Sprew Part 1 of 3

Specificationfor pilingandembeddedretainingwalls• Specification• Contractdocumentationandmeasurement

• Guidancenotes

The Institution of Civil Engineersin collaboration with theHighways Agency, Ove Arup &Partners, and the Federation ofPiling Specialists

47~.’— .A~

ThE INSTITUTION OI~ Ci’ii. ENGINEERS

H UGH WAYSAGENCY

ARUP~

——

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.$ 0.

C’ThomasTelford

Publishedby ThomasTelfordPublishing,ThomasTelford ServicesLtd. 1 HeronQuay,LondonE144JD

First published1996Reprinted1997

Distributorsfor ThomasTelfordbooksareUSA: AmericanSociety of Civil Engineers,PublicationsSalesDepartment,345East47th Street,NewYork, NY 10017—2398Japan:MaruzenCo.Ltd, BookDepartment,3—10 Nihonbashi2-chome,Chuo-ku,Tokyo 103Australia: DA BooksandJournals,648WhitehorseRoad,Mitcham3132,Victoria

A cataloguerecordfor this book is availablefrom the British Library

ClassificationA ailabilitv: 1&n restrictedContent:RecommendationsbasedOfl currentpracticeStatus: RefereedUse?-: Practisingcivil andstructuralengineersanddesigners

ISBN: 0 72772566 1

© TheInstitution of Civil EngineersandCrown, 1996

All rights,including translationreserved.Exceptfor fair copying, no partof thispublicationmaybereproduced,storedin a retrievals~stemortransmittedin anyform or by any means,electronic, mechanical,photocopyingor other-wise.without thepriorwritten permissionof theBooksPublisher,PublishingDivision.ThomasTelford ServicesLtd, I HeronQuay,London£14 4JD.

This book is publishe.don the understandingthat the authorsare solelyresponsiblefor thestatementsmadeandopinionsexprcssedin it and that itspublicationdoesnot necessarilyimply thatsuchstatementsand...~oropinionsareor reflecttheviewsor opinions of the ptihlishcrs.F~eixeffort hasheenmadetoeiisttre that thestatementsmadeandtheopinionsexpressediii this publicationprovide accurate no esponsibilitvof an~a safeand guide: ho\vever, liability or rkind can be acceptedin this respectby thepublishersor theauthors.SpeciFiersof piles or retaitiing walls are responsiblefor ensuring that the standardrequirementsof this specificationareappropriatefor particularprojectsandforamending the specification where necessaryfor their pr~itct5 particularcircumstaiICes.

Typesetby \VestKevLtd. Falmouth.Cornwall.

I

I The Institution of Civil EngineersSpecificationis basedon the HighwaysAgencySeries1600 SpecificationPiling andEmbeddedRetainineWallswhichis Crowncopyrightandhasbeenadaptedwith the permissionof theControllerof Her Majesty’sStationeryOffice ahdtheHighwaysAgency.

Prin ted and bound in GreatBritain by Galliard (Printers Ltd. GreatYarmouth.Norfolk.

Foreword

TheInstitution of Civil EngineersSpec2[/ication forpiling, publishedin 1988,providedanew standarddocumentationfor thedifferentpilingconstructiontechniques.It wasthewish of theWorkingPartywhich producedit thatit shouldbequotedasastandardspeciftCa-

tion in contract documentationin the sameway as the thenDepartmentof TransportSpeczficalionfor highwayworks.

ThisnewSpecificationincludesmanysignificantchangesandit isbelievedthat it cannowbe adoptedas the defaclonationalstandardfor deepfoundationworks in the UK. Its origins startedwith aworkingpartyin theICEwhosetaskwasto extendthe 1988specifica-tionto covertheincreasinglyimportantfield ofembeddedretainingwalls.In 1992,OveArup andPartnerswerecommissionedby thenowreriamedHighwaysAgencyto reviewcompletelytheAgency’sSpec~fi-

0 cationforpiling anddiaphragmwalling. Ove Arup andPartnersaskedtheICEfor permissiontousethedraftdevelopedby theworkingpat-tvon embeddedwalls and to usethe existing ICE Specification as•astartingpoint. In addition,theywereaskedby the HighwaysAgencyto ensurethat the specialistcontractors,throughtheir tradefedera-tion, theFederationofPilingSpecialists,wereconsultedthroughoutthe development.The result is anew HighwaysAgencydocumentwhichprovidesacomprehensivespecificationformostload-bearingandembeddedretainingwall techniques.

The GroundBoard of the ICE consideredthat the HighwaysAgencydocumentationcould be revisedto leaveintact the techni-calcontentof the specificationbut to removereferencesto specificAgency standardsanddocumentation,and therebyto createanational standardspecification.The Highways Agency withouthindranceagreedto the ICE usingtheir new documentationandthis generouscontribution is acknowledgedby the inclusion oftheir logo on the ICE documentation.The ICE Specificationpre-

K sented herein is the endproduct of this collaboration.This isconsideredto be asignificantstepforwardfor the UK constructionindustry as it will mean that all deepfoundationworks can beLtndertakento acommonset of rulesandexpectations,with spe-cialistcontractoi-sableto developtheir own worksproceduresto aitniversallyusablestandard.

The first part of this volumecomprisesthe Spec~ficationforpilingandembeddedretainingwalls.It is anticipatedthatspecifierswill referonly to this Specificationand that it does not needto be repro-ducedfor eachcontract.Thedocumentneedsto containonly thespecialamenclmentsto theSpecificationthat the specifierswish tomakeandtheParticularSpecificationdetailscalled ttp by eachofthe relevantchapters.The secondpatt of the volttme contatnsgttidanceon particularissues(substantiallybasedon the ContractDocumentationandMeasurement~‘olumeof the ICE Spec~ficationforpiling. 1988).andthe third partcontainsspecificusernotesforeachchapterbasedon theHighwaysAgencyNotesforguidance.Partstwo andthreewottld not form part of a contractualspecification.bttt the advicecontainedin tlwm would normally be reflectedii:

contractdocumentation.

It is the aim of the Institution of Civil Engineersthat this Speci-fication should becomethe national Speczficationfor piling andembeddedretainingwalls.It is acknowledgedthattherearemanywhowould have avaluablecontribution to makewho havenot beenconsultedin the evolution of this Specification.Anybody withcomments,correctionsor improvementswhich the~’would like tosuggestfor considerationfor inclusion in the nexteditionof thisSpecificationshouldwrite to the Chairmanof the GroundBoardat the Institution of Civil Engineers.To allow sufficient time for abody of experiencewith this Specificationto develop,aseminarwill beheldattheendof 1998to reviewitscontentandto nominateaworkingparty to re~isethe Specification.

The co-operationbetweendesignersandspecialistcontractorsand that of the Highways Agency in the developmentof thisdocumentationhasbeenexceptional,andis surelya modelof howconstructionshouldbeundertaken.As with anytaskof thisnature,theamountof time andeffort expendedin the voluntaryservicegiven by the working parties and those providing constructivecommenthas beenunstinting, and the contributions are most

gratefullyacknowledged.

0

R H WrightChairman, ICE Ground Board

Acknowledgements

1988Working Partyfor ICE Speczficationfor pilingS.Thorburn,OBE, FEng,FICE,FiStructE,FASCE,MConsE;W. G.K FlemingBSc, PhD, MICE; J. Bickerdike BSc, DIG, FICE; A.Fawcett BSc, PhD: D. J. Palmer, MA, FICE, MConsE; J. MayBSc(Eng);I. H. McFarlaneBSc(Eng);D. Waite, FlStructE,MICE;J.Woodhouse.

ICE Working Group for draft Spec~ficationfor embeddedretainingwallsF. R.D. Chartres, BSc,CGeol, MICE;J. D. Findlay (Chairman), BSc,MSc, MICE; E. T. flaws, MA, FICE, FIPENZ; D. E. Sherwood,BSc,FICE; V. M. Troughton, BSc, MICE.

0 Highways Agency Specificationfor piling and embeddedretainingwalls, 1994D.I. Bush, BSc, PhD, MICE; T. J. P. Chapman, BE, MSc, MIEI,MICE; K W. Cole, BSc, MSc, FICE; B. Simpson, BA, MA, PhD,FICE; V. M. Troughton, BSc, MICE, D. Twine, BSc, MSc, MICE.This specification benefited from earlier contributions by J.Mitchell and A. Turner.

FPSMirror Groupfor HighwaysAgencySpec~ficationA. Fawcett,BSc,PhD;J. Findlay, BSc, MSc,MICE; W. G. K fleming(Chairman), BSc, PhD, MICE; L. Stansfield, FICE, FlStructE.

ICE Specification,for piling and embeddedretaining walls,1996T. J. P. Chapman, BE, MSc, MIEI, MICE; J. Findlay, BSc, MSc.MICE; J. A. Lord, BA, MA, PhD, FICE, MConsE; M. Alexander.

I

I

Contents

Specification 1

1. General requirements for piling work 31.1. DefinitionsandStandards 3

1.1.1. Definitions 31.1.2. British Standardsandother Codesof

Practice 4

1.2. ParticularSpecification 41.3. Progressreport1.4. Pile layout, designandconstruction1.5. MaterialsL6. Safety a

0 1.6.1. Standards 51.6.2. Life-sa~ingappliances 5L6.3. Diving 5

1.7. Groundconditions 3

1.8. Tolerances1.8.1. Settingout 71.8.2. Position 71.8.3. Verticality 7

1.8.4. Rake1.8.5. Foi-ciblecorrectionsto piles 7

1.9. Piling method 71.10. Piling programme /

1.11. Records S112. Nuisanceanddamage 9

1.12.1. Noiseanddisturbance 91.12.2. Damageto adjacentstructures 91.12.3. Damageto piles 91.12.4. Temporal)’support 9

1.13. Supervisionandcontrol of the Works 9

2. Precastreinforced and prestressedconcretepilesand precastreinforced concretesegmentalpiles 102.1. General 102.2. ParticularSpecification 1 02.3. Orderingofpfles 102.4. Materialsandcomponents 10

2.4.1. Steelandiron components 1()2.4.2. Pilejoints H2.4.3. Pik toes 1]2.4.4. Pile headreinforcement 21

2.5. Tolerancesin pile dimensions 112.6. Reinforcement 1]

2.6.1. Pr&castreinforcedandprestressedconcretepiles 11

2.6.2. Precastreinforcedconcretesegxflenta~piles 11

122.7. Forinwork

2.8. Concrete 122.8.1. Placingandcompactingconcrete 122.8.2. Protectingandcuring concrete 12

2.9. Prestressing 122.9.1. General 122.9.2. Concretestrength 122.9.3. Records 122.9.4. Post-tensionedpiles 132.9.5. Groutingprocedure 132.9.6. Grout 132.9.7. TestingWorksgrout 132.9.8. Batchinggrout 132.9.9. Mixing grout 132.9.10. Transportinggrout 132.9.11. Placinggrout in coldweather 132.9.12. Records 14

2.10. Pile quality 142.11. Marking ofpiles 142.12. Handling,transportationandstorageof piles 142.13. Driving piles 14

2.13.1. Strengthof piles 14 C)2.13.2. Leadersandtrestles 142.13.3. Performanceof dri~ing equipment 142.13.4. Lengthof piles 152.13.5. Driving proceduresandredrive

checks 152.13.6. Set 152.13.7. Driving sequenceandrisen piles 152.13.8. Preboring 16

