INDUSTRY GUIDE FOR FORMWORK CONSTRUCTION INDUSTRY SOUTh AUSTRAlIA JUNE 2012
INDUSTRY GUIDE FOR FORMWORK
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INDUSTRY GUIDE FOR FORMWORK
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Awdt This guidance material has been developed by a tri-partite industry working party and has involved extensive consultation with industry and other special interest groups. The contribution of the following organisations is acknowledged:
• • • • • • • •
Built BuiltEnv Environ ironsPt sPtyL yLtd td Construction, Construction,Forestry Forestry,Mi ,Mining ningandE andEnergy nergyUnion Union Hansen HansenYu Yunck ncken enPty PtyLtd Ltd Hindma Hindmarsh rshA Aust ustral ralia ia Mitcon MitconForm Formwor workPt kPtyL yLtd td Newg Newgen enF For ormw mwork orkers ers SystemF SystemForm ormwork workPt PtyLt yLtdd Safe SafeW Work orkSA SA
Diaa t :
• Bovi BovisL sLen end dLea Lease se • WorkplaceHea WorkplaceHealthan lthandSafet dSafetyQueen yQueensland sland • Safe SafeW Work orkSA SA Phtaph t :
• • • •
Construction, Construction,Forestry Forestry,Mi ,Mining ningandE andEnergy nergyUnion Union Mitcon MitconForm Formwor workPt kPtyL yLtd td SystemF SystemForm ormwork workPt PtyLt yLtdd Hindma Hindmarsh rshA Aust ustral ralia ia
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PrefAce ThisIndustryGuideforFormworkisbasedontheSouth AustralianOccupational Health, Saety and Welare .GiventhatSouthAustraliaislikely Australiaislikely Regulations 2010 .GiventhatSouth toadopttheharmonisedlegislation, toadopttheharmonisedlegislation,itisrecommended itisrecommended that readers of this document also become familiar with
therequirementsoftheWorkHealthandS therequirementsoftheWorkHealthandSafety(WHS) afety(WHS) legislation once it comes into effect.
SafeWorkSA,incollaborationwith SafeWorkSA,incollaborationwithmembersofthe membersofthe ConstructionIndustry,hasprod ConstructionIndustry,hasproducedthisguidan ucedthisguidanceto ceto provideemployers,self-employed, provideemployers,self-employed,andemployeeswith andemployeeswith practical advice on preventing injury to anyone engaged in erecting and dismantling formwork and associated equipment.
AspartoftheSAConstructionIndustryOHSCommittee’s AspartoftheSAConstructionIndustryOHSCommittee’ s strategytoaddressareasofhighrisk,itwasagreed that the creation of appropriate industry guidelines for erecting and dismantling formwork and associated equipment was a priority. It was further agreed that the codes of practice and
guidelines,existinginotherstates(Que guidelines,existinginotherstates(Queensland, ensland,New New SouthWalesandVictoria)andoperatingeffectively,could be utilised in the development of a similar resource for
SouthAustralia.
Information provided in this publication has been prepared by industry representatives and is designed to prevent injury to anyone engaged in erecting and dismantling formwork and associated equipment. This publication is correct at the time of printing and is provided as general information only. In utilising general information about workplace health
andsafety,thespecicissuesrelevanttoyourworkplaceshouldalwaysbe considered. Theremaybeadditionalrisksataworkplacethathavenotbeenspecically addressedinthisguidance.UndertheSouthAustralianoccupational healthandsafetylaws,suchrisksmustbeidentiedandcontrolmeasures implemented and reviewed to eliminate or minimise exposure to these risks. Usersofthisguidancematerialshouldbeawarethatitisbasedoncurrent knowledge and construction methods within the industry and is not intended to exclude other methods or processes that can also meet the required safetystandards.Thisindustryguide,onanyparticularaspectoflegislation, is not to be taken as a statement of law. To To ensure compliance with your legalobligationsyoumustrefertotherelevantActs,Regulationsand ApprovedCodesofPractice.Thispublicationmayrefertolegislationthathas ApprovedCodesofPractice.Thispublicati onmayrefertolegislationthathas beenamendedorrepealed.Whenreadingthispublicationyoushouldalways refer to the latest laws.
