0.0
T e n s io n S tr e s s ( M P a )
195 MPa
250
25.0
50.0
75.0
100.0
Blow Count (blows/.25m)
68 blows / 0.25 m
125.0
0.00
150.0
S t r o k e ( m e te r )
C o m p r e s s iv e S tr e s s ( M P a )
Wave Equation Results
GRL Engineers, Inc.
FHWA - GRLWEAP EXAMPLE #1
Res. Shaft = 84 %
(Proportional)
44
Driving Formulas
(Article 10.7.3.8.5)
45
Pile Testing Methods
X
0.65 or 0.75
X
0.75 to 0.80
X
X
Energy
0.50
Stress
X
Measured
Capacity
0.10 or 0.40
Energy
Static load
test
(AASHTO 2010)
Stress
Dynamic
formula
Wave
equation
Dynamic
testing
Estimated
Capacity
Analysis
Method
Resistance
Factor
(f)
X
X
X
46
Static analysis methods and computer solutions
are used to:
● Calculate pile length for loads
● Determine number of piles
● Determine most cost effective pile type
● Calculate foundation settlement
● Calculate performance under uplift and lateral loads
47
Static Analysis Methods
• Primary use is for pile length estimation for
contract drawings and feasibility.
• Secondary use for estimation of downdrag,
uplift resistance and scour effects
• Should rarely be used as sole means of
determining pile resistance. ONLY IN SPECIAL
SITUATIONS!
48
Large Pile Diameter Resistance
Total Resistance
Resistance
A
Side Resistance
D
B
C
Tip Resistance
RS
RP
Vertical Displacement
RR = fRn = fqpRp + fqsRs
49
Computation of Static Geotechnical Resistance
RR = fRn
fRn = fqpRp + fqsRs
R P = AP q P
RS
RP
RS = AS qs
AASHTO 10.7.3.7.5-2
50
EXAMPLE SOIL PROFILE
Nominal Resistance: Rn = Rs1 + Rs2 + Rs3 +Rt
Factored Resistance: RR = fRn= f(Rs3 + Rt)
Soil Resistance
to Driving (SRD):
SRD = Rs1 + Rs2 + Rs3 +Rt
((with no soil strength changes)
SRD = Rs1 + Rs2 / 2 + Rs3 +Rt
(with clay soil strength change)
51
Static Analysis Methods
Driven Piles
 method
b method
 method
Nordlund -Thurman method
SPT-method
CPT-method
52
Resistance Factors Static Analysis Methods
AASHTO Table 10.5.5.2.3-1
Method
- method
b- method
- method
Nordlund- Thurman
SPT
CPT
Group
Resistance Factor, f
Compression
Tension
0.35
0.25
0.25
0.20
0.40
0.30
0.45
0.35
0.30
0.25
0.50
0.40
0.60
0.50
53
Combining Geotechnical Resistance Factors
• C10.7.3.3 fdyn x Rn = f stat x Rnstat
• The length predicted by this method may be
overly conservative and need to be adjusted
to reflect experience.
• Local experience replaces this suggested
relationship.
54
Driven Pile Time Dependent Effects
(Article 10.7.3.4)
Setup
RS
RP
Relaxation
RS
RP
RS
RP
RS
RP
55
SOIL SETUP
• Soil setup is a time dependent increase in the static
pile resistance
• Large excess positive pore pressures are often
generated during pile driving
• Soil setup frequently occurs for piles driven in
saturated clays as well as loose to medium dense
silts and fine sands as the excess pore pressure
dissipate
• Magnitude of setup depends on soil characteristics
and pile material and type
56
Point Bearing on Rock
(Article 10.7.3.2)
• Soft rock that can be penetrated by pile driving may be
treated similar to soils.
• Steel piles driven into soft rock may not require tip
reinforcement.
• On hard rock the nominal resistance is controlled by
the structural capacity. See Article 6.9.4.1 and the
driving resistances in 6.5.4.2 and 6.15 for severe
driving.
• PDA should be used when the nominal resistance
exceeds 600 kips.
• C10.7.3.2.3 Provides qualitative guidance to minimize
pile damage when driving piles on hard rock.
57
Pile Group Resistance 10.7.3.9 & 11
Static Geotechnical Resistance
Figures 10.7.3.11-1 and -2 for group uplift resistance for cohesionless and
cohesive soils respectively.
Take lesser of
58
Driven Pile Foundations
Topic
Slides
General (Section 3, Section 10.4, 10.7.1) 4 – 16
10.5 Limit States and Resistance Factors 17 – 20
10.7.2 Service Limit State
21 – 29
10.7.3 Strength Limit State
10.7.4 Extreme Event Limit State
10.7.5 Corrosion and Deterioration
30 – 58
59 – 65
10.7.8 Drivability Analysis
70 – 73
66 – 69
59
EXTREME EVENT LIMIT STATES
10.5.5.3
• Scour
• Vessel and Vehicle collision
• Seismic loading and site specific situations.
(Uplift Resistance should be 0.80 rather than
1.00 for all extreme checks.)
60
Piles Subject to Scour
10.5.5.3.2
61
Seismic – Articles 10.7.4, 10.5.5.3.3
• Liquefaction: Neglect axial resistance in
liquefiable zone
• Lateral Spreading: Either consider forces due
to lateral spreading or improve ground;
reduce P-y curve based on duration of strong
shaking and ability of the ground to fully
liquefy during strong shaking
• Downdrag: Do not combine “seismic”
downdrag with “static” downdrag
62
Driven Pile Foundations
Topic
Slides
General (Section 3, Section 10.4, 10.7.1) 4 – 18
10.5 Limit States and Resistance Factors 19 – 22
10.7.2 Service Limit State
23 – 31
10.7.3 Strength Limit State
10.7.4 Extreme Event Limit State
10.7.5 Corrosion and Deterioration
32 – 58
59 – 62
10.7.8 Drivability Analysis
67 – 73
63 – 66
63
10.7.5 Corrosion and Deterioration
• Identified by soil resistivity & pH testing
• If pH < 4.5, design should be based on an aggressive
environment
• Corrosion of steel pile foundations, particularly in
fill soils, low pH soils and marine environments
• Sulfate, chloride, and acid attack of concrete pile
foundations
• Decay of timber piles from wetting and drying
cycles from insects and marine borers
64
Aggressive Subsurface Environments
• Resistivity < 2000 ohms-cm
• pH < 5.5
• pH between 5.5 and 8.5 in soils with high
organic content
• Sulfates > 1,000 ppm
• Landfills and cinder fills
• Soils subject to mine or industrial drainage
• Areas of mixed resistivity (high and low)
• Insects (wood piles)
65
Pile Driving Induced Vibrations
See Hannigan (2006)
• Vibration induced damage
• Vibration induced soil densification
66
Driven Pile Foundations
Topic
Slides
General (Section 3, Section 10.4, 10.7.1) 4 – 18
10.5 Limit States and Resistance Factors 19 – 22
10.7.2 Service Limit State
23 – 31
10.7.3 Strength Limit State
10.7.4 Extreme Event Limit State
10.7.5 Corrosion and Deterioration
32 – 58
59 – 62
10.7.8 Drivability Analysis
67 – 73
63 – 66
67
Section 10.7.8 Driven Piles
Comp Str
ksi
Tens Str
ksi
30
Requirements for
drivability analysis
have been added
and clarified
20
10
Ult Cap
kips
Stroke
800
ft
16.0
600
12.0
400
8.0
200
4.0
0
160
320
480 Blows/ft
68
Pile Type
Loading Type
Limiting Driving Stress
Steel
Compression/Tension
 dr fda (0.9 f y )
Compression
dr  fda (0.85fc' )
Tension
dr  fda (0.7 fy )
Compression
dr  fda (0.85 fc'  fpe)
Tension
dr  fda (0.095 fc'  fpe)
Tension (in severe
corrosion)
dr  fda (fpe)
Compression/Tension
dr  fda (fco)
Concrete
Prestressed
Timber
69
Driven Resistance Factors
Concrete piles,fda= 1.00