2.14. Repairandlengtheningof piles 162.14.1. Repairof damagedpile heads 162.14.2. Lengtheningof precastreinforced

andprestressedconcretepiles 162.14.3. Lengtheningof precastreinforced

concretesegmentalpiles 162.14.4. Driving repairedor lengthenedpiles 16

2.15. Cutting off pile heads 17

3. Bored cast-in-placepiles 18 (3.1. General 183.2. ParticularSpecification 183.3. Supportfluid 183.4. Settingout 183.5. Diameterof piles 183.6. Boring 18

3.6.1. Boring nearrecentlycastpiles IS3.6.2. Casings IS3.6.3. Stabilityof pile bore 193.6.4. Spillageanddisposalof supportfluid 193.6.5. Pumpingfrom pile bores 193.6.6. Continuity of construction 19

3.6.7. Enlargedpile bases 203.6.8. Cleanlinessof pile bases 203.6.9. Inspection 20

3.7. Reinforcement 203.8. Placingconcrete 21

3.8.1. General 213.8.2. Workability of concrete 21

I

3.8.3. Compaction 213.8.4. Placingconcretein dry borings 213.8.5. Placingconcreteunderwateror

supportfluid 213.9. Extractionof casing 22

3.9.1. Workability of concrete 223.9.2. Concretelevel 223.9.3. Pile headcastinglevel tolerances 233.9.4. Temporarybackfilling abovepile

castinglevel 243.19. Cutting off pile heads 24.3.11. Grout 243.12. Pressuregrouting 24

3.12.1. Groutingofpiles 243.12.2. Methodof grouting . 243.12.3. Grout tubes 253.12.4. Pile uplift 253.12.5. Grout testing 253.12.6. Records 25

4.. Bored piles constructedusing continuousflight0 augersand concreteor grout injection throughhollow augerstems 264.1. General 264.2. ParticularSpecification 264.3. Constructionof pile 264.4. Settingout 274.5. Diameterof piles 274.6. Boring 27

4.6.1. Boring nearrecentlycastpiles 274.6.2. Removalof augersfrom theground 274.6.3. Suitability of boring equipment 274.6.4. Sealingthe baseof the auger 27

4.7. Depthof piles 274.8. Placingof concreteor grout 27

4.8.1. Concretemix designandworkability 274.8.2. Groutmix designandworkability 284.8.3. Equipmentfor supplyof concreteor

grout to piles 284.8.4. Commencementof concreteor

grout supply to eachpile 284.8.5. Rateof supplyof concreteor grout 2S4.8.6. Completionof concretingor

groutingof piles 2S4.8.7. Castinglevel of pile head 28

4.9. Reinforcement 284.10. Monitoring systemfor pile construction __

4.11. Cutting off pile heads 30

5. Driven cast-in-placepiles 315.1. Gei-ieral 31

5.2. ParticularSpecification 3 15.3. Materials 31

5.3.1. Permanentcasings 315.3.2. Pile shoes 31

5.4. Diameterof piles 313.c. Teinporarecasings 1

~.b. Enlargedpile bases .)

I

~.i. Driving piles5.7.1. Piling nearrecentlycastpiles5.7.2. Performanceof drivingequipment5.7.3. Lengthof piles5.7.4. Driving procedureandredrive

checksai.~. Set5.7.6. Driving sequenceandrisenpiles~.i.i. Preboring5.7.8. Internaldrop hammer

5.8. Repairof damagedpile headsandextendingof pilesto the cut-offlevel

5.9. Lengtheningof permanentpile casingsduringconstruction

5.10. Inspectionandremedialwork5.11. Reinforcement5.12. Placingconcrete

5.12.1. General5.12.2. Workability of concrete5.12.3. Compaction

.5.12.4. Placingconcrete5.13. Extractionof casing

5.13.1. Workability of concrete5.13.2. Concretelevel5.13.3. Vibrating extractors5.13.4. Concretecastingtolei-ances

5.14. Temporarybackfilling abovepile castinglevel5.15. Cuttingoff pile heads

6. Steel6.1.6.2.6.3.6.4.

6.5.6.6.6.7.

bearing pilesGeneralParticularSpecificationOrderingof pilesMaterials6.4.1. Pile shoes6.4.2. Strengtheningof piles6.4.3. Manufacturingtolerances6.4.4. Straightnessof sections6.4.5. Fabricationof piles6.4.6. Matchingof pile lengths6.4.7. Welding6.4.8. InspectionandtestcertificatesW~elders qualificationsWelding proceduresManufacturingprocesses6.7.1. Welded tubepiles6.7.2. Weldedbox pilesandproprietary

sectionsNon—destructivetestingof welds6.7.3.

6.7.4. Standardsfor welds6.8. Site-weldedbutt splices

6.8.1. Supportandalignment6.8.2. Weld tests6.8.3. Standardsfoi site buttwelds6.S.4. Protectionduringwelding

6.9. Coatingpiles for protectionagainstcorrosion6.9.1. Durability of coatings6.9.2. Definition

I

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6.9.3. Specialistlabour 396.9.4. Protectionduringcoating 396.9.5. Surfacepreparation 396.9.6. Applicationandtypeof primer 406.9.7. Control of humidityduring coating 406.9.8. Partsto bewelded 406.9.9. Thickness,numberandcolourof

coats 406.9.10. Inspectionof coatings 40

6.10. Marking, handlingandstorageof piles 406.10.1. Marking of piles 406.10.2. Handlingandstorageof piles 41

6.11. Driving ofpiles 416.11.1. Leadersandtrestles 416.11.2. Performanceof driving equipment 416.11.3. Length of piles 416.11.4. Driving procedureandredrivechecks 416.11.5. Set 416.11.6. Driving sequenceandrisenpiles 426.11.7. Preboring 42

6.12. Preparationof pile heads 4307. Timber piles 44

7.1. General 447.2. ParticularSpecification 447.3. Materials 44

7.3.1. Speciesof timber 447.3.2. Gradeof timber 447.3.3. Sapwood 447.3.4. Tolerancein timberdimensions 447.3.5. Condition of timber 457.3.6. Preservatives 457.3.7. Pile shoes 45

7.4. Inspectionandstacking 457.5. Treatmentwith preservative 457.6. Pile shoes 467.7. Pile heads 467.8. Splicing 46( 7.9. Driving piles 46

7.9.1. Leadersandtrestles 467.9.2. Performanceof driving equipment 467.9.3. Length of piles 477.9.4. Driving procedureandredrivechecks 477.9.5. Set 477.9.6. Splicedpiles 477.9.7. Driving sequenceandrisenpiles 477.9.8. Preboring 48

7.10. Preparationof pile heads 48

8. Reduction of friction on piles 498.1. General 498.2. ParticularSpecification 498.3. Pre-appliedbituminousor otherfriction-

reducingcostingmaterials 498.3.1. General 498.3.2. Protectionfrom damage 49S.3.3. Pile dri\ing 49

8.4. Pre-appliecllow-friction sleeving 49

8.5. Formed-in-placelow-friction surround 508.6. Pre-installedlow-friction sleeving 508.7. Inspection 50

9. Non-destructive methodsfor testing piles 519.1. Integritytestingof piles 51

9.1.1. Methodof testing 519.1.2. ParticularSpecification 519.1.3. Age of pilesat time of testing 519.1.4. Preparationof pile heads 519.1.5. SpecialistSub-contractor 519.1.6. Interpretationof tests 519.1.7. Report 529.1.8. Anomalousresults 52

9.2. Dynamicpile-testing 529.2.1. ParticularSpecification 529.2.2. Measuringinstruments 529.2.3. Hammer 529.2.4. Preparationof thepilehead 529.2.5. Interpretationof tests 52

.9.2.6. Time of testing 52 09.2.7. Measurementof set 539.2.8. Results 53

10. Static load testing of piles 5510.1. General 5510.2. ParticularSpecification 5510.3. Constructionof apile to betested 55

10.3.1. Notice of construction 5510.3.2. Methodof construction 5510.3.3. Boringor driving record 5510.3.4. Concretetestcubes 5510.3.5. Pi-eparationof working pile to be

tested 5610.3.6. Cut-off level 56

10.4. Supervision 5610.5. Safetyprecautions 56

10.5.1. General 5610.5.2. Kentledge 5610.5.3. Tensionpiles, reactionpilesand

groundanchorages 5610.5.4. Testingequipment 5710.5.5. Pile headfor compressiontest 5710.5.6. Pile connectionfor tensiontest 57

10.6. Reactionsystems 5710.6.1. Compressiontests 5710.6.2. Tensiontests 5710.6.3. Working piles 5810.6.4. Spacing 5810.6.5. Adequatereaction 5810.6.6. Careof piles 58

10.7. Equipmentfor applyingload 5810.8. Measurementof load 5810.9. Control of loading 5910.10. Measuringpile headmovement 59

10.10.1. Maintainedload test 5910.10.2. CRPandCRU test 5910.10.3. Optical levellingmethod 59

I

10.10.4. Referencebeamsanddisplacementgauges

10.11. Protectionof testingequipment10.11.1. Protectionfrom weather10.11.2. Preventionof disturbance

10.12. Notice of test10.13. Testprocedure

10.13.1. Proofloadtestprocedure(workingcompressionpiles)

10.13.2. Testprocedurefor preliminarycompressionpiles

10.13.3. Testingof pilesdesignedto carryloadin tension

10.14. Presentationof results10.14.1. Resultsto besubmitted10.14.2. Scheduleof recordeddata

10.15. Completionof a test10.15.1. Removalof testequipment10.15.2. Preliminarvtestpile cap10.15.3. Prooftestpile cap

0 11.General requirements for embeddedretainingwalls11.1. DefinitionsandStandards

11.1.1. Definitions11.1.2. BritishStandardsandotherCodes

of Practice11.2. ParticularSpecification11.3.. Progressreport11.4. Wall layout. designandconstruction11.5. Materials11.6. Safety

11.6.1. Standards11.6.2. Live-savingappliances11.6.3. Diving

11.7. Groundconditions11.8. Tolerances

11.8.1. Settingout

11.8.2. Positionandverticality11.9. Retainingwall constructionmethod11.10. Retainingwall programme11.11. Records11.12. Ntiisanceanddamage

11.12.1. Noise anddisturbance11.12.2. Damageto adjacentstructures11.12.3. Damageto completedwall elements

11.13. Supervision andcontrol of the Works

12. Diaphragm waUs12.1. General12.2. ParticularSpecification12.3. Guidewalls12.4. Materials

12.4.1. Concreteandsteelreinforcement12.4.2. Supportfluid

12.5. Dimensionsof panels12.6. Lxcavat]ori

12.6.1. Excavationnearrecentlycastpanel

596060606060

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GeneralWorkability of concreteCompactionPlacingconcrete

12.6.2. Stabilityof the excavation12.6.3. Cleanlinessof baseSteelreinforcementPlacingconcrete12.8.1.12.8.2.12.8.3.12.8.4.