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Th ti thi idt id a t: • givepract givepractical icaladvic adviceabo eaboutwa utwaysto ysto aa xp t i aiatd with w ii th a, ti, atati ad diati w • contributet contributetothe othedevel development opmentof of itt hih tadad a w i th tti idt that a di t t pati at th wpa. It i t itdd that thi id appid t i-t hi.
conTenTs 1. Itdti
1.1
Falls from height – limitations of harness
4.3 Stripping formwork 4.3.1 General formwork stripping 4.3.2 Safe work method statements 4.3.3 Certication prior to stripping 4.3.4 Exclusion zone 4.3.5 Drop stripping 4.3.6 Bond reduction 4.4 Crane and other load handling systems 4.4.1Loadingmaterialsduringformworkconstruction 4.4.2 Slinging loads 4.4.3 Lifting gear 4.4.4 Lifting formwork materials 4.4.5 Lifting lugs 4.5 Use of ladders
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systems for formwork activity 2. Di
2.1 Safedesign of buildingsinrelation toformwork 2.1.1 ‘Buildability’ 2.1.2 Materials 2.2 Formwork systems 2.2.1 Safe formwork design and verication 2.2.2Formwork design certication requirements
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5 5 5 6 6 6
2.2.3 Documentation
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2.2.4 Design variations 2.2.5 On-site coordination and verication
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3. cdiati ad adiitati
3.1 Work program 3.2 Housekeeping – access and storage 3.2.1 Access and egress 3.2.2 Material storage 3.2.3 Rubbish storage and removal 3.2.4 Storage to minimise manual task risks 3.3
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9 9 9 9 9 9
Training
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4. W t
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4.1 Formwork erection – traditional systems 4.1.1 Foundations 4.1.2 False deck 4.1.3 Erecting frames 4.1.4 Installing bearers 4.1.5 Installing joists 4.1.6 Fall protection from the formwork deck 4.1.7 Edge protection on the formwork deck 4.1.7.1 Formworkconstructionzonephysicalbarriers 4.1.7.2 Edge protection on completed decks 4.1.8 Laying a formwork deck 4.1.8.1 Getting started – safe access 4.1.8.2 Typical work system for a leading edge 4.1.8.3 Laying a form ply deck 4.1.8.4 Laying a metal deck 4.1.9 Cantilever requirements 4.1.10 Penetrations 4.1.11 Working zones forformworkersand others 4.1.12 Changing oor levels 4.2 Formworkerection–modularformworksystems 4.2.1 Basic modular systems 4.2.2 Training
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5. spia qit wa ad
5.1 5.2 5.3
Bracing for wind loading Access platforms Lifting methods
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6. spia qit ip ad p 22
6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8
Access and egress Work platforms Trailing screens and platforms Climbing the form Training Health issues and amenities Engineering issues Emergency issues
7. fai t
7.1 Hazard controls 7.2 Prevent the object from falling 7.3 Perimeter containment screens 7.3.1 Screen height at building step-ins 7.3.2 Perimeter screen gaps 8. Hath
8.1 Noise 8.2 Dust and atmospheric contaminants 8.3 Manual tasks
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APPenDIces
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Appendix 1: Denitions
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Appdix 2: Taii
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Appendix3:Sampleengineer’scerticationletters
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Appdix 4: ctti hit
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Appendix5:Samplestructural(pre-pour)certicate
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Appdix 6: Dt d i w t
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1.
1.1
Itdti
sysTems for formWork AcTIvITy
Formworkisthesurface,supportsandframingusedtodenethe shapeofconcreteuntiltheconcreteisself-supporting(see AS 3610- 1995 Formwork or Concrete ). Forthepurposesofthisguide,theformworkassemblyincludes: • theformsonwhichconcreteispoured • thesupportstowithstandtheloadsimposedbytheforms and concrete
Whenerecting,alteringordismantlingformwork,theuseofthe following systems is not recommended: • travelrestraintharnesssystemstopreventafall • fallarrestharnesssystemstoarrestafall. Travel restraint harness systems are impractical for formwork as:
• thecontouroftheleadingedgeisconstantlychanging,requiring the length of the travel restraint line to be continually adjusted
• anybracingaddedtoensurestability. Hazardsassociatedwiththeerection,alterationordismantlingof formwork include:
• • • • • • • • •
fAlls from HeIgHT – lImITATIons of HArness
• multiplelanyardanchoragepointsmayberequired • thegreaterthenumberofworkersbuildingtheformworkdeck, the greater the likelihood of lines becoming tangled.
fallsfromheight fallingobjects formworkcollapse(before,duringandafterpouringofconcrete) slipsandtrips noise dust manualtasks sharpedgesonmetaldecks sunglare.