AASHTO Article 5.5.4.2.1
Steel piles,fda= 1.00

AASHTO Article 6.5.4.2
Timber piles,fda= 1.15

AASHTO Article 8.5.2.2
70
Driven Pile Foundations
Topic
Slides
General (Section 3, Section 10.4, 10.7.1) 4 – 18
10.5 Limit States and Resistance Factors 19 – 22
10.7.2 Service Limit State
23 – 31
10.7.3 Strength Limit State
10.7.4 Extreme Event Limit State
10.7.5 Corrosion and Deterioration
32 – 58
59 – 62
10.7.8 Drivability Analysis
67 – 71
63 – 66
71
5th Edition 2010 Changes Sec 10.5
• Specification references to changes in resistance factors based on
pile group size moved to the commentary.
• The definition of foundation redundancy (in commentary) was
simplified.
• Tables relating resistance factor to site variability were removed from
the specifications and decisions were deferred to the engineer. The
site variability method was retained as an acceptable option to aid in
engineering judgment.
• Precaution for static analysis predictions for piles greater than 24“
was added.
• The resulting changes based on the above was a modest increase
for several resistance factors.
72
5th Edition 2010 Changes Sec 10.7
• Use of dynamic tests with signal matching to estimate side friction
were added as a reasonable alternative to static analysis methods or
load testing.
• Table 10.7.2.4-1, small adjustments in the p-multipliers for group
lateral load analysis.
• Provisions for piles driven to hard rock (Article 10.7.3.2) were made
more complete.
• Article 10.7.3.3 changed to clarify the use and potential pitfalls of the
approaches provided to estimate the pile length required.
• Article C10.7.3.4.3, guidance added regarding the length of time
needed for various soil conditions before a restrike should be
attempted.
73
Table 10.5.5.2.3-1
Resistance Factors for Driven Piles
• Static Load Test with Dynamic Tests – 0.80
(minimum test number 2 and minimum percentage 2% of tests)
• Static Load Test without Dynamic Tests – 0.75
• Dynamic Testing 100% production piles – 0.75
• Dynamic Tests – 0.65 (minimum test number 2 and
minimum percentage 2% of tests)
• Wave Equation – 0.50
74
For More Information on Driven Piles
75
REFERENCES
• Allen, T. M. 2005. “Development of Geotechnical
Resistance Factors and Downdrag Load Factors for LRFD
Foundation Strength Limit State Design”, FHWA-NHI-05052, FHWA, Wash. DC.
• Barker, R. M. et al 1991. “Manuals for the Design of Bridge
Foundations” NCHRP Report 343. Transportation Research
Board, NRC, Wash., DC.
• Hannigan P.J. et al, 2005. “Design and Construction of
Driven Pile Foundations”, FHWA-HI-05, FHWA, Wash. DC
• Paikowsky S. G. et al, 2004. “Load and Resistance Factor
Design (LRFD) for Deep Foundations”, NCHRP Report
507. Transportation Research Board, NRC, Wash. DC.
76
Practical Implementation of LRFD for
Geotechnical Engineering Features
Design and Construction of Driven Pile Foundations
Wednesday, June 22, 2011
PDCA Professors Workshop
By
Jerry A. DiMaggio, PE, D.GE, M. ASCE
E-Mail: [email protected]
77