12.9. Tolerances12.9.1. Guidewall12.9.2. Diaphragmwall12.9.3. Recesses12.9.4. SteelreinforcementTemporarystop-endsin diaphragmpanelsConcretelevelTemporarvbackfilling abovepanelcasting

12.10.12.11.12.12.

level12.13. Waterretention12.14. Instrumentation

13. Hard/hard secantpile walls13.1. General13.2. ParticularSpecification13.3. Guidewalls13.4. Materials

13.4.1.13.4.2.

13.5. Boring13.5.1. Boringnearrecentlycastpiles13.5.2. Stabilityof bore13.5.3. Cleanlinessof pile base13.5.4. Cleaningof supportfluid

13.6. Steelreinforcement13.7. Placingandcompactingconcrete

13.7.1. General13.7.2. Workability of concrete13.7.3. Compaction13.7.4. Placingconcretein dry boreholes13.7.5. Placingconcreteunderwateror

supportfluid13.7.6. Placingconcretein continuous

flight augerpiles13.7.7. Time periodfor excavationand

placingconcrete13.8. Tolerances

13.8.1.13.8.2.13.8.3.13.8.4.ConcretelevelBackfilling of emptyboreWaterretentionInstrumentation

13.9.13.10.13.11.13.12.

GuidewallSecantpilesRecessesSteelreinforcement

ConcreteandsteelreinforcementSupportfluid

14. Hard/soft secantpile walls14.1. General14.2. ParticularSpecification14.3. Guidewalls

12.7.12.8.

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Concreteandsteel reinforcementSelf-hardeningsltirry mixesSupportfluid

14.4. Materials14.4.1.14.4.2.14.4.3.

14.5. Boring14.5.1. Boring nearrecentlycastpiles14.5.2. Stabilityof bore14.5.3. Cleanlinessof pile base14.5.4. Cleaningof supportfluid

14.6. Steel reinforcement14.7. Placingandcompactingconcrete

14.7.1. General14.7.2. Workability of concrete14.7.3. Compaction14.7.4. Placingconcretein dry boreholes14.7.5. Placingconcreteunderwateror

supportfluid14.7.6. Placingconcretein continuous

flight augerpiles14.7.7. Time periodfor excavationand

placingconcrete14.8. Placingandcompactingself-hardeningslurry

mixes14.8.1.14.8.2.14.8.3.14.8.4.

14.9. Tolerances14.9.1.14.9.2.14.9.3.14.9.4.

14.10.14.11.14.12.14.13.

GeneralWorkability of self-hardeningmixPlacingself-hardeningmixesTime periodfor excavationandplacingself-hardeningmix

GuidewallSecantpilesRecessesSteelreinforcement

ConcretelevelBackfilling of emptyboreWaterretentionInstrumentation

80SoSoSI81SI81SiSISi8282528282

53

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15. Contiguous bored pile walls15.1. General15.2. ParticularSpecification15.3. Guidewalls15.4.Materials

15.4.1.15.4.2.

ConcreteandsteelreinforcementSupportfluid

15.5. Boring15.5.1.15.5.2.15.5.3.15.5.4.Steel reinfbrcement15.6.

15.7.

BoringnearrecentlycastpilesStability of boreCleanlinessof pile baseCleaningof supportfluid

Placingandcompactingconcrete15.7.1. General15.7.2. Workability of concrete15.7.3. Compaction

15.7.4. Placingconcretein drv bores15.7.5. Placingconcretetinderwateror

supportflt~id

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15.7.6. Placingconcretein continuousflight augerpiles

15.7.7. Timeperiodfor excavationandplacingconcrete

15.8. Tolerances15.8.1.15.8.2.15.8.3.15.8.4.

15.9. Concretelevel15.10. Backfilling of emptybore15.11. Instrumentation

GuidewallContiguouspilesRecessesSteel reinforcement

16. King Postwalls16.1. General16.2. ParticularSpecification16.3. Materials

16.3.1.16.3.2.16.3.3.

16.4. . Boring16.4.1. Boring nearrecentlycastpiles16.4.2. Stabilityof bore16.4.3. Cleanlinessof pile base16.4.4. Cleaningof supportfluidPlacementof King PostmembersSteelreinforcement

16.5.16.6.16.7.

16.8.16.9.16.10.16.11.

ConcreteandsteelreinforcementSupportfluidStructuralsteelwork

Placingandcompactingconcrete16.7.1. General16.7.2. Workability of concrete16.7.3. Compaction16.7.4. Placingconcretein dry bores16.7.5. Placingconcreteunderwateror

supportfluid16.7.6. Time periodfor excavationand

placingconcreteTolerancesConcretelevelBackfillingInstrumentation

17. Steelsheetpiles17.1. General17.2. ParticularSpecification17.3. Orderingof piles17.4. Materials

17.4.1. Standardsheetpiles17.4.2. Fabricatedsheetpiles17.4.3. Storage1 7.4.4. Clutch sealant

17.5. Pile handlinganddriving17.5.1. Pile handling1 7.5.2. Pile installationandextraction

17.6. Positionalandalignmenttolerance17.7. Welding

17.7,1.17.7.2.

Welders’qualificationsWeldingstandard

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17.8. Durability andprotection17.9. Piling records

9697

18. Integrity testing of wall elements18.1. Method of testing18.2. ParticularSpecification18.3. Ageof wall elementsat time of testing18.4. Preparationof headsor tops ofwall elements18.5. Specialistsub-contractor18.6. Interpretationof tests18.7. Report18.8. Anomalousresults

19. Instrumentation for piles andembeddedwalls19.1. ParticularSpecification19.2. Typeof instrumentation19.3.

19.4.19.5.19.6.19.7.

Extensometers19.3.1. General19.3.2. Rod extensometers19.3.3. MagneticextensometersInclinometersLoad cellsPressurecellsStraingauges19.7.1. General19.7.2. Straingaugesattachedto steel or

precastconcretepiles19.7.3. Straingaugesembeddedin concrete

19.8. Readings19.8.1.19.8.2.19.8.3.19.8.4.19.8.5.

GeneralCalibrationanddatacheckingTolerancesReportSpecialistinstrumentationcontractor

19.8.6. Monitoring equipment19.9. Protection19.10. Surveying

20. Generalrequirements for reinforced concrete20.1. General20.2. Cement

20.2.1.20.2.2.20.2.3.

20.3. Aggregate20.3.1.20.3.2.

20.4. Water20.4.1.20.4.2.

Typeof cementCementreplacementmaterialsStorageof cementandcementreplacementmaterials

Typeof aggregateStorageof aggregates

SuitabilityTests20.5. Admixtures

20.6. ConcretemiNes

20.6.1. Gradedesignation20.6.2. Mix20.6.3. Designedmix

989898989898989999

100100100101101101101101103103103103

103103104104104104104

105105105105

106106106106106

1061061061071107107107107107107107108

0

PrescribedmixIVfinimum cementcontent

GeneralPreliminarytrial mixesTrial mixesduring the workWorkability

20.6.4.20.6.5.

20.7. Trial mixes20.7.1.20.7.2.20.7.3.20.7.4.20.7.5. Variationsin mix

20.8. Testingworksconcrete20.8.1. Sampling20.8.2. Workability20.8.3. Works cubetests20.8.4. Standardof acceptance20.8.5. Recordsof tests

20.9. Batchingconcrete20.9.1. General20.9.2. Accuracyof weighingandmeasuring

equipment20.9.3. Tolerancein weights20.9.4. Moisturecontentof aggregates

20.10..Mixing concrete20.10.1. Typeof mixer20.10.2. Toleranceof mixerblades20.10.3. Cleaningof mixers20.10.4. Minimum temperature

20.11. Transportingconcrete20.11.1. Methodof transporting

20.12. Ready-mixedconcrete20.12.1. Conditionsof use20.12.2. Mixing plant

20.13. Steelreinforcement20.13.1. Condition20.13.2. Grade20.13.3. Bendingof reinforcement20.13.4. Placingof reinforcement20.13.5. Weldingof reinforcement

20.14. Grout20.14.1.20.14.2.20.14.3.20.14.4.20.14.5.20.14.6.

GeneralTestingworksgroutBatchinggroutMixing groutTransportinggroutPlacinggrout in coldweather

21. Support fluid21.1. Generalrequirements21.2. ParticularSpecification21.3. Evidenceof suitability of supportfluid21.4. Materials

21.41. Water21.4.2. Additivesto the waterMixing of supportfluidCompliancetestingof supportfluidSpillageanddisposalof supportfluid

21.5.21.6.21.7.

0

108108109109109109109109109109109109110110110110

110110110110110110110110111111111111111111111111111111111111111112112112112112

113113113113113113114114114115

C,

Contract documentationandmeasurement 117

Definitions 119

2. Appointment of contractors for piling andembeddedretaining walls 1202.1. Procedureprior to draftingtender

documents 1202.2. Methodof invitation of tenders 1202.3. Instructionsto tenderers 1212.4. Documentsformingpartof contract 1222.5. Model clausessuitablefor inclusionin

contractdocuments 1222.6. Information to be includedin tender

documents 1222.7. Information to be suppliedby the tenderer 1232.8. Evaluationof tenders 1232.9. Earlyfinal paymentto piling or walling

sub-contractor 124

0 3. Responsibilityfor piling andembeddedretaining walls 1253.1. Design 1253.2. Selectionof typeof pile or embedded

retainingwall 1253.3. Contractualarrangements 1263.4. Information to be providedby the Engineer 1263.5. Workmanship 1273.6. Non-Conformance 127

4. Useof theSpec~ficationforpiling and embeddedretainingwafl~ 1294.1. Application 1294.2. ParticularSpecificationclauses 1294.3. Concretein piles 1294.4. Tolerances 1304.5. Pile testingprocedures 1304.6. Degaussingsteelpiles 1314.7. Continuousflight augerpiles 131

5. Measurementof piling andembeddedretainingwall work 1325.1. General 1325.2. Preliminaries 1325.3. Obstructions 1335.4. Working levels 133s.c. Measurementof lengthsanddepths 1345.6. Cast-in-placeboredanddriven piles 1343.’. Specialrequirementsfor cast-in-placebored

piles 3355.8. Measurementof reinforcementin cast-in-place

piles I ~b5.9. Precastconcrete.timberandsteel piles I 3(~5.10. Jointedprecastconcretesegmentalpiles 1385.11. Preliminarypiles I 3=5.12. Testson working piles I ~=

I

5.13. Plantstandingduring tests 1385.14. Samplesandin-situ tests 1395.15. Removalof artificial andnaturalobstructions 1395.16. Paymenton dayworkbasis 1395.17. Observationsandrecords 1395.18. Outlinebills of quantities 139

AppendixA. Model bills of quantities 140Boredcast-in-placepiles 140Driven cast-in-placepiles 141Jointedprecastconcretesegmentalpiles 142Driven steelpiles 143Contiguousbored pile walls 143Secantboredpile walls 144Diaphragmwalls 145Steelsheetpiling 146

AppendixB. Model clausesfor incorporation asmaybe appropriate in main contracts orsub-contractsfor piling works 147

Appendix C. Scheduleof attendancesand facilitiesto beprovided by the client to a SteelPilingSpecialist 149

Appendix D. Guidanceon static load testingof piles 151

Appendix E. Guidance ondynamic load testingofpiles 154

Appendix F. Guidanceon integrity testingof piles 156

Appendix C. Drafting of a performancespecification 158

References 160

Guidance notes 161

Sectionson piling1. Generalrequirementsfor piling work 1632. Precastreinforcedandprestressedconcretepiles and

precastreinforcedconcretesegmentalpiles 1693. Boredcast-in-placepiles 1724. Boredpilesconstructedusingcontinuousflight augers

andconcreteor grout injection throughhollow augerstems 176

5. Driven cast-in-placepiles 1786. Steelbearingpiles 1797... Timber piles 1808. Reductionof friction on piles 1819. Non-destructivemethodsfor testingpiles 18210. Static load testingof piles 184

Sectionson embeddedretaining walls11. Generalrequirementsfor embeddedretaining walls 18612. Diaphragmwalls 191

13. Hard/hardsecantpile walls 19314. Hard/softsecantpile walls 19515. Contiguousboredpile walls 19616. King Postwalls 19717. Steelsheetpiles 19818. Integrity testingof wall elements 200

Sectionson piling and embeddedretaining walls19. Instrumentationfor pilesandembeddedwalls 20120. Generalrequirementsfor reinforcedconcrete 20221. Supportfluids 203

References 206

0

()

0I

I

uo!w3!Jpeds

3 0

r a- S

1. General requirements for piling work

1.1. Definitions and In this Specificationthe terms‘submitted’, ‘demonstrated’, noti-Standards fled’ and ‘reqUired’ mean‘submitted to the Engineer’, ‘demon-1.1.1. Definitions stratedto the Engineer’, ‘notified to the Engineer’and ‘required

by the Engineer’respectively.