Toproperlymanagerisks,apersonmust: • identifyhazards • assessrisksthatmayresultbecauseofthehazards • decideoncontrolmeasurestoprevent,orminimise, the level of risk
• implementthecontrolmeasures • monitorandreviewtheeffectivenessofthosemeasures. Controlmeasuresmustbeimplementedinanorderofpriorityand beforeworkcommences.Figure1belowillustratesthehierarchy of controls which represents the order of priority for controls where
Fall arrest systemsareprohibitedundertheSouthAustralian
Occupational Health, Saety and Welare Regulations 2010 (OHSW Regulations)insituationswherethereisinsufcientdistance availabletopreventapersonhittinganobject,thegroundoranother surface,otherthanaverticalsurface.Forexample:
• Whenerecting,alteringordismantlingformwork,theremaybe insufcientfreefalldistanceunderneaththeworkingarea, resultinginafallingpersonstrikingtheground,aframeorother obstruction prior to the fall being arrested.
• Afallingpersonmayrequireafreefalldistanceinexcessof 6mforthefalltobesafelyarrestedbyaharnesssystem.In somesituations,thisdistancecanbesubstantiallyreducedby the use of shorter lanyards and/or higher anchorage points.
• Theanchoragepointdesignloadrequiredforfallarrestsystems isrelativelyhigh.TheOHSWRegulationsspecifythateach anchorage point of the system must have a minimum capacity of
15kNforonepersonfree-falling. • Theerectionofformworkframesusingfallarrestharnesses requires the user to regularly disconnect from and reconnect to
anchoragepoints,requiringtheuseofadoublelanyard.
there is a risk that a person could fall.
Di ad pai
Eliminatetherisk during the design and planning stage.
Wh thi i t patia, 1 t:
Wh thi i t patia, 2 t:
Workonasolidconstruction withsafeaccess/egress,edge protection,openingscoveredetc.
Usefallpreventionsystems e.g.temporaryworkplatforms, scaffolds,perimeterguardrails, elevating work platforms.
Wh thi i t patia, 3, thenlevel4ornally,level5controls: l 3–useworkpositioningsystems, travel restraint systems l 4–usefallarrestorcatchplatforms l 5–useladdersoradministration
controlse.g.nogoareas,permitsystems, safe work systems.
Figure 1 Hierarchy o controls – Controlling the risk o alls
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cid th wi i a ha t:
• Ariskassessmentaddressingthehierarchyofcontrolsshouldbe usedtoidentifysatisfactoryalternativestoaharness–basedon fall prevention measures.
• Implementingtheuseofsolidworkzonebarriersisone effectiveengineeringsolution.Refertosection4.1.7ofthisguide for further information.
• Trainingisrequiredbeforeapersonusesaharness.Fortraining requirementsundertheSouthAustralian Occupational Health, Saety and Welare Act 1986 (OHSWAct),pleasereferto Appendix 2.
2.
Di
Undersection23a‘Dutiesofdesignersandownersofbuildings’of theOHSWAct,designersofbuildingstobeusedasworkplaceshave obligations for workplace health and safety. 2.1
sAfe DesIgn of buIlDIngs In relATIon To formWork
2.1.1
‘bidaiit’ Figure 2 – Flat oor and temporary access as all protection or deep oor beams
Buildingdesigners,includingengineersandarchitects,must considerthe‘buildability’ofastructureorbuildingwiththeobjective of producing a design that minimises the risk of injury during construction.
• Reducecantileveredoorsections. • Planformanualtasks.Considerationshouldbegiventothe
Thedesignofthenalconcretestructuremayhaveamajoreffecton theeaseofformworkconstructionandconsequently,onthesafetyof peopleduringconstruction.Generally,amorebasicandsimplenal
suitability of the design of different formwork systems that will -
table forms
concrete structure is safer to erect.
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systems with lighter weights of materials to be handled
Aformworkdesignershouldbeconsultedduringthedesignofany building to provide input on ways to minimise the risk of injury arising from formwork activities.
reduce manual handling risks such as:
- methodsofformworkerection,alterationanddismantling -
improved access and egress for workers and movement of materials and equipment
- methodsformovinglargeandheavycomponents,materials
The following design measures could be considered to minimise
and equipment i.e. making allowances for a crane and other
exposure to risk of injury during the construction of formwork:
mechanical lifting devices to be used.
