secant pile construction

1

Secant Pile ConstructionOSIS Augmentation & Relief Sewer (OARS) Phase 2 Shafts # 3, 4 & 5

DFI ADSC Drilled Shaft SeminarSupport with Confidence

July 11-12, 2013

SecantPilesConstruction

Structuralfoundationelementconsistingofoverlappingpilesformingacontinuouswall.

Reinforcedconcrete(rebarcagesorsoldierpiles). Depthdependsuponfinaldesign&soilandequipment

characteristics. Pilesdiametersusuallybasedonmetrictoolingsize.Typically

760,880,1000and1180mmareused.Othersizesareavailable.

Secantpileswallstobecantileveredorbraced.Anygeometricshapeispossible.Themoreuniquetheshapethemoredifficultthebracingsystembecomes.

2

SecantPilesConstruction

Selectionofsecantpilesvs.otherearthretentionsupportsystemsisbasedon: Availableworkspace/sitelogistics Layoutofwall Impactrestrictionsonadjacentstructures Designparameters(stiffnessofwall,cutoffrequirements)

Materialhandlingrequirements Excavationcapabilitiesindifficultsoilconditions

SecantPilesConstruction

Sequenceofconstruction Guidewallsinstallation Primaryorlaggingpilesinstallation

Sectionalcasingrotationinadvanceofaugerremovingsoilinsideofthecasing

Dryorwetdrillingdependinguponsoilsconditions

Atdrillingcompletion,cleaningofpilebottom&placementofconcrete Freefallplacementindryconditionandwithatremie pipeinwetconditions

Extractionofcasingatpourcompletion Secondaryorclosingpilesinstallation

Sectionalcasingrotationinadvanceofaugerremovingsoilinsideofthecasing

Dryorwetdrillingdependinguponsoilsconditions

Atdrillingcompletion,cleaningofpilebottom&placementofreinforcementfollowedbyconcrete

Freefallplacementindryconditionandwithatremie pipeinwetconditions

Extractionofcasingatpourcompletion

3

SecantPilesConstruction

Sequenceofconstruction Guidewallsinstallation

SecantPilesConstruction

Sequenceofconstruction Primaryorlaggingpilesinstallation

Pilestypicallyunreinforced Lowerstrengthconcretecanbeused.Dependentondesignandfinal

4

SecantPilesConstruction

Sequenceofconstruction Primaryorlaggingpilesinstallation

Sectionalcasingrotatedaheadofaugercleaninginsideofcasing

SecantPilesConstruction Sequenceofconstruction

Primaryorlaggingpilesinstallation Sectionalcasingrotationaheadofaugercleaninginsideofcasing

5

SecantPilesConstruction Sequenceofconstruction

Secondaryorclosingpilesinstallation Pilesarereinforcedusingrebarcagesorsoldierpiles Highstrengthconcreteistypicallyused

Secondary Piles

Primaryiles

SecantPilesConstruction Sequenceofconstruction

Secondaryorclosingpilesinstallation Designmayrequiredallpilestobereinforced,inthatcasethelaggingpileswillbe

pouredusingstructuralconcrete

6

SecantPilesConstruction

Sequenceofconstruction Secondaryorclosingpilesinstallation

Pilesoverlapiscriticaltoguaranteecontinuityofwall Overlapisdependingofdepthofdrilledpilesanddrillingverticalitytolerance

SecantPilesConstruction Sequenceofconstruction

Secondaryorclosingpilesinstallation Loadbearingcaissonscanbeeasilyincorporatedintosecantwall

7

SecantPilesConstruction

CaseHistory

Project: OSISAugmentation&ReliefSewer(OARS)Phase2Shafts#3,4&5

ProjectInformation: 397Each 1180mmShafts

3independentsiteslocatedapproximatelymilefromeachother

Eachsecantpilewallsystemcomprisedofandropshaftandapproachchannel.

Eachsecantpilefortheaccessshaftwaskeyed5intoshalebedrock.

AverageSecantPileDrillLengthwas62.

OARSPhase2CaseHistory ShaftLocations

8

OARSPhase2Project SubsurfaceProfile

DropShafts: SecantPileCompressionRingDesign

All4,500psiConcrete

Noreinforcementrequiredfordesignaslongverticalitytolerancemet,

9

OARSPhase2Project Shaft3Layout

85 each Secant Piles @ 53 Long

OARSPhase2Project Shaft4Layout

173 each Secant Piles @ 64 Long

10

OARSPhase2Project Shaft5Layout

139 each Secant Piles @ 65 Long

OARSPhase2Project KODENUltrasonicDeviceVerticalityControl

11

OARSPhase2Project JeanLutzGyroscopeVerticalityControl

OARSPhase2Project KODENUltrasonicDeviceOutput

Pile #17B:Pile Depth = 57.83ftDeviation in x' direction = .78inDeviation in y direction = 1.57inTotal deviation = 1.75 < 7.08in = accepted

12

OARSPhase2ProjectPhotos

OARSPhase2ProjectPhotos

13

OARSPhase2ProjectPhotos

OARSPhase2ProjectPhoto

14

OARSPhase2ProjectPhoto

OARSPhase2ProjectPhoto

15

OARSPhase2ProjectPhoto

QUESTIONS?

SecantPilesConstruction