Allowable pile capacity: a capacity which takesinto account thepile’s bearingcapacity, the materialsfrom which the pile ismade,the requiredloadfactor,settlement,pile spacing,down-drag, the overall bearingcapacityof the ground beneaththepiles and other relevant factors. The allowable pile capacityindicates the ability of the pile to meet the specified loadingrequirementsand is thereforerequiredto benot lessthan the

specifiedworkingload.Commencingsurface:is the level at which the piling equipment

first enterstheground.This neednot be the sameas the piling0 platform level.Compressionpile: a pile which is designedto resistanaxial force

suchas wouldcauseit to penetratefurther into theground.Constantrateof penetration(CRP) test: a testin which the pile is

madeto penetratethe soil ataconstantcontrolledspeed,whilethe force appliedat the top of the pile to maintainthe rateofpenetrationis continuouslymeasured.

Constant rateof uplift (CRU) test: a testin which thepile is madeto lift out of the soil ata constantcontrolledspeed,while theforce applied at the top of the pile to maintain the rate ofextractionis continuouslymeasured.

Cut-off level: is the level to which the pile concreteis trimmed inorderto connectthe pile to the structure.

DesignVerification Load (DVL): a loadwhich will besubstitutedfor the SpecifiedWorking Load for the purposeof a test andwhichmar be appliedto an isolatedor singlyloadedpile at thetime of testingin thegiven conditionsof the Site.The loadwillbe particularto eachPreliminaryor other testpile andshouldtake into accountthe maximumSpecifiedWorking Load for apile of the samedimensionsand materials,allowancesfor soilinducedforces such as downdrag(which may act in reverseunder temporal-v loading conditions), pile spacing and anyotherJ)articularconditionsof the testsuchasavariationof pileheadcastinglevel.

Kentledge:deadloadusedin a loading testLoad:a forceappliedto a pile undertest or in service.Load factor: theratio betweenthepilesultimatebearingcapaclt\

andmaximumsafebearingcapacity.The loadfactorrelatesonlyto the failure of tV’e pile—soil interface.Theallowablepile capa—city is determinedfrom the maximum safe bearingcapacitymakingall necessaryallowances.

Maintainedload test: a loading test in which eachinci-ement ofloadis heldconstanteitherfor a definedperiod of time or until

the rateof movement(settlementor uplift) falls to a specifiedvalue.

Pilesettlement:Theaxial movementat the top of thepile from tV

Specificationfor piling andembeddedretainingwalls. Thomas Te~ford, London, 1996. 3

positionbefore thecommencement/startof loading.For pilesloadedandunloadedthrough a numberof cycles, settlementshallbe the cumulativeverticalmovement.

Preliminary pile: a testpile installedbeforethecommencementofthe main piling worksor specificpartof theWorks.

Proof load: a load applied to a selectedworking pile to confirmthatit is suitablefor the loadatthesettlementspecified.A proofload shouldnot normallyexceedthe DesignVerification Loadplus 50% of the SpecifiedWorking Load.

Raking pile: apile installedat an inclination to thevertical.Reactionsystem: the arrangementof the kentledge,piles,anchor-

agesor spreadfoundationsthat provide a resistanceagainstwhich the pile is loadtested.

Resistance:theforcedevelopedby a pile in responseto a load.SpecifiedWorking Load (SWL): the specifiedloadon the headof

the pile as statedin the relevantParticularSpecification.Tensionpile: apile which is designedto resistan axial forcesuch

aswould causeit to beextractedfrom the ground.Testpile: anypile to which atest loadis, or is to be,applied.Ultimate bearing capacity: themaximum resistanceofferedby the

pile when the strengthof the soil is fully mobilized. If the 0ultimate bearingcapacityis to be derivedfrom a test in whichthe displacementis not largeenoughto mobilize thestrengthof the soil fully, the ultimate bearingcapacitymaybe derivedfrom an extrapolationof the testresults.

Working pile: one of the piles forming the foundation of astructure.

1.1.2. British Standards All materialsand workmanshipshall be in accordancewith theand other Codes of appropriateBritish Standards,Codesof Practiceandotherspeci-Practice fled standardscurrent at the date of tender exceptwhere the

requirementsoftheseStandardsor CodesofPracticearein conflictwith this Specification in which case the requirementsof thisSpecificationshall takeprecedence.

1.2. Particular The following mattersare, where appropriate,describedin theSpecification ParticularSpecification:

(a) supervisingofficer(b,) locationanddescriptionof the site(c~ natureof the works(d) workingarea(e,) sequenceof theworks(J) otherworksproceedingat thesametime(g) contractdrawings(12) office andotherfacilities for the Engineer(i,) submissionof information (in addition to Table 1.1)Q) responsibilityfor design(.4) performancecriteria for the structureto be supportedon

the piles(1) performancecriteria for pilesundertest (seeTable 1.3)(in) permissibledamagecriteria for existingciitical structures

or services0?) site datumandsite grid(0) restrictionson permissibleworking hours(‘p) detailsof groundinvestigationreports(q) additional ground investigation(r) conixnencingsurface(s) other particular requirements

I

4 Specification forpiling and embedded retaining walls. Thomas Telford. London, 1996.

1.3. ProgressReport

1.4. Pile layout,designandconstruction

TheContractorshallsubmitto theEngineeron thefirst dayof eachweekaprogressreportshowing thecurrentrate of progressandprogressduringthepreviousperiodon all importantitemsof eachsectionof theWorks.

Option 1 — Con tractor design

The Contractoris requiredto designandconstructpileshavingthe qualities of materialsandworkmanshipspecifiedandwhichupon testing meet the requirementsof the Specification forload—settlementbehaviour. The Contractor~sdesign shallcomprisethe calculationof individual pile lengthsbasedon theground conditionsrevealedby the site investigationto carry theSpecified Working Loads within the specified limits forload—settlementbehaviour.

The Contractorshallprovidewith his tenderascheduleof sizesandlengthsoftheworkingpilesincludingreinforcementandtheircorrespondingallowablecapacitiesto meet the requirementsofthe Specification.

Option2 — Engineerdesign

The Contractoris requiredto constructpiles of the type(s) anddimensionsspecifiedand having the qualitiesof materialsandworkmanshipspecified.Beforethecommencementof installationof theworkingpilestheContractorshallprovidetheEngineerwithascheduleof pile sizesandlengths.

1.5. Materials

1.6. Safety1.6.1. Standards

1.6.2. Life-savingappliances

1.6.3. Diving

1.7. Ground conditions

K

The sourcesof supplyof materialsshall not be changeduntil theContractorhas demonstratedthat the materials from the newsourcecan meetall the requirementsof the Specification.

Materials failing to comply with the Specificationshall be re-movedpromptlyfrom the site.

Safetyprecautionsshall complywith all currentlegislationinclud-ing the Health andSafety at Work Act 1974 or any subsequentre-enactmentthereofandwith BS 8004 and BS 8003.

The Contractorshall provide andmaintain on the Site sufficientproperandefficient life-savingappliances.The appliancesmustbeconspicuousandavailablefor useatall umes.

Site operativesshallbe conversantwith the useof safetyequip-mentanddrills shallbe carriedout sufficientlyfrequentlyto ensurethat all necessaryprocedni-escan becorrectlyobserved.

Diving operationsshall be carried out in accordancewith theDi~ing Operationsat Work Regulations(198]), Health andSafetyExecutive Publication 399, and any amendmentsor additionsthereto.

Before anydiving is undertakentheContractorshallsupply theEngineerwith two copiesof the codeof signalsto be employed.~nd shall haveacopy of the Codeprominentlydisplayedadjacentto the diving control station on the craft or structurefrom whichanydiving operationtakesplace.

No responsibilityis acceptedby theEngineeror Emploxerfor anyopinions or conclusionsgiven in any factual or interpretativegroundinvestigationreports.The Contractorshall reportimmedi-atelv to theEngineeranx circumstancewhich indicatesthat in theContractor~~opinion the ground conditionsdiffer from those

0

Specification forpiling and embedded retaining walls. Thomas Telford, London, 1996. 5

Table 1.1. Submissionofinformation. (Thefollowingsubmissionsshall be madeto theEngineerat thetimestated. Detailedrequirementsare listedunder the clausenumberindicatedin the relct’antposition.)

Section item AtTender

Prior tocommencingthe_War-ks

1.10

1.12.21.12.31.131.13

Duringthe Works

progress ReportPile layout, design and constructionPiling methodPiling programmeIRecordsMonitoring surveysIPiling sequenceSupervisorIOuallty Plan

IA.11.9

i.io

1.3

110

2 Material test recordsPile jointsMeans of maintaining concrete coverPrestressing recordsIGrouting recordsPile qualityHandling, loading of pilesPerformance of driving equipmentLength of pliesDriving procedureUplift and lateral displacement

24.2

2.122.13.3

2.3

2.9.32.9.122.10

2.13.42.13.52.13.7

3 Permanent casingStability of pile borecontinuity of construction .Means of maintaining concrete coverPressure grouting methodUplift reference framePressure grouting records

3.6.23.6.33663 73112.2

3.12.4 3.12.6

4 Monitoring grout propertiesIMonitoring system and records

4.8.24.10 4.10

5 Performance of drivihg equipmentILength of plIesDriving procedureUplift and lateral displacementMeans of maintaining concrete cover

5725.73

5.11

5.7.45.7.6

6 ordering of pliesInspection and test certificatesWelding proceduresManufacturing processesWeld testsProtection coatsIPerformance of driving equipmentLength of pilesDriving procedureUplift and lateral displacement

6.3

6.66.7

6.11.2

6.4.8

6.8.26.9.9

6.11.36.11.46.11.6

7 Origin of hardwoodInspectionTreatment with preservativePerformance of driving equipment .Length of pilesDriving procedureUplift and lateral dispiacement

7.3.17.47.5 7.57.9.2

7.9.37.9.47.9.7

8 Friction reduction method 8.1Pre-applied coatingPre-applied sleevingFormed-In-place low-friction surroundPre-installed sleevingRepairof damage

8.3.18.48.58.6

8.79 Specialist testing contractor

IIntegrity testing reportAnomalous resultscalibration certificatesDynamic Testing results

9.1.5I 9.1.7

9.1.89.2.29.2.8

10 Load application system• Notice of start of construction

Inclined piles for tension tests• Use of working piles as reaction

Adequate reactionMeasurement of loadNotice of testResultsRecoroed data

10.110.3.110.6.2

10.6.310.6.510.810.1210.14.110.14.2

6

0

Specification for piling and embedded retaining walls. Thomas Telford, London, 1996.

