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Frank Rausche, Garland LikinsFrank Rausche, Garland Likins
2011,2011, Pile Dynamics, Inc.Pile Dynamics, Inc.
GRLWEAP™ FundamentalsFundamentalsGRLWEAP™ FundamentalsFundamentals
CONTENTCONTENTCONTENTCONTENT• Background and TerminologyBackground and Terminology• Wave Equation ModelsWave Equation Models
– Hammer Hammer – Pile Pile – SoilSoil
• The Program FlowThe Program Flow– Bearing graphBearing graph– Inspector’s ChartInspector’s Chart– DriveabilityDriveability
• Background and TerminologyBackground and Terminology• Wave Equation ModelsWave Equation Models
– Hammer Hammer – Pile Pile – SoilSoil
• The Program FlowThe Program Flow– Bearing graphBearing graph– Inspector’s ChartInspector’s Chart– DriveabilityDriveability
1800s1800s Closed Form Solutions & Energy Closed Form Solutions & Energy FormulasFormulas1950:1950: Smith’s Wave EquationSmith’s Wave Equation1970:1970: CAPWAPCAPWAP1976: 1976: WEAP, TTI WEAP, TTI (mainframes)(mainframes)1980s:1980s: GRLWEAPGRLWEAP (PC’s)(PC’s)1986:1986: Hammer Performance StudyHammer Performance Study1996, 2006:1996, 2006: FHWA Manual updatesFHWA Manual updates
1800s1800s Closed Form Solutions & Energy Closed Form Solutions & Energy FormulasFormulas1950:1950: Smith’s Wave EquationSmith’s Wave Equation1970:1970: CAPWAPCAPWAP1976: 1976: WEAP, TTI WEAP, TTI (mainframes)(mainframes)1980s:1980s: GRLWEAPGRLWEAP (PC’s)(PC’s)1986:1986: Hammer Performance StudyHammer Performance Study1996, 2006:1996, 2006: FHWA Manual updatesFHWA Manual updates
Some important developments in Some important developments in Dynamic Pile AnalysisDynamic Pile Analysis
WEAP = Wave Equation Analysis of Piles
WAVE EQUATION OBJECTIVESWAVE EQUATION OBJECTIVESWAVE EQUATION OBJECTIVESWAVE EQUATION OBJECTIVES
• Smith’s Basic Premise: Smith’s Basic Premise: – Replace Energy FormulaReplace Energy Formula– Use improved pile model (elastic pile) Use improved pile model (elastic pile) – Use improved soil model Use improved soil model
(elasto-plastic static with damping)(elasto-plastic static with damping)– Allow for stress calculationsAllow for stress calculations
• Later GRLWEAP improvements:Later GRLWEAP improvements:– realistic Diesel hammer model (thermodynamics)realistic Diesel hammer model (thermodynamics)– comparison with pile top measurementscomparison with pile top measurements– development of more reliable soil constantsdevelopment of more reliable soil constants– driveability and inspectors’ chart optionsdriveability and inspectors’ chart options– residual stress analysis optionresidual stress analysis option
• Smith’s Basic Premise: Smith’s Basic Premise: – Replace Energy FormulaReplace Energy Formula– Use improved pile model (elastic pile) Use improved pile model (elastic pile) – Use improved soil model Use improved soil model
(elasto-plastic static with damping)(elasto-plastic static with damping)– Allow for stress calculationsAllow for stress calculations
• Later GRLWEAP improvements:Later GRLWEAP improvements:– realistic Diesel hammer model (thermodynamics)realistic Diesel hammer model (thermodynamics)– comparison with pile top measurementscomparison with pile top measurements– development of more reliable soil constantsdevelopment of more reliable soil constants– driveability and inspectors’ chart optionsdriveability and inspectors’ chart options– residual stress analysis optionresidual stress analysis option
GRLWEAP ApplicationGRLWEAP ApplicationGRLWEAP ApplicationGRLWEAP Application
• WHEN?WHEN?– Before pile driving beginsBefore pile driving begins– After initial dynamic pile testing ( refined )After initial dynamic pile testing ( refined )
• WHY?WHY?– Equipment selection or qualificationEquipment selection or qualification– Stress determinationStress determination– Formulate driving criterionFormulate driving criterion
• Blow count calculation for desired capacityBlow count calculation for desired capacity– Capacity determination Capacity determination from from
observed blow countobserved blow count
• WHEN?WHEN?– Before pile driving beginsBefore pile driving begins– After initial dynamic pile testing ( refined )After initial dynamic pile testing ( refined )
• WHY?WHY?– Equipment selection or qualificationEquipment selection or qualification– Stress determinationStress determination– Formulate driving criterionFormulate driving criterion
• Blow count calculation for desired capacityBlow count calculation for desired capacity– Capacity determination Capacity determination from from
observed blow countobserved blow count
Some WEAP TerminologySome WEAP TerminologySome WEAP TerminologySome WEAP Terminology• Hammer Hammer Ram plus hammer assemblyRam plus hammer assembly
• Hammer assembly Hammer assembly All non-striking hammer componentsAll non-striking hammer components
• Hammer efficiencyHammer efficiency Ratio of ERatio of Ek k just before impact to Ejust before impact to Epp
• Driving system Driving system All components between hammer and pile topAll components between hammer and pile top
• Helmet weightHelmet weight Weight of driving systemWeight of driving system
• Hammer cushionHammer cushion Protects hammer - between helmet and ramProtects hammer - between helmet and ram
• Pile cushionPile cushion Protects pile - between helmet and pile topProtects pile - between helmet and pile top
• CapCap Generally the striker plate + hammerGenerally the striker plate + hammer cushion+helmetcushion+helmet
• Pile dampingPile damping Damping of pile materialDamping of pile material
• Soil dampingSoil damping Damping of soil in pile-soil interfaceDamping of soil in pile-soil interface
• QuakeQuake Pile displacement when static resistance Pile displacement when static resistance reaches ultimatereaches ultimate
• Hammer Hammer Ram plus hammer assemblyRam plus hammer assembly
• Hammer assembly Hammer assembly All non-striking hammer componentsAll non-striking hammer components
• Hammer efficiencyHammer efficiency Ratio of ERatio of Ek k just before impact to Ejust before impact to Epp
• Driving system Driving system All components between hammer and pile topAll components between hammer and pile top
• Helmet weightHelmet weight Weight of driving systemWeight of driving system
• Hammer cushionHammer cushion Protects hammer - between helmet and ramProtects hammer - between helmet and ram
• Pile cushionPile cushion Protects pile - between helmet and pile topProtects pile - between helmet and pile top
• CapCap Generally the striker plate + hammerGenerally the striker plate + hammer cushion+helmetcushion+helmet
• Pile dampingPile damping Damping of pile materialDamping of pile material
• Soil dampingSoil damping Damping of soil in pile-soil interfaceDamping of soil in pile-soil interface
• QuakeQuake Pile displacement when static resistance Pile displacement when static resistance reaches ultimatereaches ultimate
Some WEAP TerminologySome WEAP TerminologySome WEAP TerminologySome WEAP Terminology
• Bearing Graph Bearing Graph Ult. Capacity and max. stress vs. blow count Ult. Capacity and max. stress vs. blow count for a for a given penetration depthgiven penetration depth
• Inspector’s ChartInspector’s Chart Calculates blow count and stresses Calculates blow count and stresses for given for given ult. ult. capacity at a given penetration depth capacity at a given penetration depth as a function of stroke/energy as a function of stroke/energy
• Driveability analysisDriveability analysis Calculate blow count and stresses Calculate blow count and stresses vs. vs. depth based on static soils analysisdepth based on static soils analysis
• SRDSRD Static Resistance to DrivingStatic Resistance to Driving• Soil set-up factorSoil set-up factor Ratio of long term to EOD resistance Ratio of long term to EOD resistance • Gain/loss factorGain/loss factor Ratio of SRD to long term resistanceRatio of SRD to long term resistance• Variable set-upVariable set-up Setup occurring during a limited driving Setup occurring during a limited driving
interruptioninterruption
• Bearing Graph Bearing Graph Ult. Capacity and max. stress vs. blow count Ult. Capacity and max. stress vs. blow count for a for a given penetration depthgiven penetration depth
• Inspector’s ChartInspector’s Chart Calculates blow count and stresses Calculates blow count and stresses for given for given ult. ult. capacity at a given penetration depth capacity at a given penetration depth as a function of stroke/energy as a function of stroke/energy
• Driveability analysisDriveability analysis Calculate blow count and stresses Calculate blow count and stresses vs. vs. depth based on static soils analysisdepth based on static soils analysis
• SRDSRD Static Resistance to DrivingStatic Resistance to Driving• Soil set-up factorSoil set-up factor Ratio of long term to EOD resistance Ratio of long term to EOD resistance • Gain/loss factorGain/loss factor Ratio of SRD to long term resistanceRatio of SRD to long term resistance• Variable set-upVariable set-up Setup occurring during a limited driving Setup occurring during a limited driving
interruptioninterruption
THE WAVE EQUATION MODELTHE WAVE EQUATION MODELTHE WAVE EQUATION MODELTHE WAVE EQUATION MODEL
• The Wave Equation Analysis calculates the movements (velocities and The Wave Equation Analysis calculates the movements (velocities and displacements) of any point of a slender elastic rod at any time.displacements) of any point of a slender elastic rod at any time.
