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By: Mike Muchard, P.E.
Applied Foundation Testing, Inc.
STATNAMIC Load Testing of High Capacity Marine Foundations
AFT
OutlineOutline
St. George Island Project Description St. George Island Project Description Instrumentation of Cylinder PilesInstrumentation of Cylinder Piles STATNAMIC, Static and Dynamic TestingSTATNAMIC, Static and Dynamic Testing Class A Comparison of Test MethodsClass A Comparison of Test Methods
St. George Island BridgeSt. George Island Bridge
Boh Bros. Construction Boh Bros. Construction Co. Inc,Co. Inc,
Sverdrup Civil, Inc. Sverdrup Civil, Inc. 4.1 Miles4.1 Miles 54” Cylinder Piles54” Cylinder Piles 750 to 900 Ton Factored 750 to 900 Ton Factored
Design Loads.Design Loads. Weathered Limestone Weathered Limestone
Bearing MaterialBearing Material
St. George Island BridgeSt. George Island Bridge Load Test Program Load Test Program
6 Non-Production Test Piles6 Non-Production Test Piles All Test Piles Instrumented All Test Piles Instrumented
with multiple levels of Strain with multiple levels of Strain GagesGages
6 STATNAMIC Tests6 STATNAMIC Tests 4 Static Tests4 Static Tests Dynamic Testing on Test Dynamic Testing on Test
Piles and 50 Production PilesPiles and 50 Production Piles Static and Dynamic Tests Static and Dynamic Tests
Performed by Geo Consultant Performed by Geo Consultant
Pile Instrumentation
Post Tensioning StrainsPost Tensioning StrainsPost Tensioning Strain (All Gages)
-300
-250
-200
-150
-100
-50
0
50
0 200 400 600 800 1000 1200 1400 1600 1800 2000
Time (seconds)
Str
ain
(u
e)
Blue1 ue Blue2 ue Blue3 ue
Green1 ue Green2 ue Red1 ue
Red2 ue Red3 ue Yellow1 ue
Yellow2 ue yellow3 ue
Post Tensioning StressPost Tensioning StressPost Tensioning Stress
-1.100
-1.000
-0.900
-0.800
-0.700
-0.600
-0.500
-0.400
-0.300
-0.200
-0.100
0.000
0 200 400 600 800 1000 1200 1400 1600 1800 2000Time (seconds)
Str
ess
(ksi
)
Blue Green Red Yellow
Post Tension MeasurementsPost Tension Measurements54” Cyclinder Pile54” Cyclinder Pile
EccentricityEccentricity– Non-Uniform Contact Between SegementsNon-Uniform Contact Between Segements– ArchingArching
760 to 1,010 psi Pre-stress760 to 1,010 psi Pre-stress Composite Modulus of Elasticity 5,725 ksiComposite Modulus of Elasticity 5,725 ksi Back Calculated f’c over 10,000 psiBack Calculated f’c over 10,000 psi
Pile Driving and Pile Driving and Dynamic TestingDynamic Testing
(PDA)(PDA)
Soil and Foundation ConditionsSoil and Foundation Conditions
Driving MeasurementsDriving MeasurementsForce vs. Time During Pile Driving
-1000
-800
-600
-400
-200
0
200
400
600
800
1000
1200
1400
1600
0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.10 0.11 0.12 0.13 0.14 0.15
Time (Seconds)
Fo
rce
(kip
s)
Level 1 Level 2 Level 3 Level 4 PDA Force
Measurements During DrivingMeasurements During Driving
Stresswave Propagation.Stresswave Propagation. Maximum Tension Occurs Near Pile Top.Maximum Tension Occurs Near Pile Top. Toe Remains In Compression.Toe Remains In Compression. Resistance Not Mobilized Simultaneous. Therefore, Resistance Not Mobilized Simultaneous. Therefore,
Modeling Required for Distribution. Modeling Required for Distribution.