Table 1.1. Continued

Section Item AtTender

Prior to Duringcommencing the Works

the Works19 Instrumentation supplier etc.

Inclinometer-sCalibration and data checking

~Specialist Instrumentation contractor

19.219.419.8.2

19.8.419.8.5

•20 Types of cementCertificates of cement conformityWater testsConcrete workabllliltyEvidence of ASR complianceDetailed information on concrete mixTrial mixesWorkability of each batchConcrete cube tests

20.2.120.2.120.4.2

20.6.220.6.220.6.320.7.2

20.8.220.8.3

21 Support fluId mix 21.1Use and complIance 21.3

reportedin or which could havebeeninferredfrom thegroundinvestigationreportsor preliminarypile results.

1.8. Tolerances1.8.1. Setting out

1.8.2. Position

1.8.3. Verticality

1.8.4. Rake

1.8.5. Forciblecorrections to piles

1.9. Piling method

1.10. Pilingprogramme

Marker pinsfor the pile positionsshallbe setout andinstalledbythe Contractor.Immediatelyprior to installationof the piles, thepile positionsshallbe checkedby the Contractor.

Forapile with aspecifiedcut-offlevelator abovethecommencingsuifacethemaximumpermitteddeviationof thepile centrefromthe centre-pointshownin the setting-outshallbe 75 mm in anydirectionatcommencingsurfacelevel.An additionaltoleranceforapile with aspecifiedcut-off levelbelow commencingsurfacewillbe permittedin accordance~~ithClauses1.8.3and/or1.8.4.

The maximum permitteddeviationof the finished pile from theverticalat anylevel is 1 in 75.

Themaximumpermitteddeviationof anypart of thefinishedpilefrom the specifiedrakeis I in 25 for piles rakingup to 1 in 6 andI in 15 for pilesraking morethan I in 6.

Forciblecorrectionsto concretepiles to overcomeerrorsof posi-tion or alignmentshall not be made.If forcible correctionsaremade to steel piles the Contractorshall demonstratethat theintegrity, durability andpeiformanceof the piles havenot beenadverselyaffected.

TheContractorshall submitwith his tendei-all relevantdetailsofthe method of piling, the plant and monhoringequipmentheplansto adopt.Alternativepiling methodsmay be usedprovidedit is demonstratedthat theysatisfythe requirementsof theSpecifi-cation.

The Contractorshall submit a provisional programmefor theexecution of the Works at the time of tender and a detailedprogrammeprior to commencementoftheWorks.Heshall informthe Engineereachdayof the intendedprogrammeof piling forthe following dayandshall give 24 hours’ noticeof his intentionto work outside normal hours and at weekends.where this ispermitted.

‘U

I

Specification forpiling and embedded retaining walls. Thomas Telford, London, 1996, 7

i.ii. Records The Contractorshall keeprecordsas indicatedby an asteriskinTable 1.2 for the installation of eachpile andshall submit twosignedcopiesof theserecordsto theEngineernot later thannoonof the nextworking day after the pile was installed. The signedrecordswill form arecordof the work.

Any unexpecteddriving or boring conditionsshall benotedintherecords.

Table 1.2. Recordsto be kept (indicatedby an asterisk)

Notes

1. Pile types: A Driven precast concrete and steel pilesB Driven segmental concrete pilesC Driven cast-in-place concrete piles0 Bored cast-in-place concrete pilesE continuous flight auger concrete or grout piles

2. All levels shall be relative to the Datum specified in the Particular specification

3. All times shall be given in 24 hour format

Pile type

Data. A B C D E

contract * *

Pile reference number Ilocationi * *

* * *

Pile typeNominal cross-sectional dimensions or diameter * *

Nominal diameter of underream/baseLength of preformed pileStanding groundwater level from direct observation * *

or given site investigation dataDate and time of driving, redriving or boring from *

startto finish * *

Date of concreting * *

Ground level at pile position at commencement ofinstallation of pile (commencing surfacel * * * *

Working level on which piling base machine stands * *

Depth from ground level at pile position to pile toe * * * *

Toe level * * *

Pile head level as constructed * * *

Pile cut-off level *

Length of temporary casingLength of permanent casing 0

Type, weight, drop and mechanical condition ofhammer and equivalent information for other 0 *

equipmentNumber and type of packing used and type andconditions of dolly used during driving of the pile

set of pile or pile tube In millimetres per-lablows or number of blows per 25 mm of penetration

Temporary compression of ground and pileDriving resistance taken at 0.25 m Intervals *

Soil samples taken and in-situ tests carried out * * *

during pile formation or adjacent to pile positionLength and details ofand cover-to reinforcement * *

Concrete mix * *

Volume of concrete supplied to pile where thisis practical * *

All information regarding obstructions delays andother interruptions to the sequence of work

Pile forming equipment including rig no. *

Description of ground excavated *

Depth from commencing surface to changes in strataand to standing ground water and any fluctuations

Depth to average levels of concrete surface beforeand after withdrawing temporary lining

Type, torque, assessed efficiency of motorDepth to concrete surface after every concrete-loadFor raking piles, angle of rakeSupport fluid tests *

Monitoring information referred to in Section 4,8Level of top of reinforcement cage, as constructed

‘Ueup

I’

Pt’cm’

PfI

N

ml

Ni

K— I

UB Specification forpiling and embedded retaining walls. Thomas Telford, London, 1996.

1.12. Nuisanceanddamage1.12.1. Noise anddisturbance

1.12.2. Damage toadjacent structures

1.12.3. Damage to piles

1.12.4. Temporarysupport

1.13. Supervisionandcontrol of the Works

The Contractorshallcarryout the work in sucha mannerandatsuch timesas to minimizenoise,vibration andotherdisturbancein orderto complywith currenten~ironmentallegislation.

Particularrestrictionson permissibleworking hoursare statedin theParticularSpecification.

Permissibledamagecriteriafor adjacentstructuresor servicesaregiven in the ParticularSpecification.If in the opinion of theContractordamagemaybe causedto otherstructuresor servicesby his executionof the Works he shall immediately notifx- theEngineer.TheContractorshallsubmithisplansfor makingsurveysand monitoring movementsor vibration beforethe commence-mentof the Works.

The Contractorshall ensurethat duringthe courseof the work.displacementor damagewhich wouldimpair eitherperformanceor durabilitydoesnot occurto completedpiles.

The Contractorshall submit to the Engineerhis plannedse-quenceandtimingfor driving or boringpiles,havingregardto theavoidanceof damageto adjacentpiles.

TheContractorshallensurethatwhererequired,anypermanentlyfree-standingpiles are temporarilybracedor stayedimmediatelyafter driving to preventlooseningof thepiles in theground andto ensurethatno damageresultingfrom oscillation, vibration ormovementcan occur.

The Contractorshall keep upon the Works a competentsitesupervisorto be in chargeof pile constructionandinstallation.

The site supervisormust be experiencedin the type of pileconstructionnecessitatedby the Contract.A curriculum vitae ofthe supervisorshall be submittedprior to commencement.Thewhole time of the site supervisorshall be devotedto the pilingworks. The site supervisoi-shallnot be removedfrom the Workswithout theEngineerbeingnotified in advancewith atleastoneweek’snotice.

TheContractorshallsubmitoneweekprior to commencementof piling works his Qualit~- Plan for the Works. Subsequentrevi-sions,amendmentsor additionsshall be submittedprior to theirimplementation.Quality-AssuranceandQualityControldocumen-tation shallbemadeavailableon request.

Table1.3. Performancecriteriafor I)iles

Permittedsettlementat DVL.mm

Permittedsettlementat DVL+

1SWL,mm

lkNl

Maximum Maximumsettlement settlement

40

PileRef.Nos

Permittedtypeisi —

SpecifictionSection No.

Specifiedworkingload

Piledesig-nation

Loadfactor

DesignverificationLoad DVLlwhereapplicablel

Minimumpilelengthfromcut-offto toe

lkNl

K’

Minimumpilediameterordimensionsof cross-Section

Specification for piling and embedded retaining walls. Thomas Telford. London, 1996. 9

Precastreinforced and prestressedconcretepiles and precast reinforced concretesegmentalpiles

2.1. General

2.2. ParticularSpecification

All materialsandwork shallbein accordancewith Sections1, 2 and20 of this Specification,exceptwhere there may- be conflict ofrequirements,in which casethis Sectionshall take precedence.

The following mattersare, ~~-hereappropriate,describedin theParticularSpecification:

(a) specifiedworkingloads(b) additional performancecriteria for pilesunder test (also

seeTable 1.3)(c)(d)(e)(f}

(g)

(Iz)(i)(I)(k)(1)(in)

(12)

(o)

(p)(q)(r)

tvperof cementtypesandsizesof aggregategradesof concretedesignedor prescribedmixesandmaximumfreewatertocementratiomethodof testingconcreteworkabilitygradesandty’pes of andcoverto reinforcementtypesof prestressingtendongroutmarkingof pilespenetrationor depthor toe leveldriving resistanceor dynamicevaluationor settrial drives

p-elin~inarypilesuplift/latei-al displacementtiialspile shoes(whererequired)preboring or jetting or other means of easing piledriveability

(s~ detailedrequirementsfor driving records(including re-quirementsfor measurementof temporarycompressionsandredrives)

(1) disposalof cut-off headsof piles(u) otherparticttlai- requirements.

2.3. Orderingof piles

2.4. Materialsandcomponents2.41. Steel and ironcomponents

The Contractorshall ensurethat thepilesateavailablein timeforincorporationin theWorks.All pilesandproductionfacilities shallbe madeavailablefor inspectionat anytime. Pilesshall beexam-ined at the time of clelivei-v and any faulty units x-eplaced.Therecordsof testingof the concreteandsteel usedin the pilesshallbe submitted.

In the manufactureof precastconcretepilesandjointed pt-ecastconcretesegmentalpiles. fabricatedsteelcomponentsshallcomplywith BS 4360Grades43A or 50Aor BS ENIO 025 GradesFe 430Aot- Fe 510A, caststeel componentswith BS 3100,gtacleA (Al, A2or A3) andductileu-on componentswith BS 2789 Grades420/12.40(1,”] S or350~

2.

0

&

10 Specification forpiling and embedded retaining walls. Thomas Telford, London, 1996.

2.4.2. Pile joints

2.4.3. Pile toes

2.4.4. Pile headreinforcement

2.5. Tolerancesin piledimensions

2.6. Reinforcement2.6.1. Precastreinforced andprestressed concretepiles

2.6.2. Precastreinforced concretesegmental piles

Thejointsshallbe close-fittingfaceto faceandthelockingmethodshallbe suchas to hold thefacesin intimatecontact.Detailsof thedesign, manufactureand tests of the jointing systemshall besubmittedprior to the commencementof theContract.