• The calculation is based on rod The calculation is based on rod – LengthLength– Cross Sectional AreaCross Sectional Area– Elastic ModulusElastic Modulus– Mass densityMass density
• The Wave Equation Analysis calculates the movements (velocities and The Wave Equation Analysis calculates the movements (velocities and displacements) of any point of a slender elastic rod at any time.displacements) of any point of a slender elastic rod at any time.
• The calculation is based on rod The calculation is based on rod – LengthLength– Cross Sectional AreaCross Sectional Area– Elastic ModulusElastic Modulus– Mass densityMass density
GRLWEAP FundamentalsGRLWEAP FundamentalsGRLWEAP FundamentalsGRLWEAP Fundamentals
• For a pile driving analysis, the “rod” is For a pile driving analysis, the “rod” is Hammer + Driving System + PileHammer + Driving System + Pile
• The rod is assumed to be elastic(?) and The rod is assumed to be elastic(?) and slender(?)slender(?)
• The soil is represented by resistance The soil is represented by resistance forces acting at the pile soil interfaceforces acting at the pile soil interface
• For a pile driving analysis, the “rod” is For a pile driving analysis, the “rod” is Hammer + Driving System + PileHammer + Driving System + Pile
• The rod is assumed to be elastic(?) and The rod is assumed to be elastic(?) and slender(?)slender(?)
• The soil is represented by resistance The soil is represented by resistance forces acting at the pile soil interfaceforces acting at the pile soil interface
GRLWEAP - 3 Hammer ModelsGRLWEAP - 3 Hammer Models GRLWEAP - 3 Hammer ModelsGRLWEAP - 3 Hammer Models
Ram: A, L for stiffness, massRam: A, L for stiffness, mass
Cylinder and upper frame = Cylinder and upper frame = assembly top massassembly top mass
Drop heightDrop height
External Combustion Hammer ModelingExternal Combustion Hammer ModelingExternal Combustion Hammer ModelingExternal Combustion Hammer Modeling
Ram guides for assembly stiffnessRam guides for assembly stiffness
Hammer base = Hammer base = assembly bottom mass assembly bottom mass
External Combustion HammersExternal Combustion HammersRam ModelRam Model
External Combustion HammersExternal Combustion HammersRam ModelRam Model
Ram segments Ram segments ~1m long~1m long
Ram segments Ram segments ~1m long~1m long
Combined Ram-Combined Ram-H.CushionH.Cushion
Helmet massHelmet mass
Combined Ram-Combined Ram-H.CushionH.Cushion
Helmet massHelmet mass
External Combustion HammersExternal Combustion HammersCombined Ram Assembly ModelCombined Ram Assembly Model
External Combustion HammersExternal Combustion HammersCombined Ram Assembly ModelCombined Ram Assembly Model
Combined Ram-Combined Ram-H.CushionH.Cushion
Helmet massHelmet mass
Combined Ram-Combined Ram-H.CushionH.Cushion
Helmet massHelmet mass
Ram segments Ram segments
Assembly segmentsAssembly segments
Ram segments Ram segments
Assembly segmentsAssembly segments
Diesel Hammer Combustion Pressure ModelDiesel Hammer Combustion Pressure ModelDiesel Hammer Combustion Pressure ModelDiesel Hammer Combustion Pressure Model
Precompression-Precompression-Combustion-Combustion-Expansion- Expansion-
pressures from pressures from thermodynamicsthermodynamics
Precompression-Precompression-Combustion-Combustion-Expansion- Expansion-
pressures from pressures from thermodynamicsthermodynamics
PortsPortsPortsPorts
• Compressive Stroke, Compressive Stroke, hhCC
• Cylinder Area, Cylinder Area, AACHCH
• Final Chamber Volume, Final Chamber Volume, VVCHCH
• Max. Pressure, pMax. Pressure, pMAXMAX
• Compressive Stroke, Compressive Stroke, hhCC
• Cylinder Area, Cylinder Area, AACHCH
• Final Chamber Volume, Final Chamber Volume, VVCHCH
• Max. Pressure, pMax. Pressure, pMAXMAX
hhCChhCC
DIESEL PRESSURE MODELDIESEL PRESSURE MODELLiquid Injection HammersLiquid Injection Hammers
DIESEL PRESSURE MODELDIESEL PRESSURE MODELLiquid Injection HammersLiquid Injection Hammers
TimeTimeTimeTime
PressurePressure
ppMAXMAX
Po
rt
Po
rt
Op
en
Op
en
Po
rt
Po
rt
Op
en
Op
en
Po
rt C
losu
reP
ort
Clo
sure
Po
rt C
losu
reP
ort
Clo
sure
Imp
act
Imp
act
Imp
act
Imp
act
CompressionCompressionCompressionCompression
ExpansionExpansionExpansionExpansion
Co
mb
ust
ion
Co
mb
ust
ion
Co
mb
ust
ion
Co
mb
ust
ion
Downward = Downward = upward strokeupward stroke
Downward = Downward = upward strokeupward stroke
Program Flow – Diesel HammersProgram Flow – Diesel HammersFixed pressure, variable strokeFixed pressure, variable stroke
Program Flow – Diesel HammersProgram Flow – Diesel HammersFixed pressure, variable strokeFixed pressure, variable stroke
Downward = Downward = rated strokerated stroke
Downward = Downward = rated strokerated stroke
Calculate pile andCalculate pile and ram motionram motion
Calculate pile andCalculate pile and ram motionram motion
Find upward Find upward stroke stroke
Find upward Find upward stroke stroke
Output Output Output Output
Strokes Strokes match?match?
Strokes Strokes match?match?