• Reducevariationsintheoordepthi.e.constructaoorso that it has one consistent depth. Decks that are a consistent
2.1.2
matia
depthareeasiertoerectthanvariabledepthoorsandreduce theriskofinjury.Deeperbeamsintroduce‘dropdowns’into theoor,creatingtripandfallhazards,andrequiremoreworkto
Allmaterialsandequipmentusedinformworkconstructionmust betfortheintendedpurpose,meetdesignspecicationsandbe designedtoconformtorelevantAustralianStandards.Equipment
construct and strip after pouring.
must be manufactured in accordance with a quality assurance
• Wherebeamformsareessential,lightweighttemporaryaccess across the beam recess must be provided to prevent injury to
workersfromsteppingintotheformduringconstruction(see Figure 2above). • Reducethenumberofcolumnsrequiredandwherecolumnsdo exist,eliminatecapitalsanddropdowns. • Utiliseprecastcolumnsandbeams.Thiscanreducetherisks associatedwithxingreinforcement,erectingandstripping columnformworkandpouringconcreteon-site.Workactivities carried out in a factory environment are generally lower risk.
systemthatensurescompliancewiththedesignspecication. Evidenceverifyingthatformplysheetsandtimberbearersconform toAustralianStandardsshouldbekepton-site.Suchevidencemay include:
• apurchaseorderwhichdetailsthespecicationsofthe form ply sheets ordered
• formplysheetsbeingmarkedinaccordancewithAustralian Standards(see AS/NZS 2269.0:2008 Plywood-Structural- ). Specifcation 5
Ifalternativeproducts,otherthantimberareused,anengineer
− the geographical location of the construction site will have a
bearingontheseverityofwindonthestructure.Wind
should verify that they are adequate for purpose.
generally has less effect in built up or hilly areas 2.2
formWork sysTems
− AS 1170.2 Structural Design Actions – Wind Actions
speciesfourdifferentterraincategoriesthatshouldbe
InAustralia,formworksystemsaregenerallydesignedto:
taken into consideration by a formwork designer as well
• AS 3610 – Formwork or Concrete • AS 3600 – 2009 Concrete Structures.
asbasicwindspeedsfordifferentzonesinAustralia [practicallyallareasofSouth AustraliafallunderRegionA (normal)].
2.2.1 Safeformworkdesignandverication
Adesignerofformwork,eitheraformworkdesigneroranengineer (seeAppendix1fordenitions),isresponsibleforoverseeingthe safe design of the complete formwork structure. This includes
designoftheformworksupportstructure,theformworkdeckand connection details.
Whenspecifyingthedesignoftheformworksystem,aformwork designer must allow for all expected loads applied during the three
phasesofconstructioni.e.duringformworkerection,duringconcrete pouring and after concrete pouring is complete until the structure is self-supporting. This includes loads applied by:
• • • •
theformworkdeck,supportingmembersandformworkframes anyfalsedecksthatmaybeprovided concretepouringtechniques(i.e.concreteskiporpump) theconcretepour,whichincludesboththeweightofthe concreteanddynamicfactorsapplied,includingtheconcrete pour rate and pour sequence
• workersontheformworkdeckandfalsedecks • stackedmaterials • crane-liftedmaterialsonboththecompleteandincomplete formwork deck
• environmentalloads,includingforcesduetowaterowing aroundtheformwork.Rainandrunoffcanhaveadetrimental effect if not considered by a designer
• wind,asdetailedin AS 1170.2:2011 Structural Design Actions – Wind Actions: − wind loading will vary depending on:
Refertosection4‘StructuralDesignandDocumentation’of AS 3610 Formwork or Concrete for further details on formwork load calculations. 2.2.2 Formworkdesigncerticationrequirements This guide considers two types of formwork systems: ai and -ai.Aformworkdesignermaycertifyabasicformwork
system,whereasonlyanengineermaycertifyanon-basicformwork system.