Ajoin ted pile shallbecapableof withstandingthe samedrivingstressesasasingleunjointedpileof thesamecross-sectionaldimen-sionsandmaterials.

Thewelding of ajoint to mainreinforcementin lieu of a]appedconnectionwith projectingbarsaffixed to thejoint shall not bepermitted.

Eachpile joint shall be squareto the axis of the pile within atoleranceof 1 in 150. The centroidof the pilejoint shall lie within5 mm of thetrue axisof the pile element.

Pile toesshall be constructedso as to ensurethat damageis notcausedto thepile duringinstallation.

Pile headsshallbe so reinforcedor bandedas to preventburstingof the pile underdriving.

The cross-sectionaldimensionsof the pile shall be not less thanthosespecifiedand shall not exceedthem by more than6 mm.Eachfaceof apile shallnot deviateby morethan6 mm from anx-straightline 3 m longjoining two pointson thatface,nor shall thecentreofareaof thepile atanycross-sectionalongitslengthdeviateby more than 1/500 of the pile length from a line joining thecentresof areaat theendsof thepile. Wherea pile is lessthan3mlong the permitteddeviationfrom straightnessshallbe reducedbelow 6 mm on apro ratabasis in accordancewith actual length.

The headof apile elementor theendof the pile uponwhichthe hammeractsshallbesquareto the pile axiswithin atoleranceof 1 in 150.

Themainlongitudinalreinforcingbarsin pilesnotexceeding12min length shall be in onecontinuouslength. In piles more than12 m long,jointswill bepermittedin main longitudinalbarsso thatthenumberofjoints is minimized.Jointsin reinforcementshallbesuch that the full su-engthof the bar is effective acrossthejoint,following theguidanceof BS 8110.

Lap or splicejointsshallbe providedwith sufficient link barstoresist eccentricforces. Reinforcementshall be incorporatedforlifting andhandlingpurposes.

Spacersshall be designedand manufacturedusing dutablematerialswhich shallnot leadto corrosionof thereinforcementorspallingof the concretecover. Details of the meansby which theContractorplansto ensurethecorrectcoverto andpositionof thereinforcementshallbesubmitted.

If a pile is constructedwith a shapedpoint or shoe,thentheendof the pile shallbe symmetricalaboutthe longitudinal axisof thepile. Holesfor handlingor pitching,whereprovidedin thepile, shallbe lined with steel tubes:alternatively,insertsmay becastin.

Themain longitudinal reinforcingbarsshallbein onecontinuouslength. Sufficientreinforcementshallbe incorporatedfor liftingandhandlingpurposes.

Spacersshall be designedand manufacturedusing durablematerialswhichshallnot leadto corrosionof the reinforcementorspallingof the concretecover. Detailsof the meansby which the

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Specification for piling and embedded retaining walls. ThomaS Telford, London, 1996. 11

Contractorplansto ensurethecorrectcoverto andpositionof thereinforcementshallbe submitted.

2.7. Formwork

2.8. Concrete2.8.1. Placing andcompacting concrete

2.8.2. Protecting andcuring concrete

2.9. Prestressing2.9.1. General

2.9.2. Concrete

strength

2.9.3. Records

Formworkshallbe robust,cleanandso constructedas to preventloss of grout or aggregatefrom the wet concreteandensuretheproductionof uniform pile sections,free from defects.The pilesshallbe removedfrom the formworkin suchamannerthatsignifi-cantdamageto the pile is prevented.

Themethodof placingandcompactingthe concreteshallbesuchas to ensurethat the concretein its final position is denseandhomogeneous.

Immediatelyafter compaction,concreteshallbe adequatelypro-tectedfrom the harmful effectsof the weather,including wind,rain, rapid temperaturechangesandfreezing. Curing shall becarriedout in accordancewith BS 8110.

Pilesshallnot be removedfrom formwork until a sufficientpileconcretestrengthhasbeenachievedto allow thepile to behandledwithout significantdamage.

When acceleratedcuring is used the curing procedureshallensureno deleteriouseffects to the pile. Fourhoursmust elapsefrom thecompletionof placingconcretebefore the temperatureis raised.Therisein temperatureof theconcretewithin anyperiodof 30 minutesshall not exceed100Candthe maximumtempera-tureattainedshallnotexceed700C.Therateofsubsequentcoolingshallnot exceedthe rateof heating.

The Contractorshall ensurethat the Engineeris given adequatenoticeandeveryfacility for inspectingthe manufacturingprocess.

Prestressingoperationsshall be carried out only under thedirectionof an experiencedandcompetentsupervisor.All person-nel operatingthe stressingequipmentshall havebeentrained inits use.

The extensionsandtotal forces,includingallowancefor losses,shallbe calculatedbeforestressingcommences.

Stressingoftendonsandtransferofprestressshallbe carriedoutat agradualandsteadyrate. The force in the tendonsshall beobtainedfrom readingson arecentlycalibratedloadcell or pres-suregaugeincorporatedin the equipment.The extensionof thetendonsunderthe total forcesshall bewithin 5% of the calculatedextension.

The Contractor shall cast sufficient cubes,cured in the samemanneras the piles, to be ableto demonstrateby testingtwo cubesata time, with appropriateintervalsbetweenpairsof cubes,thatthe necessaryin Situ strengthof the concretehasbeenreached.

Concretein the piles shall not be stresseduntil two test cubesattain thenecessarystrength.

The Contractorshall keepdetailedrecordsof timesof tensioning.measuredextensions,pressuregaugereadingsor load cell readingsandtheamountof pull-in at eachanchorage.The Contractorshallalsocheckthecoverto reinforcementof eachpile andshallensureit isatleastthatspecified.Copiesof theserecordsshallbesubmittedwithin such reasonabletime from completionof eachtensioningoperationas ma\’ be required,andin anycasenot laterthannoonon the following working day.

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12 Specification for piling and embedded retaining walls. ThomasTelford, London, 1996.

2.9.4. Post-tensionedpiles

2.9.5. Groutingprocedure

2.9.6. Grout

0

2.9.7. Testing Worksgrout

2.9.8. Batching grout

2.9.9. Mixing grout

2.9.10.grout

Transporting

2.9.11. Placing grout incold weather

Apart from the requirementfor ductsandventsin post-tensionedpilesto begroutedafterthe transferof prestress,therequirementsfor pre-stressedpiles apply. Where specified in the ParticularSpecification,facilities shall be provided for retensioningpilesafterdriving.

Grout shall be mixed for a minimum of 2 minutesand until auniform consistencyis obtained.

Ductsshallnotbegroutedwhentheair temperaturein theshadeis lower than30C.

Beforegroutingis startedall ductsshallbe thoroughlycleanedby meansof compressedair which shallbe free of oils.

Groutshallbeinjectednearthe lowestpoint in theductin onecontinuousoperationandallowedto flow from theoutletuntil theconsistencyis equivalentto thatof thegroutbeinginjected.

Ventsin ductsshallbe providedin accordancewith Clause8.9.2ofBS 8110.

Groutfor prestressingshallhavethe following properties.

(a) The design and workability of grout to be used in theformationof pilesshallproducea mix which is suitableforpumping.

(b,) Grout shall consist only of Portlandcement,water andadmixtures.Admixturesareonly to be usedin accordancewith theManufacturefsinstructionsandshall compl~’withSection21.

(c,) Grout shall haveawater/cementratio as low as possibleconsistentwith the necessarvworkability, and the watercementratio shallnot exceed0.40.

(d,) Groutshall not bleedin excessof 2% after 3 hours,or amaximumof4%,whenmeasuredat 180Cin acoveredglasscylinderapproximately100 mm in diameterwith aheightof grout of approximately100 mm, andthewatershall bereabsorbedafter 24 hours.

Cubestrengthtestingshall be carriedout in accordancewith BSiSSi. A sampleshall consistof asetof six 100mmcubes.Threecubesshall be testedatseven daysandthe remainingthreeat 28daysafter casting.

The weighing andwater-dispensingmechanismsshall be main-tainedat all timesto within the limits of accuracydescribedin BS1305.

The weightsof eachcomponentof the mix shallbewithin 2%of the respectiveweightsper batch.

Cementgroutsshallbemechanicallymixedthoroughlyto pi-oducea homogeneousmix.

The groutshallbe mixed on site until a homogeneousgrout isobtainedandshallbekeptin continuousmovementuntil it is usedl.It shallbe usedwithin 30 minutesfrom thestartof mixing. Follow-ing mixing. the grout shall be passcdl through a 5 mm aperturesieveandi shallbe remixedif lumpsareretained.

Grout shall be transportedfrom the mixer to the l)osition of thepile in sucha mannerthat segregationd.f the mix doesnot occur.

Grout shall have a minimum temperatureof 50C when placed.

No frozen material or material con tainin~ ice shall be used for

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Specification forpiling and embedded retaining walls. Thomas Telford, London. 1996. 13

makinggrout.All plant andequipmentusedin the transportingandplacingof groutshallbe freeof ice that couldenterthegrout.

2.9.12. Records

2.10. Pile quality

2.11. Marking of piles

2.12. Handling,transportation andstorage of piles

2.13. Driving piles2.13.1. strength ofpiles

2.13.2. Leaders andtrestles

2.13.3. Performance ofdriving equipment

TheContractorshallkeeprecordsof grouting,including thedate,the pro.portionsof thegrout andany admixturesused,thepres-sure, detailsof interruptionand toppingup required.Copiesoftheserecordsshallbe submittedwithin suchreasonabletimeaftercompletionof eachgroutingoperationas maybe required,andinanx’ casenot laterthannoonon the following working day.

A certificateof qualityfrom thepile manufacturershallbeprovidedstating that the requirementsof this Specificationhavebeenful-filled during manufacture.