Setup hammer,Setup hammer,pile, soil model pile, soil model
Setup hammer,Setup hammer,pile, soil model pile, soil model
Next Ru? Next Ru? Next Ru? Next Ru?
NN
NN
Potential / Kinetic EnergyPotential / Kinetic EnergyPotential / Kinetic EnergyPotential / Kinetic Energy
WWPP
WWRR
hh
EEPP = W = WRR h h (potential or rated energy)(potential or rated energy)
WWRR vvii
EEK K = = ηηEEPP ( (ηη - hammer efficiency) - hammer efficiency)
vvii = = 2g h 2g h ηη
EEKK = ½ m = ½ mRR v vii22 ((kinetic energykinetic energy))
Max EMax ETT = ∫F(t) v(t) dt = ∫F(t) v(t) dt
“ “Transferred Energy”Transferred Energy” EMXEMX
ETR = ETR = EMX/ EEMX/ ERR = = “transfer ratio”“transfer ratio”
GRLWEAP hammer efficienciesGRLWEAP hammer efficienciesGRLWEAP hammer efficienciesGRLWEAP hammer efficiencies
•The hammer efficiency reduces the The hammer efficiency reduces the impact velocity of the ram; impact velocity of the ram; reduction reduction factor is based on experiencefactor is based on experience•Hammer efficiencies cover all losses Hammer efficiencies cover all losses which cannot be calculatedwhich cannot be calculated•Diesel hammer energy loss due to Diesel hammer energy loss due to precompression or cushioning can be precompression or cushioning can be calculated and, therefore, is not covered calculated and, therefore, is not covered by hammer efficiencyby hammer efficiency
GRLWEAP diesel hammer efficienciesGRLWEAP diesel hammer efficienciesGRLWEAP diesel hammer efficienciesGRLWEAP diesel hammer efficiencies
Open end diesel hammers:Open end diesel hammers: 0.800.80(uncertainty of fall height, (uncertainty of fall height, frictionfriction, alignment), alignment)
Closed end diesel hammers:Closed end diesel hammers: 0.800.80(uncertainty of fall height, (uncertainty of fall height, frictionfriction, power assist, , power assist, alignment)alignment)
Other ECH efficiency recommendationsOther ECH efficiency recommendationsOther ECH efficiency recommendationsOther ECH efficiency recommendations
Single acting Air/Steam hammers:Single acting Air/Steam hammers: 0.670.67(fall height, (fall height, preadmissionpreadmission, , frictionfriction, alignment), alignment)
Double acting Air/Steam/Hydraulic:Double acting Air/Steam/Hydraulic: 0.500.50((preadmission, reduced pressure, frictionpreadmission, reduced pressure, friction, alignment), alignment)
Drop hammers winch released:Drop hammers winch released: 0.500.50(uncertainty of fall height, (uncertainty of fall height, frictionfriction, and , and winch losseswinch losses))
Free released drop hammers (rare):Free released drop hammers (rare): 0.670.67 (uncertainty of fall height friction) (uncertainty of fall height friction)
GRLWEAP hydraulic hammer GRLWEAP hydraulic hammer efficienciesefficiencies
GRLWEAP hydraulic hammer GRLWEAP hydraulic hammer efficienciesefficiencies
Hammers with internal monitor:Hammers with internal monitor: 0.950.95(uncertainty of hammer alignment)(uncertainty of hammer alignment)
Hydraulic hammers (no monitor):Hydraulic hammers (no monitor): 0.800.80
Power assisted hydraulic hammers:Power assisted hydraulic hammers: 0.800.80(uncertainty of fall height, alignment, friction, power assist) (uncertainty of fall height, alignment, friction, power assist)
If not measured, fall height must be assumed and can be quite variable – be cautious !
VIBRATORY HAMMER MODELVIBRATORY HAMMER MODELVIBRATORY HAMMER MODELVIBRATORY HAMMER MODEL
2-mass system with vibratory force2-mass system with vibratory force
FFV V = m= mee 2 2 rre e sinsint t
FFV V = m= mee [ω [ω22rreesinωt - sinωt - 22(t)](t)]
2-mass system with vibratory force2-mass system with vibratory force
FFV V = m= mee 2 2 rre e sinsint t
FFV V = m= mee [ω [ω22rreesinωt - sinωt - 22(t)](t)]
FFLLFFLL
FFVVFFVV
mm11mm11
mm22mm22
Bias Mass with Line ForceBias Mass with Line ForceBias Mass with Line ForceBias Mass with Line Force
Connecting Pads Connecting Pads Connecting Pads Connecting Pads
Oscillator with eccentric Oscillator with eccentric masses, mmasses, mee, radii, r, radii, ree and and
clampclamp
Oscillator with eccentric Oscillator with eccentric masses, mmasses, mee, radii, r, radii, ree and and
clampclamp
Pile:Pile:
Masses and Masses and SpringsSprings
Pile:Pile:
Masses and Masses and SpringsSprings
Soil:Soil:
Elasto-Plastic Elasto-Plastic Springs and Springs and
DashpotsDashpots
Soil:Soil:
Elasto-Plastic Elasto-Plastic Springs and Springs and
DashpotsDashpots
Hammer:Hammer:
(Masses and (Masses and Springs)Springs)
Hammer:Hammer:
(Masses and (Masses and Springs)Springs)
Driving System: Driving System: Cushions (Springs)Cushions (Springs)Helmet (Mass)Helmet (Mass)
Driving System: Driving System: Cushions (Springs)Cushions (Springs)Helmet (Mass)Helmet (Mass)
Hammer-Driving System-Pile-Soil ModelHammer-Driving System-Pile-Soil Model
Driving System ModelingDriving System ModelingDriving System ModelingDriving System ModelingThe Driving Systems Consists ofThe Driving Systems Consists of
– Helmet including inserts to align hammer and pileHelmet including inserts to align hammer and pile– Hammer Cushion to protect hammerHammer Cushion to protect hammer– Pile Cushion to protect concrete pilesPile Cushion to protect concrete piles
The Driving Systems Consists ofThe Driving Systems Consists of– Helmet including inserts to align hammer and pileHelmet including inserts to align hammer and pile– Hammer Cushion to protect hammerHammer Cushion to protect hammer– Pile Cushion to protect concrete pilesPile Cushion to protect concrete piles
GRLWEAP Driving System HelpGRLWEAP Driving System HelpGRLWEAP Driving System HelpGRLWEAP Driving System Help
GRLWEAP Driving System HelpGRLWEAP Driving System HelpGRLWEAP Driving System HelpGRLWEAP Driving System Help
GRLWEAP Pile ModelGRLWEAP Pile ModelGRLWEAP Pile ModelGRLWEAP Pile Model
To make realistic calculations possible• The pile is divided into N segments
– of approximate length ∆L = 1 m (3.3 ft)– with mass m = ρ A ∆L – and stiffness k = E A / ∆L– there are N = L / ∆L pile segments
• Divide time into intervals (typically 0.1 ms)
To make realistic calculations possible• The pile is divided into N segments
– of approximate length ∆L = 1 m (3.3 ft)– with mass m = ρ A ∆L – and stiffness k = E A / ∆L– there are N = L / ∆L pile segments
• Divide time into intervals (typically 0.1 ms)
Computational Time Increment, Computational Time Increment, ∆∆ttComputational Time Increment, Computational Time Increment, ∆∆tt∆∆t is a fraction (e.g. ½ ) of the critical time, which is t is a fraction (e.g. ½ ) of the critical time, which is ∆∆L/cL/c∆∆t is a fraction (e.g. ½ ) of the critical time, which is t is a fraction (e.g. ½ ) of the critical time, which is ∆∆L/cL/c
∆ttcrcr
∆LL
L/cL/c
∆t
TimeTime
LengthLength
Driving system Driving system model model
(Concrete piles)(Concrete piles)
Driving system Driving system model model
(Concrete piles)(Concrete piles)
Pile Cushion + Pile Top: Pile Cushion + Pile Top: Spring + DashpotSpring + Dashpot
Pile Cushion + Pile Top: Pile Cushion + Pile Top: Spring + DashpotSpring + Dashpot