Whilethisguiderecommendsthatonlyanengineermaycertifya non-basicformworksystem,itisrecognisedthatacompetentperson experiencedinformworkdesignanddocumentation,suchasa formworkdesigner,mayperformthemajorityofthedesignwork. Forbothbasicandnon-basicformworksystems,certicationshould conrmthattheformworkmeetstherequirementsof AS 3610 – 1995 Formwork or Concrete and the construction drawings. This certicationshouldalsoconrmthatotherformworkandproject documentationdetailedinsections2.2.3ofthisguide,havebeen completedasrequiredfortheproject.Sampleengineer’scertication lettersareprovidedinAppendix3. bai w t
Forthepurposesofthisguide,abasicformworksystemisthe formworkforaoor,wallorcolumnandincludes: • standardformworkframeswhichhaveaknowntestedloading
- the size of form
capacity and are spaced at no more than the recommended
- the nature of the form
distancesapartforanormaloorthicknesswithbearers,joists
- wind speed
and form board on top of them
- wind resistance(e.g. screens) - wind direction
− windloadingonverticalforms,particularlyforexternalwalls, columns,freestandingshutters,bladewallsandany platforms that may be subject to uplift − vertical elements should be fully braced prior to and during stripping until such time as the construction provides adequate support against wind loading
− shadeclothusedonscreens,signageandoutsidescreens will increase the effective wind loading of an open structure
• speciallymanufacturedanddesignedformworksystemswith proprietary formwork components and rated load calculations in
linewiththemanufacturers’specications. Abasicformworksystemislimitedbythefo llowingconditions: • theheightoftheformworkmaybeuptoamaximumof6mto thesoftofthenewoorfromthesupportingoor • wallsandcolumnsmaynotbegreaterthan6mfreestanding fromtheooronwhichtheformworkwillbesupportedtothetop surface of the concrete
• anyback-proppingisexcludedfrombasicformworksystemsand istobecertiedbyanengineer. 6
Eitheraformworkdesignerorengineermaycertifyabasicformwork system.Whereanyoftheseconditionsareexceededorbackproppingisinvolved,thesystemistobeclassiedasanon-basic formworksystemandmustbecertiedbyanengineer. n-ai w t
Formworksystemsthatexceedthedescriptionofabasicformwork systemare,forthepurposesofthisguide,categorisedasnon-basic formworksystems.Forthepurposesofthisguide,onlyanengineer may certify:
• thedesignofanytemporaryorpermanentformworkstructures categorised as non-basic formwork systems
• anyback-proppingusedforeitherbasicornon-basic formwork systems.
Non-basicformworksystemsincludeformworkstructuresforany oor,wallorcolumnhigherthan6m,orthreeframes,orthreetimes the least base width of the scaffold. 2.2.3
Dtati
The extent of documentation required for any structure may vary depending on the complexity of the formwork and supporting structure design and the conditions in which it is to be constructed. The documentation requirements outlined below are provided as
aguideonly,forsituationswherethereisacomplexconstruction processatheight,thatisconsideredtobehighrisk.Itisexpected that some elements of documentation may be reduced or omitted for some more basic and lower risk construction applications. fw dawi
Formworkdrawingsexplainthegeneralarrangementoftheformwork plans,elevationsandsections,identifyingandlocatingallmembers and components including bracing.
Anengineershouldnominatethefollowingonthedrawingsorother documentation:
• maximumallowablepointloadingtobeappliedandany additionalproppingrequirementsatanyspecicloadingarea • componenttypesandspacing • maximumjackextensions • bearerandjoisttimbertype,dimensionsandspacing • propsizesandmaximumextensions • methodsfortyingthestructuretogetherandspacingbetween ties(ifrequired) • formplysize,thicknessandgrade. Whereeccentricloadingistobeappliedto‘U-heads’(i.e.single bearersarepositionedtoonesideoftheU-head),theformwork drawings must state that this is permitted.
oth w dtati The following information should be included in the formwork documentation:
• anynecessarypreparationofthefoundationsuchaslling, compaction and drainage
• anyfootingdesignassumptions,suchasfoundationmaterial description,safebearingvalues,limitationsonsettlementduring erectionofformwork,placementofconcreteanddismantlingof formwork.Referencetoinformationsourcessuchas geotechnical reports may also be included
• footingdetails,suchastypeandsizeoffootings,levelofsoft, concretemixdesignstrength,reinforcement,specication anddetailsofsitellingorcompaction,andprecautionsagainst washouts
• sufcientdetailstofullydescribeimportantorunusualfeatures oftheformworksystemdesign,includingdesignassumptions, particularlythoserelatingtostrength,stabilityandstiffness • theareasoftheformsdesignedtocarrystackedloads,together withthemaximumallowableload,andtheminimumstrengthof concrete to be achieved prior to materials being stacked