Eachpile shallbemarkedinsuchamannerthatit canbeidentified

~~~iththe recordsof manufacturewhich shall state the date of

casting, the cement~pe, concretegrade, elementlength, theprestressingforcewhereappropriateandanyotherrelevantdata.On deliverythe pilesshallbe accompaniedby recordsof manufac-ture.Lifting positionsshallbemarkedon eachpile in accordancewith the requirementsof design.

The methodandsequenceof lifting, handling, transportingandstoringpilesshallbe suchas to avoid shockloadingandto ensurethatthepilesarenotdamaged.Only designedlifting andsupportpointsshall be used.During transportandstorage,pilesshallbeappropriately’supportedunder themarkedlifting pointsor fullsupportedalongtheir length.

All pileswithin a stackshall be in groupsof the samelength.Packingof uniform thicknessshallbeprovidedbetweenpilesatthelifting points.

Concreteshallat no time be subjectedto loading,including itsown weight,whichwill inducea stress it exceedinocompressive in0.33 of its strengthat the time of loading or of the specifiedstrength,whicheveris the lesser.For this purposethe assessmentof thestrengthof the concreteandof thestressesproducedby theloadsshallbe submitted.

A pile shall be rejectedwhen the width of anytransversecrackexceeds0.3mm.The measurementshallbe madewith the pile inits workingattitude.

Pilesshallnotbedrivenuntil theconcretecubeshaveachievedthespecifiedcharacteristicstrengthand the pile has attained thestrengthto resistdriving stresses,whicheveris the greater.

At all stagesduringdriving anduntil incorporationinto thestruc-turethepile shallbeadequatelysupportedandrestrainedby meansof leaders,trestles,temporarysupportsor other guide arrange-mentsto maintainposition andalignmentandto preventsignifi-cantdamageto the pile

The efficiency and energyof the driving equipmentincludingwhenfollowers are usedshallbe notified. \Thererequiredin theParticularSpecification.dynamicevaluationandanalysisshallbeprovided.

Wherea drop hammeris used,themassof thehammershallbeat leasthalf thatof the pile. Forothertypesof hammertheenergydeliveredto the pile per blow shall be at leastequivalentto thatof

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14 Specification forpiling and embedded retaining walls. Thomas Telford, LondOn, 1996.

2.13.4. Length ofpiles

a drop hammer ofthestatedmass.Drophammersshallnotbeusedfrom floating craft in such a manneras to causeinstability of thecraftor significantdamageto the pile.

The length of pile to be driven in anyp9sition shall complywiththeContractor’sscheduleunlessotherwisespecifiedin theParticu-lar Specification.During the executionof the Woi~ks anx amend-mentsto thescheduledlengthsshallbe reportedto theEngineergiving adequatenoticeprior to installationof the pilesconcerned.

2.13.5. Drivingprocedures and redrivechecks

I0

2.13.6. Set

Thedrivingprocedureshallbesuchasto avoiddamageto thepiles.TheEngineershallbe given24 hours’noticeofcommencement

of the driving of the first pile.The Contractorshallgive adequatenoticeandprovideall nec-

essaryfacilities to enabletheEngineerto checkdriving resistances,setsandtemporarycompressions.

The driving of eachpile shallbecontinuousuntil the depthorset as required by the design hasbeenreached.In the eventofunavoidableinterruption to driving, the pile may be redrivenprovided it can subsequentlybe driven to the designeddepthand/orresistanceor setwithout damage.A follower shallnot beusedunlessthe setis revisedwhereapplicablein orderto takeintoaccountreductionin the effectivenessof thehammerblow.

Driving recordsshallbe madefor evervpile. This record shallcontaintheweightandfall of thehammeror ramandthenumberof blowsfor each0.25 in of penetration,unlessotherwisespecifiedin theParticularSpecification.

The Contractorshall inform the Engineerwithout delayif anunexpectedchangein driving characteristicsis noted.

The set and temporarycompressionshall be measuredand re-cordedforeachpile at thecompletionof driving unlessotherwisestatedin theParticularSpecification.

Whenaset is beingmeasured,the following requirementsshallbe met.

(a) The exposedpart of the pile shall be in good conditionwithout damageor distortion.

(b,,) The helmet,dolly andanypackingshall be in soundcon-di ti on.

(7,) Thehammerblowshallbein line with the pile axisandtheimpactsurfacesshallbe flat andat right anglesto the pileandhammeraxis.

(d) The hammershall be in good condition, delivering ade-quateenergyperblow, andoperatingcorrectly.

(7,) The temporarycompressionof thepile shall be recordedif required in theParticularSpecification.

Thesetshallberecordedeitheras thepenetrationin millimetre5per 10 blows or as the numberof blows required to produceapenetrationof 25 mm.

2.13.7. Drivingsequence and risenpiles

K~.

Piles shall be driven in a seqtienceto minimise an~’ detrimenuti

effects of heave and lateral displacementof the grotind. Thesequenceand method of piling including preboring shall limituplift andlateralmovementso that the final position of each pileis within the specified tolerances.At all times the deflectionsofeachpile from its axisasdriven shallnotbe suchas to causedamageor impair durability of the pilesor anystructuresor services.

The maximumpermitted uplift of eachpile cltie to am onepiledriven within a pile centreto centreradiusof eight pile diameters

Specification forpiling and embedded retaining walls. Thomas Telford, London, 1996. 15

is 3 mm unlessit can bedemonstratedby static load testingthatuplift exceedingthisamountdoesnot affect theability of the pileto meetthe requirementsof thisSpecification.

Evenif duringtheinstallationof preliminarypilesuplift is shownto be within the permitted maximum andthe preliminary pilestestedmeetthe requirementsof theSpecificationchecksof uplifton working pilesshallbe madeby the Contractoratleastonceaweek throughoutthe period of the piling work and the resultsreportedto theEngineer.

If preliminarypilesare not installed the Contractorshallcom-menceinstallationof workingpiles takingmeasuresto reduceoreliminateuplift until it can be establishedby site measurementsthatsuchmeasuresare no longernecessary.Thereafterchecksonuplift shallbe madeby theContractoratleastonceaweekandtheresultsreportedto the Engineer.

If a static loadtest showsthatapile which uplifted more thanthe maximumpermittedamountdueto anypile driven within aradiusof eightpile diametersdoesnot complywith the require-mentsof theSpecificationall suchpilesthatmax’ havebeenupliftedshallbe redriven.

If recordsandmeasurementsshowthatpileshavebeenlaterallydisplacedsoas to be outsidethepermittedtolerance,damagedorare of impaired durability the measuresthe Contractorplans toadoptto enablethe pilesto complywith the Specificationshallbeprovidedto the Engineer.

Laterallydisplacedpilesshallnot be correctedby forcible cor-rection.at the heads.

2.13.8. Prebo ring

2.14. Repair andlengthening of piles2.14.1. Repair ofdamaged pile heads

2.14.2. Lengthening ofprecast reinforced andprestressed concretepiles

2.14.3. Lengthening ofprecast reinforcedconcrete segmentalpiles

2.14.4. Drivingrepaired or lengthenedpiles

If preboringis specified,thediameteranddepthof preboreshallbe as stipulatedin theParticularSpecification.

Other meansto easepile drivability maybe usedprovidedthecompletedpilesmeetthe requirementsof the Specification.

If it isnecessaryto repairtheheadof apile beforeit hasbeendrivento its final level, theContractorshall carryout stich repairin awaywhich allows the pile-driving to be completedwithout furtherdamage.If the driving of a pile hasbeencompletedbut the levelof soundconcreteof the pile is belowthe requiredcut-offlevel, thepile shall be madegood to the cut-off level, or the pile cap orsubstructuremaybelocallydeepened,so thatthecompletedfoun-dation will safelywithstandthe specifiedworkingload.

Any provision for lengtheningpiles incorporatedat the time ofmanufactureshall be designedby the Contractor to resist allstressesto which it maybe subjected.

If no provision for lengtheningpileswas incorporatedat thetime of manufacttire,any methodfor lengtheningshall be suchthat the extendedpile including anyjoints is capableof takingsafely the sttessesduringdriving andunderload.

Wherepilesaredrivento depthsexceedingthoseexpected,leavinginsufficientprojectionfor penetrationinto thefollowingworks.thepilesshallbe extendedor replacedsothat thecompletedpilesarecapableof meetingthe requirementsof the Specification.

Repairedor lengthenedpilesshall not he driven until cubesfor theaddedconcretehavereachedthe specifiedcharacteristicstrengthof theconcreteof thepile.

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16 Specification forpiling and embedded retaining walls. Thomas Telford, LondOn, 1996.

2.15. Cutting off pileheads

When the driving of apile hassatisfiedthe Specification require-mentsthe concreteof the headof the pile shallbe cut off to thelevelspecified.Reinforcingbarsprojectingabovethislevelshallbeas specified.

Careshall be takento avoid shatteringor otherwisedamagingthe restof the pile. An~’ crackedor defectiveconcreteshallbe cutawayandthe pile repairedto providea full andsoundsection tocut-offlevel.

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Specification for piling and embedded retaining walls. Thomas Te!ford, London, 1996. 17

3. Bored cast-in-placepiles

3.1. General

3.2. ParticularSpecification

All materialsandworkshallbe in accordancewith Sections1, 3 and20 of this Specification,exceptwherethere may be conflict ofrequirements,in which casethis Sectionshall takeprecedence.

The following mattersare, whereappropriate,describedin theParticularSpecification:

(a) specifiedworkingloads(b~ additional performancecriteria for piles undertest (also

seeTable 1.3)(c) typesof cement(d) cementreplacementmaterials(e) trpesandsizesof aggregate

U) gradesof concrete(g~ designedor prescribedmixesandmaximumfree waterto

cementratio(h) methodof testingconcreteworkabilityU) gradesandtypesof andcover to reinforcementU) permanentcasing(k) supportfluid(1) pile dimensions(in) pressuregrouting(n) preliminarypiles(o,) trial bores(~) whetherpile inspectionby manneddescentis required(q) disposalof excavatedmaterial(i) otherparticularrequirements.

3.3. Support fluid

3.4. Setting out

3.5. Diameter of piles

3.6. Boring3.6.1. Boring nearrecently cast piles

3.6.2. Casings

Wheresupportfluid is usedto maintainthe stabilityof theexcava-tion it shall be in accordancewith Section21.

TheContractorshallcheckthecasingpositionforeachpile duringand immediatelyafter placing of the casing.Any checksby theEngineershallnot relievetheContractorof his responsibility.

The diameterof apile shallbe not lessthanthespecifieddiameter.Theaugerwidth shallbe checkedas necessaryandrecordedfor

eachpile to ensurethe specifieddiameteris achieved.A toleranceof 5%. on theaugerwidth is permissible.

Piles shall be bored in an order and in such a mannerthat nosignificantdamageis sustainedby previouslyformedpiles.

Temporarycasingsshall be of quality of material, length andthicknessadequatefor thepurposeof preventingwaterandunsta-ble soil from entering the pile excavations.A short length oftemporary casing shall be provided for all piles to provide anupstandof at leastI m abovesurroundinggroundlevel for safetyand to l)re\e1~tcontamination of the concretein thebore.

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18 Specification for piling and embedded retaining walls. Thomas Telford, London, 1996.

Temporarycasingsshall maintainthe excavationsto their fulldimensionsandensurethatpilesarecompletedto their full cross~sectionaldimensions.

The useof a vibrator to insertandwithdraw temporarycasingsis subjectto compliancewith Clause1.12 and to the methodnot

causingdisturbanceof thegroundwhichwouldadverselyaffecttheconstructionor the capacityof piles.

Temporarvcasingsshallbefreefrom significantdistortion.Theyshall be of uniform cross-sectionthroughout each continuouslength.During concretingtheyshallbe free from internalprojec-tions and encrustedconcretewhich might adverselyaffect theproperformationof piles.

Wherepilesareboredunderwaterorsupportfluid in an unlinedstate,the insertion of a full-length loosely fitting casing to thebottomof theboreprior to placingconcretewill notbepermitted.