Helmet + InsertsHelmet + InsertsHelmet + InsertsHelmet + Inserts
Hammer Cushion: Spring Hammer Cushion: Spring plus Dashpotplus Dashpot
Hammer Cushion: Spring Hammer Cushion: Spring plus Dashpotplus Dashpot
Non-linear springsNon-linear springsSprings at material interfacesSprings at material interfaces
Non-linear springsNon-linear springsSprings at material interfacesSprings at material interfaces
Hammer interface springsHammer interface springs
CushionsCushions
Helmet/PileHelmet/Pile
Splices with slacksSplices with slacks
Hammer interface springsHammer interface springs
CushionsCushions
Helmet/PileHelmet/Pile
Splices with slacksSplices with slacks
Non-linear (cushion) springsNon-linear (cushion) springsNon-linear (cushion) springsNon-linear (cushion) springs
• ParametersParameters• Stiffness, k = EA/tStiffness, k = EA/t• Coefficient of Restitution, CORCoefficient of Restitution, COR
• Round-out deformation,Round-out deformation,δδr r , or , or
compressive slackcompressive slack
• Tension slack, Tension slack, δδss
• ParametersParameters• Stiffness, k = EA/tStiffness, k = EA/t• Coefficient of Restitution, CORCoefficient of Restitution, COR
• Round-out deformation,Round-out deformation,δδr r , or , or
compressive slackcompressive slack
• Tension slack, Tension slack, δδss
δδrrδδrr
k /k /CORCOR22k /k /CORCOR22kk
δδssδδssCompressive Compressive DeformationDeformation
Compressive Compressive DeformationDeformation
Compressive Compressive ForceForceCompressive Compressive ForceForce
MaterialMaterial Modulus Modulus (ksi)(ksi)
Aluminum Aluminum MicartaMicarta
350350
ConbestConbest 280280
HamortexHamortex 125125
NylonNylon 175-200175-200
MaterialMaterial Modulus Modulus (ksi)(ksi)
PlywoodPlywood 30 new 30 new 75 used75 used
Oak Oak (transverse)(transverse)
6060
Oak Oak (parallel)(parallel)
750750
Hammer cushion Pile cushionHammer cushion Pile cushionHammer cushion Pile cushionHammer cushion Pile cushion
∆∆L= L/N L= L/N 1m 1m
Mass density, Mass density, Modulus, EModulus, EX-Area, AX-Area, A
Spring (static resistance)Spring (static resistance)Dashpot (dynamic resist)Dashpot (dynamic resist)Mass mMass mi i Stiffness kStiffness kii
The Pile and Soil ModelThe Pile and Soil ModelThe Pile and Soil ModelThe Pile and Soil Model
Soil ResistanceSoil ResistanceSoil ResistanceSoil Resistance
• Soil resistance slows pile movement and causes pile reboundSoil resistance slows pile movement and causes pile rebound• A very slowly moving pile only encounters static resistanceA very slowly moving pile only encounters static resistance• A rapidly moving pile also encounters dynamic resistanceA rapidly moving pile also encounters dynamic resistance• The static resistance to driving may differ from the soil The static resistance to driving may differ from the soil
resistance under static loadsresistance under static loads– Pore pressure effectsPore pressure effects– Lateral movementsLateral movements– Plugging for open profilesPlugging for open profiles– Etc.Etc.
• Soil resistance slows pile movement and causes pile reboundSoil resistance slows pile movement and causes pile rebound• A very slowly moving pile only encounters static resistanceA very slowly moving pile only encounters static resistance• A rapidly moving pile also encounters dynamic resistanceA rapidly moving pile also encounters dynamic resistance• The static resistance to driving may differ from the soil The static resistance to driving may differ from the soil
resistance under static loadsresistance under static loads– Pore pressure effectsPore pressure effects– Lateral movementsLateral movements– Plugging for open profilesPlugging for open profiles– Etc.Etc.
The Soil ModelThe Soil ModelThe Soil ModelThe Soil Model
Segment Segment
i-1i-1
Segment Segment
ii
kki-1i-1,R,Rui-1ui-1
JJi-1i-1
Segment Segment
i+1 i+1
kkii,R,Ruiui
JJii
kki+1i+1,R,Rui+1ui+1
JJi+1i+1
RIGID SOIL RIGID SOIL SURROUNDINGSURROUNDINGSOIL/PILE SOIL/PILE INTERFACEINTERFACE
RIGID SOIL RIGID SOIL SURROUNDINGSURROUNDINGSOIL/PILE SOIL/PILE INTERFACEINTERFACE
Smith’s Soil ModelSmith’s Soil ModelSmith’s Soil ModelSmith’s Soil Model
Total Soil ResistanceTotal Soil ResistanceRRtotaltotal = R = Rsisi +R +Rdidi
SegmentSegment
ii
uuii
vvii
FixedFixed
Shaft Resistance and QuakeShaft Resistance and QuakeShaft Resistance and QuakeShaft Resistance and Quake
qqii
RRuiui
qqii
RRsisi
uuii
-R-Ruiui
Recommended Shaft Quake Recommended Shaft Quake ( ( qqi i ))
2.5 mm; 0.1 inches2.5 mm; 0.1 inches
Recommended Toe Quakes, qRecommended Toe Quakes, qttRecommended Toe Quakes, qRecommended Toe Quakes, qtt
0.1” or 2.5 mm0.1” or 2.5 mm
0.04” or 1 mm on 0.04” or 1 mm on hard rockhard rock
qqtt
RRqqttRRutut
uu
D/120: very dense/hard D/120: very dense/hard soilssoils
D/60: softer/loose soilsD/60: softer/loose soils
Displacement pilesDisplacement pilesNon-displacement Non-displacement pilespiles
DD
Smith’s Soil Damping Model (Shaft or Toe)Smith’s Soil Damping Model (Shaft or Toe)Smith’s Soil Damping Model (Shaft or Toe)Smith’s Soil Damping Model (Shaft or Toe)
PilePileSegmentSegment
Smith damping factor,Smith damping factor,JJs s [s/m or s/ft][s/m or s/ft]
RRdd = R = RssJJss v v
Fixed Fixed reference reference (soil around (soil around pile)pile)
velocity vvelocity v
RRdd = R = RuuJJss v v
Smith-viscous damping Smith-viscous damping factor Jfactor Jsvi svi [s/m or s/ft][s/m or s/ft]
dashpotdashpot
Alternative Soil Models Coyle-Gibson Results (1968)
Alternative Soil Models Coyle-Gibson Results (1968)
SandSand ClayClay
Recommended damping factorsRecommended damping factorsafter Smithafter Smith
Recommended damping factorsRecommended damping factorsafter Smithafter Smith
ShaftShaft
Clay:Clay: 0.65 s/m0.65 s/m or 0.20 s/ftor 0.20 s/ft
Sand:Sand: 0.16 s/m or 0.05 s/ft0.16 s/m or 0.05 s/ft
Silts:Silts: use an intermediate valueuse an intermediate value
Layered soils: Layered soils: use a weighted average use a weighted average
ShaftShaft
Clay:Clay: 0.65 s/m0.65 s/m or 0.20 s/ftor 0.20 s/ft
Sand:Sand: 0.16 s/m or 0.05 s/ft0.16 s/m or 0.05 s/ft
Silts:Silts: use an intermediate valueuse an intermediate value
Layered soils: Layered soils: use a weighted average use a weighted average
ToeAll soils: 0.50 s/m or 0.15 s/ft
Numerical treatment:Numerical treatment:Force balance at a segmentForce balance at a segment
Numerical treatment:Numerical treatment:Force balance at a segmentForce balance at a segment
Acceleration: aAcceleration: aii == ((FFi i – F – Fi+1i+1 ++ WWii – – RRii) / ) / mmii
Velocity, vVelocity, vii, and Displacement, u, and Displacement, uii, from Integration, from Integration
Acceleration: aAcceleration: aii == ((FFi i – F – Fi+1i+1 ++ WWii – – RRii) / ) / mmii
Velocity, vVelocity, vii, and Displacement, u, and Displacement, uii, from Integration, from Integration
Mass mMass mii
Force from upper spring, FForce from upper spring, FiiForce from upper spring, FForce from upper spring, Fii
Force from lower spring, FForce from lower spring, Fi+1i+1Force from lower spring, FForce from lower spring, Fi+1i+1
