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 VIBRATORY HAMMER MODELHAMMER MODEL

VIBRATORY VIBRATORY HAMMER MODELHAMMER MODEL

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

GRLWEAP Hammer data fileGRLWEAP Hammer data fileGRLWEAP Hammer data fileGRLWEAP Hammer data file

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

DriveabilityDriveabilityDriveabilityDriveability

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