Permanentcasingsshallbe as specifiedin the ParticularSpeci-fication.

Wheretheuseofa permanentcasingis specified,theContractorshall submit details of the type of casing and the method ofinstallationat the time of tender.

3.6.3. Stability ofpilebore

3.6.4. Spillage anddisposal ofsupportfluid

3.6.5. Pumping frompile bores

3.6.6. Continuity ofconstruction

Whereboring takesplace throughunstablewater-bearingstrata.the processof excavationand the support fluid and depth oftemporarycasingwhereemployed shall be such that soil fromoutsidethe areaof the pile is not drawn into the pile sectionandcavities are not createdoutsidethe temporarycasingas it is ad-vanced.

\Vhere a support fluid is usedfor maintaining the stability of abore, an adequatetemporarycasingshall be usedin conjunctionwith the supportfluid so as to ensurestabilitr of the strataneargroundlevel until concretehasbeenplaced.During constructionthe levelof drilling fluid in the pile excavationshallbe maintainedwithin the casedor stableboresothat it is not lessthan2 m abovethelevelofexternalstandinggroundwateratall times.unlessstatedotherwisein theParticularSpecification.

In theeventof a lossof supportfluid from a pile e>~cavation,theContractorshallnotify theEngineerof his intended actionbefore

contintling the work.

All reasonablestepsshallbe takento preventthespillageof supportfluid on the Site in areasoutsidethe immediate~icinitv of boring.Discardedfluid shall be removed from the Site without undtmedelay.Any disposalof fluid shallcomplywith the requirementsofcurrent legislationand all relevantauthorities.

Pumpingfrom pile boresshallnot be permitted unlessthe bome

hasbeensealedagainstfurther water entrv by casingor unlesstIjesoil is stableandwill allow pumpingto takeplacewithotit grounddlisturbancebelow or aroundthe pile.

The pile shall he boredand theconcreteshall be placed withoutstichdelayas wouldl leadto impairmentof the performanceof thc

pile.The time period during which each l)ild’ is excavatedand tIn-

concreteis l)l~Icedl shallnot exceed12 hours.The timeperiodshallstart when excavation b&low the temporary lining tubes com-mences(exceptfor casingsstmchasusedin secantpiling which lea~a significant annulusbetweenthe casingandthe soil). \~‘here the

sequenceis suchthat the time j)eriodl of 12 hourswi Ihe exceededleven if no delaysare taken into account, a realistic

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forpiling and embedded retaining walls. ThomasTelford, London, 1996.

timeperiodduringwhich thepile is excavatedandconcreteplacedshallbestatedin theContractor’smethodstatement.The Contrac-tor shall adviseon the likely effect of this extensionof the pileconstructionperiodon theperformanceandcapacityof the pile.

3.6.7. Enlarged pilebases

3.6.8. Cleanliness ofpile bases

3.6.9. Inspection

3.7. Reinforcement

A mechanicallyformedenlargedbaseshallbe no smallerthanthedimensionsspecifiedandshallbe concentricwith the pile shafttowithin atoleranceof 10% oftheshaftdiameter.Theslopingsurfaceof thefrustumformingtheenlargementshallmakean angleto theaxisof the pile of notmorethan350,

At the specifieddiameterof theunderreamat theperimeterofthe basethereshallbe a minimum height of 150 mm.

On completionof boring loose,disturbedor softenedsoi] shallberemovedfrom theboreusingappropriatemethods,whichshallbedesignedto clean while at the same time minimizing grounddisturbancebelowthe pile bases.Whereused,support fluid shallbemaintainedatsuchlevelsthroughoutandfollowing thecleaningoperationthat stability of theboreis preserved.At all timeswhenthe pile headis unattended,the boreshallbe clearlymarkedandfencedoff soas not to causeasafetyhazard.

Eachpile borewhich doesnot containstandingwateror supportfluid shallbe inspectedfrom thegroundsurfaceprior to concretebeingplacedin it to ensurethe baseis adequatelyclean andthatthe shaft is stableandwithin the specified tolerances.Adequate

meansof lighting, measuringtapesand a means of measuringverticalityshallbeused.Forpilesof 750mmdiameteror largerandwhere mannedinspection of the pile baseis specified in theParticularSpecification,equipmentshall be providedby the Con-tractor to enablehis representativesto descendinto the boreforthepurposeof inspection.The Contractorshallprovideall neces-sarv facilities to enabletheEngineerto makean inspectionof anypile excavationincluding facilities to checkthe depth,verticalityandposition.Thefull requirementsof BS 8008shallbe followed.

The Contractorshall designatea Supervisorto superviseeachinspection.The Supervisorshallhaveacopy of BS 8008andshallensurethatevervpersoninvolved in the descentof piles is familiarwith its requirements.

The numberofjoints in longitudinal steelbarsshallbekeptto aminimum.Jointsin steelreinforcementshallbe such that thefullstrengthof eachbaris effectiveacrossthejoint andshall be made

so that thereis no detrimentaldisplacementof the reinforcementduring the constructionof the pile, following the guidanceof BS8110.Reinforcementshall be maintainedin its correctpositionduring concretingof the pile. to allow a vertical toleranceof÷1507—50mm on the level of the reinforcementprojectingabovethefinal cut-off level. Wherereinforcementis madeup into cages.theyshallbe sufficiently rigid to enablethem to be handled,placedand concretedwithotit damage.If thecageis to beweldedtogether,weldingshall hecarriedotit to therequirementsof 135 7123.Detailsof the proceduresshotild be submittedprior to commencementofthe works.

Unless otherwise51)ecifiedl, reinforcement shall extendto thebaseof thepild~ or to at least3 in belowthebottom ofthe temporarycasin(T whicheveris the lesser.

Spacers shall be designed and manufactured using durablematerialswli ich shallnot lead tu corrosionof therein furcementor

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20 Specification forpiling and embedded retaining walls. Thomas Telford, Londo~

spallingof the concretecover.Detailsof the meansby which theContractorplansto ensurethecorrectcoverto andpositionof thereinforcementshallbe submittedprior to commencementof theworks.

3.8. Placing concrete3.8.1. General

3.8.2. Workability of

concrete

3.8.3. Compaction

3.8.4.in dry

Placing concreteborings

3.8.5. Placing concreteunder water or supportfluid

The workability and methodof placing of the concreteshall besuch thatacontinuousmonolithicconcreteor grout shaft of thefull cross-sectionis formed.Concreteshallbe transportedfrom themixer to thepositionof thepile in sucha mannerthatsegregationof the mix doesnot occur.

Theconcreteshallbeplacedwithoutsuchinterruptionaswouldallow thepre~iouslyplacedbatchto haveachievedastiffnesswhichpreventsproperamalgamationof the two concretebatches.

The Contractorshall take all precautionsin the designof themix andplacingof theconcreteto avoid archingof the concretein a temporarvcasing.No soil, liquid or otherforeignmattershallbepermittedto contaminatethe concrete.

Workability measuredat the time of dischai-geinto the pile boreshall bein accordancewith the limits shownin Table3.1.

Internalvibratorsshallnot be usedto compactconcrete.

Measuresshall be takento ensurethat the structuralstrengthoftheconcreteplacedin all piles is not impaired throughgroutloss.segregationor bleeding.

The method of placing shall be such as to ensurethat theconcreteor grout in its final position is denseandhomogeneous.Concreteshallbe introducedinto thepile via ahopperandsuitablelength of rigid delivery tube to ensurethat the concretefallsvertically and centrallydown the shaft. The tubeshallbeat least3 m long.

Before placing concrete,measuresshall be taken in accordancewith Clauses3.6.8and3.6.9to ensurethereis no accumulationofsilt or othermaterialatthe baseof the boring,andtheContractorshall ensurethatheavily contaminatedsupportfluid, which couldimpair the free flow of concretefrom the tremie pipe, has notaccumulatedin the bottomof the hole.

A sampleof supportfluid shallbetakenfrom thetopandbottomof the boring using an appropriatedevice. The fluid shall beprepared,sampledandtestedasstatedin theContractor’ssubmis-sion. If testsshowthe fluid doesnot complx with the limits statedby theContractorfor theparticulartypeof stipportfluid, the fltiiclshall be wholly or partly replacedas appropriatebeforeconcreteis placed.

Concreteto be placedtinder water or support fluid shall beplacedby tremie in one continuousoperationand shall not bedischargedfreely into the water or support fluid. Pumping ofconcretemaybe usedwhereappropriate.The bottom endl of thetremiemustbe squareto the axisof the tremieandits circumfej--

mustbe continuous.The tremie mtist be fully charged wi ticoncretebefore ii. is lifted off the baseof the pile.

The concreteshall be of high workability in accordancewit iTable3.1, NIix C andcementcontentin accordancewith Secti(~2() andTable 3.1,Mix C.

The concreteshallbeplacedin suchamannerthatwill not cau\rsegregati d)n d)f the mix.

The dlepthsto the surfaceof theconcreteshall be meastiredan j

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Specification forpiling and embedded retaining walls. Thomas Telford. London, 1996.

the lengthof the tremietubesrecordedatregularintervalscorres-ponding to the placing of each batch of concrete.The depthsmeasuredandvolumesplacedshall be plottedimmediatelyon agraph and comparedwith the theoretical relationshipof depthagainstvolume.

Thehopperandpipeof the tremieshallbe cleanandwatertightthroughout.The pipeshall extendto the baseof thebore andasliding plug orbarriershallbe placedin thepipeto preventdirectcontactbetweenthe first chargeof concretein thetremieandthewater or support fluid. The pipe shall at all times penetratetheconcretewhich haspreviouslybeenplacedwith a minimum em-bedmentof 3 m andshallnotbe withdrawnfrom the concreteuntilcompletionof concreting.A sufficientquantityof concreteshallbemaintainedwithin the pipe to ensurethat the pressurefrom itexceedsthatfi-om thewaterorsupportfluid. Theinternaldiameterof the pipe of the tremie shallbe of sufficient size to ensuretheeasyflow of concrete.It shallbesodesignedthatexternalprojec-tionsare minimized,allowing thetremie to passwithin reinforcinocageswithoutcausingdamage.The internalfaceof thepipeof thetremieshallbe free from projections.

3.9. Extraction ofcasing3.9.1. Workability ofconcrete

3.9.2. Concrete level

Temporary~casingsshall be extractedwhile the concretewithinthem remainssufficiently workableto ensurethat the concreteisnot lifted. During extraction the motion of the casingshall bemaintainedin an axial direction relativeto the pile.

Whenthecasingis beingextracted,asufficientquantityof concreteshallbemaintainedwithin it to ensurethatpressurefrom externalwater, supportfluid or soil is exceededandthat thepile is neitherreducedin sectionnor contaminated.

The concretelevel within a temporarycasingin adryboremaybe toppedup wherenecessaryduringthecourseof casingextrac-tion so that the baseof the casingis always below the concretesurfaceuntil the castingof the pile hasbeencompleted.

Adequateprecautionsshall be takenin all caseswhereexcess

Table3. 1. Pilingmix workability

Piling mixworkability

Workability Typical Conditions of use

IThe concrete and aggregate sizes must

Target slump

be compatible with the reinforcement spacingi

flow range,mm mm

A not 75—1 25 Placed into water-free unlined or permanentlyapplicable lined bore of 600mm diameter or over, or where

casting level lies below temporary casingreinforcement spaced at 100mm centres crgreater, leaving ample room for free movementof concrete between bars.

B Target Slump~ Where reinforcement is spaced at less tharflow 100—175 100 mm centres: where cut•off level of concrete500 +1—50 is within temporary casing; where pile bore is

water-free and the diameter is less than 600 mm.

c Target Slump Where concrete is to be placed by tremie underflow iso or water or support fluid or by pumping or by550 +1—SO more continuous flight auger.

.me slump test method is not suited to these very high workabilities and the flow test is to be preferreo.

op

22 Specification forpiling and embedded retaining walls. Thomas Telford, London, 1996.