Resistance force, RResistance force, Ri i
(static plus damping)(static plus damping)
Resistance force, RResistance force, Ri i
(static plus damping)(static plus damping)
Weight, WWeight, WiiWeight, WWeight, Wii
Calculate displacements:Calculate displacements:
uuni ni = u= uoi oi + v+ voioi t t
Calculate spring displacement:Calculate spring displacement: c cii = u = unini
- u - uni-1ni-1
Calculate spring forcesCalculate spring forces::
FFii = k = kii c cii
k = EA / k = EA / ΔΔLL
Calculate displacements:Calculate displacements:
uuni ni = u= uoi oi + v+ voioi t t
Calculate spring displacement:Calculate spring displacement: c cii = u = unini
- u - uni-1ni-1
Calculate spring forcesCalculate spring forces::
FFii = k = kii c cii
k = EA / k = EA / ΔΔLL
uuni-1ni-1
mmi i
mmi+1 i+1
mmi-1 i-1
uunini
uuni+1ni+1
FFii, c, ciiFFii, c, cii
Wave Equation Analysis calculates displacement of Wave Equation Analysis calculates displacement of all points of a pile as function of time.all points of a pile as function of time.
Wave Equation Analysis calculates displacement of Wave Equation Analysis calculates displacement of all points of a pile as function of time.all points of a pile as function of time.
Set or Blow Count Calculation from Set or Blow Count Calculation from Extrapolated toe displacementExtrapolated toe displacement
Set or Blow Count Calculation from Set or Blow Count Calculation from Extrapolated toe displacementExtrapolated toe displacement
RRRR
SetSetSetSetFinal SetFinal SetFinal SetFinal Set
Maximum SetMaximum SetMaximum SetMaximum Set
QuakeQuakeQuakeQuake
RRuuRRuu
ExtrapolatedExtrapolatedExtrapolatedExtrapolated
CalculatedCalculatedCalculatedCalculated
Blow Count CalculationBlow Count CalculationBlow Count CalculationBlow Count Calculation
• Once pile toe rebounds, Once pile toe rebounds, max toe max toe displacement is known, displacement is known, example: 0.3 inchexample: 0.3 inch or 7.5 mm or 7.5 mm
• Final SetFinal Set = Max Toe Displacement – Quake = Max Toe Displacement – Quake = = 0.3 – 0.1 0.3 – 0.1 == 0.2 inch0.2 inch
= 7.5 - 2.5 = 7.5 - 2.5 = 5 mm= 5 mm• ““Blow Count” is Inverse of “Final Set”Blow Count” is Inverse of “Final Set”
BCT = 12 / 0.2 BCT = 12 / 0.2 = 60 Bl / ft= 60 Bl / ft BCT = 1000 / 5 BCT = 1000 / 5 = 200 Bl / m= 200 Bl / m
• Once pile toe rebounds, Once pile toe rebounds, max toe max toe displacement is known, displacement is known, example: 0.3 inchexample: 0.3 inch or 7.5 mm or 7.5 mm
• Final SetFinal Set = Max Toe Displacement – Quake = Max Toe Displacement – Quake = = 0.3 – 0.1 0.3 – 0.1 == 0.2 inch0.2 inch
= 7.5 - 2.5 = 7.5 - 2.5 = 5 mm= 5 mm• ““Blow Count” is Inverse of “Final Set”Blow Count” is Inverse of “Final Set”
BCT = 12 / 0.2 BCT = 12 / 0.2 = 60 Bl / ft= 60 Bl / ft BCT = 1000 / 5 BCT = 1000 / 5 = 200 Bl / m= 200 Bl / m
Alternative Blow Count CalculationAlternative Blow Count Calculationby RSAby RSA
Alternative Blow Count CalculationAlternative Blow Count Calculationby RSAby RSA
• Residual Stress Analysis is also called Residual Stress Analysis is also called Multiple Blow AnalysisMultiple Blow Analysis
• Analyzes several blows consecutively with Analyzes several blows consecutively with initial stresses, displacements from static initial stresses, displacements from static state at end of previous blowstate at end of previous blow
• Yields residual stresses in pile at end of Yields residual stresses in pile at end of blow; generally lower blow countsblow; generally lower blow counts
• Residual Stress Analysis is also called Residual Stress Analysis is also called Multiple Blow AnalysisMultiple Blow Analysis
• Analyzes several blows consecutively with Analyzes several blows consecutively with initial stresses, displacements from static initial stresses, displacements from static state at end of previous blowstate at end of previous blow
• Yields residual stresses in pile at end of Yields residual stresses in pile at end of blow; generally lower blow countsblow; generally lower blow counts
RESIDUAL STRESS OPTIONRESIDUAL STRESS OPTIONRESIDUAL STRESS OPTIONRESIDUAL STRESS OPTIONBETWEEN HAMMER BLOWS, PILE AND SOIL STORE ENERGYBETWEEN HAMMER BLOWS, PILE AND SOIL STORE ENERGYBETWEEN HAMMER BLOWS, PILE AND SOIL STORE ENERGYBETWEEN HAMMER BLOWS, PILE AND SOIL STORE ENERGY
Set for 2 BlowsSet for 2 Blows
Convergence:Convergence:Consecutive Blows Consecutive Blows
have same have same pile compression/setspile compression/sets
COMPUTATIONAL PROCEDURECOMPUTATIONAL PROCEDURE
Smith’s Bearing GraphSmith’s Bearing GraphCOMPUTATIONAL PROCEDURECOMPUTATIONAL PROCEDURE
Smith’s Bearing GraphSmith’s Bearing Graph
• Analyze for a range of capacitiesAnalyze for a range of capacities– In: Static resistance distribution assumedIn: Static resistance distribution assumed– Out: Pile static capacity vs. blow countOut: Pile static capacity vs. blow count– Out: Critical driving stresses vs. blow countOut: Critical driving stresses vs. blow count– Out: Stroke for diesel hammers vs. blow countOut: Stroke for diesel hammers vs. blow count
• Analyze for a range of capacitiesAnalyze for a range of capacities– In: Static resistance distribution assumedIn: Static resistance distribution assumed– Out: Pile static capacity vs. blow countOut: Pile static capacity vs. blow count– Out: Critical driving stresses vs. blow countOut: Critical driving stresses vs. blow count– Out: Stroke for diesel hammers vs. blow countOut: Stroke for diesel hammers vs. blow count
Bearing Graph: Bearing Graph: Required Blow CountRequired Blow Count
Bearing Graph: Bearing Graph: Required Blow CountRequired Blow Count
For required capacityFor required capacity
Find minimum blow countFind minimum blow count
Bearing Graph: Bearing Graph: Capacity DeterminationCapacity Determination
Bearing Graph: Bearing Graph: Capacity DeterminationCapacity Determination
Find indicated capacityFind indicated capacity
For For observedobserved blow count blow countFor For observedobserved blow count blow count
Static AnalysisStatic AnalysisRam velocityRam velocity
Static AnalysisStatic AnalysisRam velocityRam velocity
Program Flow – Bearing GraphProgram Flow – Bearing GraphProgram Flow – Bearing GraphProgram Flow – Bearing Graph
Model hammer &Model hammer &driving systemdriving system
Model hammer &Model hammer &driving systemdriving system
Model PileModel PileModel PileModel Pile Dynamic AnalysisDynamic Analysis• Pile stressesPile stresses• Energy transferEnergy transfer• Pile velocitiesPile velocities
Dynamic AnalysisDynamic Analysis• Pile stressesPile stresses• Energy transferEnergy transfer• Pile velocitiesPile velocities
Choose first Ru Choose first Ru Choose first Ru Choose first Ru Calculate BlowCalculate Blow
CountCount
Calculate BlowCalculate BlowCountCount
Distribute RuDistribute RuSet Soil ConstantsSet Soil ConstantsTime IncrementTime Increment
Distribute RuDistribute RuSet Soil ConstantsSet Soil ConstantsTime IncrementTime Increment
Output Output Output Output
IncreaseIncrease RRuu??