• Safeworkmethodstatementsaddressing: − the erection and stripping of the formwork assembly − methods for securing single or multiple props
− methodsforeldadjustmentoftheformspriortoand during concrete placement
− verticalpourratesinmetresriseperhour,includingtherisks and implications of exceeding vertical pour rates
− sequenceofconcreteplacement,includingdirectionof intendedpouronrakingorslopingsurfaces(e.g.carpark ramps and minimum elapsed time between adjacent
placements) − wrecking strips and other details relating to stripping of the forms
• certicationofnon-proprietaryequipment • referencetodocumentationforproprietaryitems • whererequired,locationofweepholes,vibratorholes,clean-out holes and inspection openings
• acceptancecriteriaforsingleuseformwork. Pt dtati
Otherprojectdocumentationshouldincludethefollowing information:
• detailsoffallandedgeprotectioni.e.perimeterscaffolding • locationofanymandatoryjointsandanyspecialproceduresfor locating other joints
• detailsofanyinserts,waterstops,speciallyformedshapesor penetrationstobeconstructed,thelocationanddetailsofwhich are critical to the serviceability of the permanent structure
• informationonanyarchitecturalorstructuralcomponentdetails to be cast into the structural concrete 7
• detailsofthecamberingofanyslabsorbeams • informationaboutanypermanentformworksystems,together withlimitationsondeectionsandanyspecialrequirementsfor their erection and concreting • limitationsontheuseofthepermanentstructurefortherestraint of formwork • minimumstrippingstrengthortimes,strippingproceduresand requirements for health and safety • detailedinformationontheeffectofpreorpost-tensioning procedures on the formwork and any special procedures to be adopted in the stripping of formwork • detailsofback-proppingthatmayberequiredandminimum timeintervalsbetweenconcretepours,includingrequirements for propping of any composite construction • requirementsfortheminimumnumberoflevelsofsupports relativetothetypeofformwork,thetimingandsequenceof oorpropping,andtheanticipatedtimebetweenconstructionof subsequentoorsformultistoreystructures. 2.2.4
Di vaiati
Allformworksystemdesignvariationsmustbecheckedbyaformwork designerforabasicsystem,oranengineerforanon-basicsystem. Thevariationsmustbecertied(inwriting)ascomplyingwith AS 3610 – Formwork for Concrete or whether they need to be altered in accordance with written directions to comply with AS 3610 . Potentialvariationsmayinclude: • thenumberofformworkframesundertheformworkdeck • typesandnumberofbracesorpropsotherthanindicatedon the formwork drawing • • • •
typesand/orquantitiesoftiesontheformworkstructure spansonmemberssupportingtheformworkdeck back-proppingsystemsspeciedbyanengineer connectionsbetweentraditionalformworkand modular formwork.
2.2.5 On-sitecoordinationandverication
Complexprojectsrequireconstantandvigilantcoordinationbyan experiencedmanagementandsupervisoryteam.Withproperly scheduledandcoordinatedactivities,sub-contractorsareabletocarry outtheworkinanorderly,safe,andmoreproductiveway. Effectivecoordinationandtechnicalaccuracyalsorequirethat
• materialsandcomponentsusedon-sitecomplywiththeformwork designspecications,drawingsanddocumentation • damagedorexcessivelywornmaterialsandcomponentsarenot used,butareidentiedandsentoff-siteforrepairoraredestroyed. Theformworkstructure’scompliancewithitsdesignmustbeveried anddocumented.Aconstructionchecklistmaybeusedasaguidefor thisprocess(refertoAppendix4forasamplechecklist).However, relying solely on a checklist does not necessarily verify compliance with relevantAustralianStandards. Thedesignvericationanddocumentationprocessmaybedelegated toa‘competentperson’who,ifnotanengineerorformworkdesigner, musthavetheexperience,trainingandknowledgetoperformon-site inspectionsoftheformworksystem(refertoAppendix1fordenitions). The competent person must be:
• experiencedinformworkconstruction • competentininterpretingdrawings • abletocertifythattheformworkstructuresatisesthedetails ontheformworkdrawings,specicationsandanyotherformwork documentation. Shouldthecompetentpersonon-sitenotbeaformworkdesigneroran engineer,thecompetentperson: • mayonlyverifythattheformworkstructurecomplieswiththe designer’sspecicationsanddrawings • maynotauthorisevariationstothedesign • mustprovideanyconstructionchecklistreferralstoanengineer in writing • mustprovidewritteninstructionstotheformworksupervisorfor any remedial actions that need to made to the formwork system prior to the concrete pour • mustensurethatanyremedialactionrequiredhasoccurredprior totheconcretepour,includinganyitemsreferredtoanengineer. Pre-pourinspectionmustfocusonsuchmattersas: • thelatestversionofstructuralandformworkarrangement drawings and details submitted • correctspacingofframes,propsandtimbers • correctjoistandbearersizes,andloading • acceptablejackextensions • adequatebracingtoensurestability.
formwork,projectandvariationdocumentationarereadilyaccessible on-site.
