Method statement in english.docx

Method statement in english.docx

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Methodstatementinenglish

MethodStatementforConstructionofEPCProject

@UnitedArabEmirates

1、General

TheRenovation&ExpansionofEPCHarbour@UnitedArabEmiratesincludescivilbuilding&marineworksanditsancillaries.Themainworksare:

removalofexistingbuildings&re-construction;expansionoftheexistingquaywall,suchascast-driveninsituquaywallpiles,boredanchorwallpiles,anchoragesysteminstallation,paving,basindredging,dismantantling&re-installationofmarinefurnitureetc.

2、Constructionarrangementforworkingprocedures

Regardinggeneralconstructionarrangement,totallythreeworkingfacetsi.e.civilbuilding,marineworks&installationofplant&equipmentshallbedevelopedalternatively&logically,ofwhich,thequaywallconstructionisthekeylineforthewholeworks.

Thesiteofficewouldbemadeofcaravans,whicharemobilefromtimetotimeinaccordancewiththesiteprogresswithoutcausinganyaffecttositework.

Thequaywallwillbeconstructedinsections.Onlywhenthe200m-longnorthernquaywallisbuilt&putintousesoastoguaranteethenormalrunningofharbouroperationcanwestarttheremainingquaywallwork.

Thecast-driveninsituquaywallpilesareproposedtostartfromthenorthernbankoftheexistingquaywall&proceedtothedirectionofthewesternbank.Afterinstallationofthetubularpilestothedesignedlevel,aconstructionplatformsupportedbytheland-basedtubularpiles&existingquaywallcouldbebuilt.Thedrillingplantcouldbepositionedontheplatform&beusedtodothepilefoundationwork.Theboredanchorwallpileswouldbeconstructedatthesametime.Thedismantlingoftheexistingquaywallpavement,piles&cappingbeamsetc&installationoftheanchoragesystemshouldalsobecarriedoutcloselyalongwiththepilefoundationworkwithoutcausingeffectonthetierodworks.

Thedredgingofthebasincouldbedividedintotwosteps:

i.ethefirststepistodredgethearea50moutsidefromthecopeline,theremainedareainfrontofthecopelinewouldbeexcavatedwiththemainquaywallbodyiscomplete.

Powersupply:

twosetsofgeneratorswouldbeprovidedforpowersupply.

Mainflowchartofworks：

ConstructionPreparation

Landbasedpilepositioning

Anchorbeam

Theboringforming&concreting

Dismantlingofpartofquaywall

BackfillingbeforeAnchorbeam

Workbehindquaywall

Workcompletion

Revetmentworks

Boredpileconcrete

Superstructureofquaywall

Tierodadjustment

Backfillingbehindthepile

Drivingofpiles

Platformconstruction

Underwaterchecking&removalofobstruction

Dredgingofbasin

Tierodworks

3、MainWorkingProcedures

3.1Cast-driveninsituQuayWallPiles

Drivingoftubularpiles

Priortopiledriving,thediversshallbeemployedtochecktheseabed,alltheobstructionsifanyshouldberemoved.Theexistingquaywallshouldbestrengthenedifdeemednecessarysoastoguaranteethesafe&smoothdrivingofpiles.Thetubularpilesshouldbeaccuratelypitchedbymeansofaguideframe.Theguideframewillbesupportedbytwotubularpiles&connectedwiththecappingbeamhorizontallysoastoeasilyadjustthepositioning.Thelengthoftheguideframeshouldbe10mandtotally8Nosofpilescouldbedrivingduringeachpanelplacement.Whenthefirstpaneliscomplete,theguideframewouldbemovedforwardforthepiledrivingofnextpanel.Thetubularpileswillbedrivenbymeansofa40tcrawlercraneequippedwithhydraulicvibratinghammeruntilthedesignedbottomlevelisobtained.Theheadlevelofthetopofthepilestobeslightlyhigherthantheexitingquaywallsurface.

Duringpiledriving,attentionshallbegiventomaintainatrulyverticalalignmentsoastoavoidanyproblemsduetopileoutofverticality&causingunnecessarydamagetothepileears.

Boringdrilling&castingofreinforcedconcrete

Afterthetubularpilesaredriven,aplatformwillbebuiltwiththesupportofthetubularpiles&theexistingquaywall.TheplatformwillbecoveredwithsteelplateuponwhichtheGPS-15drillingmachinewillbesupported.Theboring&concretingcastingwillbecarriedoutinanintermittentmanner,i.e.asapileisconcreted,thenexttwoadjacentpileswillbeleftforawhileandthefourthalongwillbeconcretedsoastokeepanintervaloftwo

（2）pilesspacetoguaranteetheworkquality.