IncreaseIncrease RRuu??
Increase Ru Increase Ru Increase Ru Increase Ru InputInput InputInput
NN
PURPOSE OF ANALYSISPURPOSE OF ANALYSISPURPOSE OF ANALYSISPURPOSE OF ANALYSIS
• Preliminary Equipment SelectionPreliminary Equipment Selection– Hammer OK for Pile, CapacityHammer OK for Pile, Capacity– Includes stress checkIncludes stress check
• Driving CriterionDriving Criterion– Blow Count for Capacity and StrokeBlow Count for Capacity and Stroke
• Preliminary Equipment SelectionPreliminary Equipment Selection– Hammer OK for Pile, CapacityHammer OK for Pile, Capacity– Includes stress checkIncludes stress check
• Driving CriterionDriving Criterion– Blow Count for Capacity and StrokeBlow Count for Capacity and Stroke
OUTPUT REVIEWOUTPUT REVIEWOUTPUT REVIEWOUTPUT REVIEW
• Blow Counts Satisfactory?Blow Counts Satisfactory?
• Stresses Less Than Allowable?Stresses Less Than Allowable?
• Economical Hammer, Pile?Economical Hammer, Pile?
If not, consider reanalyzing with different If not, consider reanalyzing with different hammer system, pile size.hammer system, pile size.
• Blow Counts Satisfactory?Blow Counts Satisfactory?
• Stresses Less Than Allowable?Stresses Less Than Allowable?
• Economical Hammer, Pile?Economical Hammer, Pile?
If not, consider reanalyzing with different If not, consider reanalyzing with different hammer system, pile size.hammer system, pile size.
OKOK
BadBad
INSPECTOR’S CHARTINSPECTOR’S CHARTConstant capacity – analyze with variable energy or strokeConstant capacity – analyze with variable energy or stroke
Question for Driveability:Question for Driveability:WHAT IS RWHAT IS RUU DURING DRIVING? DURING DRIVING?
Question for Driveability:Question for Driveability:WHAT IS RWHAT IS RUU DURING DRIVING? DURING DRIVING?
• We call it Static Resistance to Driving (SRD), We call it Static Resistance to Driving (SRD),
because we lose shaft resistance during driving.because we lose shaft resistance during driving.
• Will we regain resistance by Will we regain resistance by Soil Set-upSoil Set-up
primarily along shaft (may be 10 x in clay)primarily along shaft (may be 10 x in clay)
• Driveability requires analyze with full loss of Driveability requires analyze with full loss of
set-up (or with partial loss of set-up for a short set-up (or with partial loss of set-up for a short
driving interruption)driving interruption)
• We call it Static Resistance to Driving (SRD), We call it Static Resistance to Driving (SRD),
because we lose shaft resistance during driving.because we lose shaft resistance during driving.
• Will we regain resistance by Will we regain resistance by Soil Set-upSoil Set-up
primarily along shaft (may be 10 x in clay)primarily along shaft (may be 10 x in clay)
• Driveability requires analyze with full loss of Driveability requires analyze with full loss of
set-up (or with partial loss of set-up for a short set-up (or with partial loss of set-up for a short
driving interruption)driving interruption)
Set-up factorsSet-up factorsSet-up factorsSet-up factors
Soil Type Setup Factor
Clay 2
Silt – Clay 1
Silt 1.5
Sand – Clay 1.2
Fine Sand 1
Sand - Gravel 1
Thendean, G., Rausche, F., Svinkin, M., Likins, G. E., September, 1996. Wave Equation Correlation Studies. Proceedings of the Fifth International Conference on the Application of Stress-wave Theory to Piles 1996: Orlando, FL; 144-162.
RuRu
Ru/SFRu/SF
DrivingDriving
Time Time
Set-up TimeSet-up Time
Waiting TimeWaiting Time
Remolding Remolding energyenergy
Re-DriveRe-Drive
Ru/SFRu/SF
• Set-up factor, SFSet-up factor, SF
For Driveability:For Driveability:Static capacity changesStatic capacity changes
For Driveability:For Driveability:Static capacity changesStatic capacity changes
• Capacity increases (Set-up) after driving stopsCapacity increases (Set-up) after driving stops• Capacity decreases (Remolds) during redriveCapacity decreases (Remolds) during redrive
Analysis Analysis Analysis Analysis
Program Flow – DriveabilityProgram Flow – DriveabilityProgram Flow – DriveabilityProgram Flow – Driveability
Model hammer &Model hammer &driving systemdriving system
Model hammer &Model hammer &driving systemdriving system
First depth of First depth of analysis analysis
- soil model -- soil model -
First depth of First depth of analysis analysis
- soil model -- soil model -
Next G/LNext G/L Next G/LNext G/L
Pile length and Pile length and modelmodel
Pile length and Pile length and modelmodel
Calculate Ru Calculate Ru for first gain/lossfor first gain/loss
Calculate Ru Calculate Ru for first gain/lossfor first gain/loss
Output Output Output Output IncreaseIncrease Depth?Depth?
IncreaseIncrease Depth?Depth?
Increase Depth Increase Depth Increase Depth Increase Depth
InputInput InputInput
IncreaseIncrease G/L?G/L?
IncreaseIncrease G/L?G/L?