Pre-pourinspectionsarethelastreasonableopportunitytoensure compliancewiththeformworkdesignspecications.Suchinspection records form an important part of the site quality control system and
Wheneffectivesitecoordinationisnotimplementedoraconstruction teamdoesnothaveaccesstoessentialtechnicalinformation,the potential for failure increases.
mustbesigned-offbyanengineer,formworkdesignerorcompetent personfollowingthenalpre-pourinspection.Asamplepre-pour structuralinspectioncerticateisprovidedatAppendix5.
Vericationoftheformworkstructure
c dt i w yt
Aneffectivequalitycontrolsystemmustbeimplementedforthe construction of formwork. The system should ensure that:
Appendix6illustratessomeofthemorecommondefects that are likely to occur in a formwork system. The list is intended to
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give guidance to a competent person and is not considered to be
exhaustive.Inanyindividualcase,theimportanceofitemsmayvary and only a competent person can assess their relative importance.
3.
cdiati ad adiitati
3.1
Work ProgrAm
Therisktoaperson’shealthandsafetymustbeconsideredwhen designingaworkprogramforerecting,alteringordismantling formwork.Considerationshouldbegivento: • edgeprotectionrequirementsandensuringthesearedesigned and constructed in a timely manner to be safe to use
• sequencingworktoensurethatsufcienttimeandresources are allowed for each work activity
• coordinatingtradestoallowworktobecompletedfreefrom obstruction. 3.2
HousekeePIng – Access AnD sTorAge
Formworkconstructionresultsinaconstantlychangingwork environment,withrestrictedaccessthroughframesandformwork supports,oftenwithlargevolumesofmaterialandwaste.Forthis reason,itrequiresongoingmonitoringofhousekeepingpracticesto maintain a safe and productive workplace. Include housekeeping as an essential aspect of every job whether
itbethroughworkinstructions,regularinspectionoftheworkplace, or site/task induction training. Instructions should include time and resources for the progressive clean up of work areas to prevent
rubbishandredundantmaterialsfrombecomingatriphazardandto allow safe access for mechanical aids. 3.2.1 A ad
TheOHSWRegulationsrequirethattherebeclearaccessto andfromtheworkplaceinaccordancewithDivision1–Access and egress.
Clearaccessisimportantforthesafemovementofmaterials, equipment and anyone on-site. Designated access ways should be
providedandanyoneon-siteshouldbedirectedtousethem.Access waysmustbekeptclearofanyrubbish,plantormaterials. Insomesituations,greenhazardtaping/buntingorothervisual methods can clearly show where access ways are located. This is particularly important where access is required through formwork frames.
Emergencyaccessandegressmustbeprovidedtoallpartsofthe
3.2.2 matia ta
TheOHSWRegulationsrequiresafestackingandstorageofplant andmaterialsataworkplace,asdetailedinDivision15–Storage. Materialsmustbestoredinawaythatminimisesmanualtask hazards,triphazardsandthepotentialforhazardsfromfalling objects.SmallercomponentssuchasU-heads,couplers,baseplates and‘Z-bars’shouldbestoredinlabelledmaterialboxes,markedwith safeloadlimits(SLL). Wherepracticable,frames,formplysheets,bearersandjoists should be strapped in bundles or stacks and be located away from
theedgeofthedeck,topreventmaterialsoranyoneaccessingthem from falling.
Wallformsshouldbestackedinsuchawaythattheycannotslide, orrotateawayfromthesurfacetheyareplacedagainst.Anengineer shouldverify,inwriting,thatasurfacetobeusedforstackingforms iscapableofwithstandingtheimpactofallimposedloads,including windloading.Ifpurpose-made‘A-frames’arenotavailablefor storingwallformswhennotinuse,itispreferabletolaythemat ontheground,ratherthanleaningthemagainstotherstructures. Timbers,orothereffectivemeansofsupport,shouldbeusedunder forms where slings are to be used for lifting. 3.2.3 rih ta ad a
Rubbishstorageandremovalforformworkmayincludethe provision of rubbish skips and wheelbarrows that are moved as work
progresses.However,rubbishskipsmayonlybepositionedwhere the supporting structure has adequate strength to support the total weight of the bin and its likely contents. 3.2.4 sta t iii aa ta i Incorrect material delivery and storage practices can create
signicantmanualhandlingrisks.Safeworkpracticesthatcanassist in minimising these risks include:
• ensuringthatformworkmaterialsaredeliveredascloseas practicable to the job
• designinganddesignatingasmallsectionoftheformworkdeck as a loading platform for ply and other components
• ensuringmechanicalaidsareusedtohandleloadswherever possible
• storingloadsontrolleystominimisedoublehandling,oron raised platforms to minimise manual lifting from ground level
• havinganadequatestoragespaceorlaydownareastosafely store materials/equipment and to minimise double handling.