1,600 1,600 Ton Static Ton Static
Load Testing Load Testing
2,000 Ton 2,000 Ton STATNAMIC STATNAMIC
DeviceDevice
Statnamic Test Description
Stages of a STATNAMIC TestStages of a STATNAMIC Test
Before Test The Test After Test
Load Produced F = ma
InstrumentationInstrumentation
RAPID LOADING APPARATUS
LOAD CELL
DISPLACEMENTTRANSDUCER
ACCELEROMETER
SIGNAL CONDITIONING
STORAGE ANDDISPLAY
STATIONARY REFERENCE
PILE FOUNDATION
Load Cell Calibrated Load Cell Calibrated Full ScaleFull Scale
Laser Projector &Laser Projector &Capacitive AccelerometersCapacitive Accelerometers
Data AcquisitionData Acquisition
STATNAMIC AnalysisSTATNAMIC Analysis
Load vs. Displacement from STATNAMIC Test - LT-3
-0.75
-0.70
-0.65
-0.60
-0.55
-0.50
-0.45
-0.40
-0.35
-0.30
-0.25
-0.20
-0.15
-0.10
-0.05
0.00
0 250 500 750 1000 1250 1500 1750 2000 2250 2500 2750 3000 3250 3500 3750 4000
Load (kips)
Dis
pla
ce
me
nt
(in
ch
es
)
Statnamic Applied Load Derived Static Load
STATNAMIC Load DistributionSTATNAMIC Load Distribution
Load vs. Time from STATNAMIC Test - LT-3
-4000
-3500
-3000
-2500
-2000
-1500
-1000
-500
0
0.05 0.10 0.15 0.20 0.25 0.30Time (sec)
Lo
ad
(k
ips
)
Load Cell L 1 L 2 L3 L 4 (Bottom)
Force vs. Time During Pile Driving
-1000
-800
-600
-400
-200
0
200
400
600
800
1000
1200
1400
1600
0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.10 0.11 0.12 0.13 0.14 0.15
Time (Seconds)
Fo
rce
(kip
s)
Level 1 Level 2 Level 3 Level 4 PDA Force
Load vs. Time from STATNAMIC Test - LT-3
-4000
-3500
-3000
-2500
-2000
-1500
-1000
-500
0
0.05 0.10 0.15 0.20 0.25 0.30Time (sec)
Lo
ad
(k
ips
)
Load Cell L 1 L 2 L3 L 4 (Bottom)
Load vs Time from Static Load Test - Test Pile LT-3
-3500
-3000
-2500
-2000
-1500
-1000
-500
0
0 1 2 3 4 5 6Time (hours)
Lo
ad
(k
ips
)
Top L 1 L 2 L 3 L 4 (Bottom)
Three Loading Three Loading
CharacteristicsCharacteristics
STATNAMIC Has Similarities to STATNAMIC Has Similarities to Each Test MethodEach Test Method
Load Duration Precludes StresswavesLoad Duration Precludes Stresswaves Pile displaces as a unit (like a static test)Pile displaces as a unit (like a static test) Much Simpler Analysis Much Simpler Analysis Not an ImpactNot an Impact Rapid Translation, Inertia and Damping must Rapid Translation, Inertia and Damping must
be Subtractedbe Subtracted Rate of Loading Must Also be Considered Rate of Loading Must Also be Considered
Via Rate Factor (Mullins, NCHRP, 2005)Via Rate Factor (Mullins, NCHRP, 2005)
Test Pile 1 - CompositeTest Pile 1 - Composite
Load vs. Displacement from STATNAMIC and STATIC Tests
-3.50
-3.00
-2.50
-2.00
-1.50
-1.00
-0.50
0.00
0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200
Load (kips)
Dis
pla
ce
me
nt
(in
ch
es
)
Static Load Test
Statnamic Load Cycle 1
Statnamic Load Cycle 2
Statnamic Load Cycle 3
Test Pile 1