NN
NN
COMPUTATIONAL PROCEDURECOMPUTATIONAL PROCEDURE
Driveability AnalysisDriveability AnalysisCOMPUTATIONAL PROCEDURECOMPUTATIONAL PROCEDURE
Driveability AnalysisDriveability Analysis
• Analysis as the pile is penetratedAnalysis as the pile is penetrated– Input capacity with depth (static analysis)Input capacity with depth (static analysis)
• Generates a driving recordGenerates a driving record– Predicts blow count with depthPredicts blow count with depth– Stresses, (diesel stroke), with depthStresses, (diesel stroke), with depth
• Analysis as the pile is penetratedAnalysis as the pile is penetrated– Input capacity with depth (static analysis)Input capacity with depth (static analysis)
• Generates a driving recordGenerates a driving record– Predicts blow count with depthPredicts blow count with depth– Stresses, (diesel stroke), with depthStresses, (diesel stroke), with depth
Static Soil AnalysisStatic Soil AnalysisStatic Soil AnalysisStatic Soil Analysis
Approximate for Bearing Graph:Approximate for Bearing Graph:– Percent Shaft ResistancePercent Shaft Resistance– Resistance DistributionResistance Distribution
Detailed for DriveabilityDetailed for Driveability– Shaft Resistance Shaft Resistance vsvs Depth Depth– End Bearing End Bearing vsvs Depth Depth– Set-up FactorSet-up Factor
Approximate for Bearing Graph:Approximate for Bearing Graph:– Percent Shaft ResistancePercent Shaft Resistance– Resistance DistributionResistance Distribution
Detailed for DriveabilityDetailed for Driveability– Shaft Resistance Shaft Resistance vsvs Depth Depth– End Bearing End Bearing vsvs Depth Depth– Set-up FactorSet-up Factor
PURPOSE OF ANALYSISPURPOSE OF ANALYSISPURPOSE OF ANALYSISPURPOSE OF ANALYSIS
• Preliminary Equipment SelectionPreliminary Equipment Selection– Hammer OK for Pile, CapacityHammer OK for Pile, Capacity
• Driving CriterionDriving Criterion– Blow Count for Capacity and strokeBlow Count for Capacity and stroke
• DriveabilityDriveability– Acceptable Blow Count throughout Acceptable Blow Count throughout – Acceptable Stresses throughoutAcceptable Stresses throughout
• Preliminary Equipment SelectionPreliminary Equipment Selection– Hammer OK for Pile, CapacityHammer OK for Pile, Capacity
• Driving CriterionDriving Criterion– Blow Count for Capacity and strokeBlow Count for Capacity and stroke
• DriveabilityDriveability– Acceptable Blow Count throughout Acceptable Blow Count throughout – Acceptable Stresses throughoutAcceptable Stresses throughout
Pile Driving Pile Driving and and
Equipment Equipment Data FormData Form
C o n t r a c t N o . : S t ru c t u r e N a m e a n d / o r N o .: P ro je c t :
P il e D r iv in g C o n t r a c t o r o r S u b c o n tr a c t o r: C o u n t y :
( P i le s d r iv e n b y )
M a n u f a c t u r e r : M o d e l N o . : H a m m e r T y p e : S e ri a l N o . : M a n u f a c t u r e r s M a x im u m R a te d E n e rg y : ( f t - l b s )
Hammer S t ro k e a t M a x im u m R a te d E n e rg y : ( f t )R a n g e in O p e ra t in g E n e rg y : t o ( f t - l b s )R a n g e in O p e ra t in g S t ro k e : t o ( f t )R a m W e i g h t : ( k ip s )M o d if ic a t io n s :
Striker W e i g h t : (k i p s ) D i a m e t e r: ( i n )Plate T h i c k n e s s : ( in )
M a t e ri a l # 1 M a te ri a l # 2( fo r C o m p o s i t e C u s h i o n )
N a m e : N a m e : Hammer A r e a : ( i n 2) A re a : ( in 2)Cushion T h i c k n e s s / P l a t e : ( i n ) T h ic k n e s s /P la t e : ( i n )
N o . o f P la t e s : N o . o f P l a t e s : T o t a l T h i c k n e s s o f H a m m e r C u s h io n :
Helmet(Drive Head) W e i g h t : (k i p s )
Pile M a t e ri a l: Cushion A r e a : ( i n 2) T h ic k n e s s /S h e e t : ( i n )
N o . o f S h e e t s : T o t a l T h i c k n e s s o f P ile C u s h io n : ( in )
P il e T y p e : W a l l T h ic k n e s s : ( in ) T a p e r : C ro s s S e c t io n a l A r e a : ( in 2) W e ig h t / F t :
PileO r d e re d L e n g t h : ( f t )D e s i g n L o a d : ( k ip s )U lt im a t e P il e C a p a c it y : ( k ip s )
D e s c r ip t io n o f S p li c e :
D r iv in g S h o e / C lo s u re P la t e D e s c ri p t io n :
S u b m it t e d B y : D a t e : T e l e p h o n e N o . : F a x N o . : T e l e p h o n e N o . : F a x N o . :
C o n t r a c t N o . : S t ru c t u r e N a m e a n d / o r N o .: P ro je c t :
P il e D r iv in g C o n t r a c t o r o r S u b c o n tr a c t o r: C o u n t y :
( P i le s d r iv e n b y )
M a n u f a c t u r e r : M o d e l N o . : H a m m e r T y p e : S e ri a l N o . : M a n u f a c t u r e r s M a x im u m R a te d E n e rg y : ( f t - l b s )
Hammer S t ro k e a t M a x im u m R a te d E n e rg y : ( f t )R a n g e in O p e ra t in g E n e rg y : t o ( f t - l b s )R a n g e in O p e ra t in g S t ro k e : t o ( f t )R a m W e i g h t : ( k ip s )M o d if ic a t io n s :
Striker W e i g h t : (k i p s ) D i a m e t e r: ( i n )Plate T h i c k n e s s : ( in )
M a t e ri a l # 1 M a te ri a l # 2( fo r C o m p o s i t e C u s h i o n )
N a m e : N a m e : Hammer A r e a : ( i n 2) A re a : ( in 2)Cushion T h i c k n e s s / P l a t e : ( i n ) T h ic k n e s s /P la t e : ( i n )
N o . o f P la t e s : N o . o f P l a t e s : T o t a l T h i c k n e s s o f H a m m e r C u s h io n :
Helmet(Drive Head) W e i g h t : (k i p s )
Pile M a t e ri a l: Cushion A r e a : ( i n 2) T h ic k n e s s /S h e e t : ( i n )
N o . o f S h e e t s : T o t a l T h i c k n e s s o f P ile C u s h io n : ( in )
P il e T y p e : W a l l T h ic k n e s s : ( in ) T a p e r : C ro s s S e c t io n a l A r e a : ( in 2) W e ig h t / F t :
PileO r d e re d L e n g t h : ( f t )D e s i g n L o a d : ( k ip s )U lt im a t e P il e C a p a c it y : ( k ip s )
D e s c r ip t io n o f S p li c e :
D r iv in g S h o e / C lo s u re P la t e D e s c ri p t io n :
S u b m it t e d B y : D a t e : T e l e p h o n e N o . : F a x N o . : T e l e p h o n e N o . : F a x N o . :
Ram
Anvil
Required Input Data Required Input Data Required Input Data Required Input Data
• HammerHammer– ModelModel– Energy level (stroke)Energy level (stroke)
• Driving systemDriving system– Hammer cushion material (E, A), thickness Hammer cushion material (E, A), thickness – Helmet weight (of entire assembly)Helmet weight (of entire assembly)– Pile cushion material (E, A), thicknessPile cushion material (E, A), thickness
(for concrete piles only)(for concrete piles only)
• HammerHammer– ModelModel– Energy level (stroke)Energy level (stroke)
• Driving systemDriving system– Hammer cushion material (E, A), thickness Hammer cushion material (E, A), thickness – Helmet weight (of entire assembly)Helmet weight (of entire assembly)– Pile cushion material (E, A), thicknessPile cushion material (E, A), thickness
(for concrete piles only)(for concrete piles only)
Required Input Data Required Input Data Required Input Data Required Input Data
• Soil Soil (from(from Borings with elevations)Borings with elevations)
– Type of soilsType of soils
– N-values vs depth N-values vs depth or other strength parametersor other strength parameters
– Elevation of water tableElevation of water table
• Soil Soil (from(from Borings with elevations)Borings with elevations)
– Type of soilsType of soils
– N-values vs depth N-values vs depth or other strength parametersor other strength parameters
– Elevation of water tableElevation of water table
Data Entry Data Entry Data Entry Data Entry
•Resistance distributionResistance distribution•SimpleSimple•From soil input wizardFrom soil input wizard
•For driveabilityFor driveability•Soil properties vs depth:Soil properties vs depth:
•Shaft unit resistance – requires calculationShaft unit resistance – requires calculation•End bearing End bearing - requires - requires calculationcalculation•Quakes and dampingQuakes and damping•Set-up factorSet-up factor
•Analysis depthsAnalysis depths
•Resistance distributionResistance distribution•SimpleSimple•From soil input wizardFrom soil input wizard
•For driveabilityFor driveability•Soil properties vs depth:Soil properties vs depth:
•Shaft unit resistance – requires calculationShaft unit resistance – requires calculation•End bearing End bearing - requires - requires calculationcalculation•Quakes and dampingQuakes and damping•Set-up factorSet-up factor
•Analysis depthsAnalysis depths
Available Help - Indirect Available Help - Indirect Available Help - Indirect Available Help - Indirect
GRLWEAP Help – DirectGRLWEAP Help – Direct: F3 : F3 GRLWEAP Help – DirectGRLWEAP Help – Direct: F3 : F3 Area calculator from any area input fieldArea calculator from any area input field..Area calculator from any area input fieldArea calculator from any area input field..