（pleaseseethefollowingillustration）

①④⑦②⑤⑧③⑥

A）thesketchforformingtheboringisasfollows：

BWorkingflowchart

C/Constructionholdpoints

a）Survey&settingout

ThecentralpointsofeachpilecouldbesetoutbymeansofTotalStation&thesurveyrecordshouldbesubmittedforthedouble-checking&finalapprovaloftheConsultant.Eachpilewouldbepitchedsecurelybymeansofguideframe.

b）Positioningofdrill

Beforeassemblyofthedrill,allthepreparatoryworkshallbewelldone.Themovablerails&woodensleepersshallbeinstalledinsuchamannerthatthestabilityofthedrillisalwaysmaintained.Theslurrypumpshouldbeasclosetothepilepositionaspossible.Inthemeantime,theslurryrecyclingsystemshouldbewellpreparedtoassurethattheslurrycanbecleanedandberecycledbacktotheboring.

c）Boringdrill

i）Thedrillshallbeproperlypositionedtoassurethatnodisplacement&tiltingmovementscanoccur.Thesurveycontrollinesshallbemarkedontheframesothatduringconstruction,thesurveyworkcouldbeeasilyobserved&recorded.

ii）Thechoiceofdrillingaugershouldbemadedependinguponthesoiltobeexcavated.Normallyashellaugerwillbeused,whileintheeventofhardermaterial,thespiralaugershouldbeused.

iii）Initialdrilling:

starttheslurrypump&turnplatetoletthemachinerevolveidlingforsometime.Whentheslurryissufficientlyfilledintotheboring,thedrillingcanstart.Thesilt&claystratumcanbedrilledfast,thesandstratumwillbedrilledatalowerspeed.Theslurrydensitycouldbe1.05-1.10g/cm3，theviscosityshouldbe18-20s.Nointerruptionduringdrillingisallowed.Ifthereisanystoppageofdrilling,thetime&reasonshouldberecorded&theslurryshallbemaintainedsoastoholdupthesidesoftheboring.

d）Rocktypechecking&theboringcleaning&acceptance

Whenthepileexcavationhasbeendrilledtoitsdesignedbearingstratum,theConsultantwouldbeinvitedtocheck&confirmwhetherthedepthoftheboringandthedepthoftherockfoundationaresatisfactoryasperthedesignrequirement.Whenapprovalisgiven,theboringwillbecleaned.Duringtheboring,thedrillingdebriswillbeclearedoutbytheflushingactionoftheslurrythatispumpedtothebaseofthepileandthenisfilteredintherecoveryplantduringthedrillingprocess.Inorderthatthebottomoftheboringismaintainedascleaned,priortolengtheningthedrillingpole,thedrillwouldbekeptidlingworkfor2-3minutesuntilallthedebrisinsidethedrillingpolesarecleanedoutalongwiththewashingliquid.

Whenthefinaldepthisachieved,theboringshallbewasheduntiltheinput&theoutputslurryareatthesamedensity.Beforeplacingoftremieconcrete,thebottomdebrisshouldbechecked&a2ndcleaningoftheboringmaybeperformedifnecessary.

e）Treatmentofslurry

Theslurrypumpedoutshallbepumpedintoalargeprecipitationbasinmadeofblocks.Thesiltedsandwillbeclearedoutbymeansofsandremovingmachineuntilthesedimentcontents&theslurrydensityisincompliancewithrequirements.Theapprovedslurryaftercheckingbyslurryviscometercanbere-usedforconstruction.

Thesurplussedimentwillbetemporarilystoredinthebasinuntilitisfull,thenthewholesedimentcouldbeclearedout&bedisposedofinthedesignatedpits.

f）Fabricationofthesteelreinforcementcage

Thesteelreinforcementcageshouldbefabricatedintheworkshopasperthedesigneddrawings.Foreachcrosssection,theoverlapareaofthemainbarsshallnotbemorethan50%ofthesectionarea.Theoverlaporjointareashouldbemadeinastaggermanner.

Spacerwillbefixedat2.5mintervalsalongthemainbarssoastoassurethecorrectthicknessofconcretecover.Duringstorage,handling&deliveryofthereinforcementcages,propermeasuresshallbetakentoavoidanydeformation&rustingofthereinforcementcages.

g）Installationofthetierod

Inordertoavoidanyeffectstotheconcreteinsidethepiles,thetierodendsshallbeplacedclosetotheinternalsideoftheconcretecage.Whentheconcreteispoured&beforetheconcretehasset,thetierodwillbeinsertedintoitsdesignedcentralpositionofthepiles.Thetierodsshallbeplacedhorizontallywithoutdisplacementssoastointroduceotherstresses.Duringbackfilling,attentionshallbegivensoastoavoidanydamagetothetierods.Afterbackfilling,allthetierodsshallbeadjustedtocreateauniformstresstothewholetierodsystem.

h）Concreting

TheconcretingwillbedonebymeansofΦ250mmtremiepipeswitheach1.5-4.0mlong&connectedwithflanges.Thepipejointsshouldbefittedwithδ=5mmrubberringtokeepthemwatertight.Eachpipejointendshallbemaintainedvertically&beplaceddownthepileshaftslowlytoavoidanytwisting.Theupperpartwillbefittedwithfunnelofabout2m3,whenthefirstfunnelofconcreteispoured,thetremiepipeshouldbeburiedintotheconcretearound0.8mdeep.

Accordingtothesiteconditions,theready-mixedconcretewouldbepumpedintothetremiepipefunnel.Beforeplacingofthefirstfunneloftheconcrete,aconcretecorkof220mmdia,270mm