Test Pile 2 - CompositeTest Pile 2 - Composite
Load vs. Displacement from Statnamic and Static Tests
-0.75
-0.70
-0.65
-0.60
-0.55
-0.50
-0.45
-0.40
-0.35
-0.30
-0.25
-0.20
-0.15
-0.10
-0.05
0.00
0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 3200 3400
Load (kips)
Dis
pla
ce
me
nt
(in
ch
es
)
Statnamic Load Tests
Static Load Test
Test Pile 2
Test Pile 3 - CompositeTest Pile 3 - Composite
Load vs. Displacement from STATNAMIC and STATIC Tests
-0.75
-0.70
-0.65
-0.60
-0.55
-0.50
-0.45
-0.40
-0.35
-0.30
-0.25
-0.20
-0.15
-0.10
-0.05
0.00
0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 3200 3400
Load (kips)
Dis
pla
ce
me
nt
(in
ch
es
)
Statnamic Load Test
Static Load Test
Test Pile 3
Test Pile 5 - CompositeTest Pile 5 - Composite
Load vs. Displacement from Statnamic Test and Static Test
-3.00
-2.50
-2.00
-1.50
-1.00
-0.50
0.00
0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000
Load (kips)
Dis
pla
ce
me
nt
(in
ch
es
) Static Load Test
Statnamic Load Test
Test Pile 5
Pile No.
CAPWAPTotal(kips)
StaticTotal(kips)
STATNAMICTotal(kips)
LT-1 1950 2136 2166
LT-2 2016 3109 3052
LT-3 1820 3060 3113
LT-5 2028 2889 2631
CAPWAP – 14 day Re-strikeSTATNAMIC performed 2 days After Static Test LT-5
CAPWAP / StaticCAPWAP / Static
CAPWAP / Static Comparison
0
500
1000
1500
2000
2500
3000
3500
0 500 1000 1500 2000 2500 3000 3500
Static Load (kips)
CA
WA
P (
kip
s)
Under-Prediction
STATNAMIC / StaticSTATNAMIC / Static
STATNAMIC / Static Comparison
0
500
1000
1500
2000
2500
3000
3500
0 500 1000 1500 2000 2500 3000 3500
Static Load (kips)
Sta
tnam
ic L
oa
d (
kip
s)
Friction ComparisonFriction Comparison
Skin Friction Comparison STATNAMIC AND CAPWAP to Static
0
200
400
600
800
1000
1200
1400
1600
1800
2000
0 200 400 600 800 1000 1200 1400 1600 1800 2000
Static Load (kips)
ST
AT
NA
MIC
/ C
AW
AP
(ki
ps)
STATNAMIC
CAPWAP
End Bearing ComparisonEnd Bearing ComparisonEnd Bearing Comparison
STATNAMIC AND CAPWAP to Static
0
500
1000
1500
2000
2500
3000
3500
0 500 1000 1500 2000 2500 3000 3500
Static Load (kips)
ST
AT
NA
MIC
/ C
AW
AP
(ki
ps)
STATNAMIC
CAPWAP
ConclusionsConclusions
Class A Test Method Comparison. Class A Test Method Comparison. Instrumentation Allowed Measurement of Pre-stress, and Instrumentation Allowed Measurement of Pre-stress, and
Load Distribution During Testing.Load Distribution During Testing. Dynamic Testing Under-predicted Capacity 9% to 41%.Dynamic Testing Under-predicted Capacity 9% to 41%. CAPWAP Skin Friction and End Bearing Predictions had CAPWAP Skin Friction and End Bearing Predictions had
Large Disagreement.Large Disagreement. STATNAMIC within 2% of Static Capacity on Three Piles STATNAMIC within 2% of Static Capacity on Three Piles
and 9% Below in the Fourth Pile. and 9% Below in the Fourth Pile.
AFT
Thank YouAny Questions?
Applied Foundation Testing, Inc.