Final Recommendation Final Recommendation Final Recommendation Final Recommendation
• Perform sensitivity studies on parametersPerform sensitivity studies on parameters• Plot upper and lower bound Plot upper and lower bound results• Note: low hammer efficiency not always conservativeNote: low hammer efficiency not always conservative
• Read the helps and disclaimersRead the helps and disclaimers•On screen or after printing themOn screen or after printing them
• Compare results with dynamic testing Compare results with dynamic testing
• Perform sensitivity studies on parametersPerform sensitivity studies on parameters• Plot upper and lower bound Plot upper and lower bound results• Note: low hammer efficiency not always conservativeNote: low hammer efficiency not always conservative
• Read the helps and disclaimersRead the helps and disclaimers•On screen or after printing themOn screen or after printing them
• Compare results with dynamic testing Compare results with dynamic testing
SummarySummarySummarySummary• There are 3 distinctly different hammer modelsThere are 3 distinctly different hammer models
– External Combustion Hammer modelsExternal Combustion Hammer models– Diesel hammer and pressure modelsDiesel hammer and pressure models– Vibratory hammer modelVibratory hammer model
• There are 3 components in driving system modelThere are 3 components in driving system model– Hammer CushionHammer Cushion– Helmet and InsertsHelmet and Inserts– Pile Cushion (concrete piles only)Pile Cushion (concrete piles only)
• Model Parameters can be found in Model Parameters can be found in GRLWEAP Help Section or Hammer data file.GRLWEAP Help Section or Hammer data file.
• There are 3 distinctly different hammer modelsThere are 3 distinctly different hammer models– External Combustion Hammer modelsExternal Combustion Hammer models– Diesel hammer and pressure modelsDiesel hammer and pressure models– Vibratory hammer modelVibratory hammer model
• There are 3 components in driving system modelThere are 3 components in driving system model– Hammer CushionHammer Cushion– Helmet and InsertsHelmet and Inserts– Pile Cushion (concrete piles only)Pile Cushion (concrete piles only)
• Model Parameters can be found in Model Parameters can be found in GRLWEAP Help Section or Hammer data file.GRLWEAP Help Section or Hammer data file.
SUMMARY continuedSUMMARY continuedSUMMARY continuedSUMMARY continued
• The wave equation analysis works with “Static The wave equation analysis works with “Static Resistance to Driving” (SRD) plus a Damping or Resistance to Driving” (SRD) plus a Damping or Dynamic Resistance Dynamic Resistance
• Important analysis options include:Important analysis options include:
– Bearing GraphBearing Graph
– Inspector’s ChartInspector’s Chart
– Driveability Graph Driveability Graph
• The whole package is geared towards standard The whole package is geared towards standard analyses; some research options existanalyses; some research options exist
• The wave equation analysis works with “Static The wave equation analysis works with “Static Resistance to Driving” (SRD) plus a Damping or Resistance to Driving” (SRD) plus a Damping or Dynamic Resistance Dynamic Resistance
• Important analysis options include:Important analysis options include:
– Bearing GraphBearing Graph
– Inspector’s ChartInspector’s Chart
– Driveability Graph Driveability Graph
• The whole package is geared towards standard The whole package is geared towards standard analyses; some research options existanalyses; some research options exist
Summary: W.E. APPLICATIONSSummary: W.E. APPLICATIONSSummary: W.E. APPLICATIONSSummary: W.E. APPLICATIONS
• Design stageDesign stage– Preliminary hammer selectionPreliminary hammer selection– Selection of pile section for driveabilitySelection of pile section for driveability– Selection of material strength for drivingSelection of material strength for driving
• Construction stageConstruction stage– Hammer system approvalHammer system approval– Contractors use to select equipmentContractors use to select equipment– One means of estimating blow countOne means of estimating blow count– Inspector’s chart for variable hammer strokeInspector’s chart for variable hammer stroke
• Design stageDesign stage– Preliminary hammer selectionPreliminary hammer selection– Selection of pile section for driveabilitySelection of pile section for driveability– Selection of material strength for drivingSelection of material strength for driving
• Construction stageConstruction stage– Hammer system approvalHammer system approval– Contractors use to select equipmentContractors use to select equipment– One means of estimating blow countOne means of estimating blow count– Inspector’s chart for variable hammer strokeInspector’s chart for variable hammer stroke
Summary: Purpose of analysisSummary: Purpose of analysisSummary: Purpose of analysisSummary: Purpose of analysis
Develop driving criterionDevelop driving criterion
Final Set (Blow count) for a required capacityFinal Set (Blow count) for a required capacity
Final Set as a function of energy/strokeFinal Set as a function of energy/stroke
Check driveabilityCheck driveability
Final Set (Blow Count) vs. depthFinal Set (Blow Count) vs. depth
Stresses vs. depthStresses vs. depth
Optimal equipmentOptimal equipment
To Minimize Driving TimeTo Minimize Driving Time
Develop driving criterionDevelop driving criterion
Final Set (Blow count) for a required capacityFinal Set (Blow count) for a required capacity
Final Set as a function of energy/strokeFinal Set as a function of energy/stroke
Check driveabilityCheck driveability
Final Set (Blow Count) vs. depthFinal Set (Blow Count) vs. depth
Stresses vs. depthStresses vs. depth
Optimal equipmentOptimal equipment
To Minimize Driving TimeTo Minimize Driving Time
Recommended