workplace. The following situations should be considered:
• • • •
stretcheraccessandegress peoplecarryingtoolsandequipment useofstairs provisionoftwomeansofegressatalltimes. 9
3.3
TrAInIng
Anyonewhomaybeexposedtoworkplacehealthandsafety risks resulting from formwork construction must be provided with
informationandtrainingthatisspecictotheformworksystemthat is being used. Training and information should include details of:
• theformworksystem,components,tasksandactivities • thewaythemanufacturerordesigneroftheformworksystem intendedittobeerected,installed,used,moved,alteredor dismantled
• therangeofhazardsassociatedwiththeformworksystem, controlmeasurestominimiseexposuretotherisks,thecorrect use of controls and how to ensure controls are maintained
• anyspecialrequirementstoundertakeorparticipateinspecic tasks or activities
• anysafeworkmethodstatements,includingtheuseof
4.
W t
4.1
formWork erecTIon – TrADITIonAl sysTems
TheOHSWRegulationsdescribewhatmustbedonewherethere isariskapersoncouldfallinDivision13–PreventionofFalls. Thelegislationalsorequiresthatahazardidenticationandrisk assessmentbeconductedand,wherenecessary,safeworkmethod statements documented.
Formworkactivitiesmustcomplywithregulatoryrequirements fortheerectionofscaffolding.Formwork,likescaffolding,mustbe erectedsafelyandsystematically,andbetiedinprogressivelyto stabilise the structure.
Apersonmustbeprovidedwithaworkingplatformatleast 450mmwide(i.e.twoplanks)evenwhenthepotentialfalldistance is less than 2 m. It is not acceptable for a person to work from a single plank or bearer.
mechanical aids and devices
• theuseandmaintenanceofequipment,includinganyspecic conditionsandprohibitionsonitsuse.Wherenecessary, referenceshouldbemadetooperator’smanuals • anyspecialsafetyinformationneeded,suchassafety precautions for working under certain conditions including hot
workorconnedspacework • personalprotectiveequipmentrequirements,including instructionsfortting,use,cleaning,maintenanceandstorage • theavailabilityandcontentofthisindustryguidancedocument.
Irrespectiveofwhichframingsystemisused,workersmustalways use working platforms that are two planks wide as a minimum.
Whereapersonistoinstalljoists,thiscanbeachievedusingatwoplankworkplatformfromunderneath,allowingtheverticaldistance between the formwork deck and the false deck to be increased. This
isillustratedinFigure3below.
FortrainingdetailsrefertoAppendix2.
>2.0 <2.0
vArIAble
Figure 3 – Worker erecting ormwork on two planks
10
The false deck should be designed to have adequate strength to
4.1.1 fdati
Formworkmustbeerectedonastablebasetopreventtherisk ofcollapse.Suspendedslabsmustbeabletosafelysupportloads thatmaybeappliedbytheconcretepour,workersandcrane-lifted loads etc.
Baseplatesmustbeprovidedunderpropsandstandardson formworkframesunlesstheproporstandardhasanintegralfoot,or an engineer documents that a base plate is unnecessary.
Soleboardsdesignedtosuitthegroundconditionsmustalsobe usedunderpropsandstandardsonnaturalground,unlessan engineerstatesotherwise.Framesandpropsmustbelocatedon asoundbasethatwillnotsubside,failorwashaway.Theprincipal contractor is responsible for providing all information on ground conditions to the engineer or formwork designer.
support:
• anyonerequiredtostandonthedeck • materialsthatneedtobeonthedeck • anymaterialsorworkersthatshouldhappentofall. The deck must be able to withstand:
• apointloadof2kNdistributedoveranareaof100x100mm (2kNisapproximatelyequivalenttoamassof200kg) • auniformlydistributedloadof2kPa,whichisequivalenttoa mass of 200 kg per m2.
Whenconsideringthedesignofthedeckforerecting,alteringor dismantlingformwork,theweightofthefalsedeckandanyadditional live loads must be applied to the analysis of the formwork support structure. The height between the false deck and the pouring deck should allow
4.1.2 fa d
In situations where a deck is being installed at a height that would require a person to stand at a height of 2 m or more to install bearers
andjoists,acontinuous‘falsedeck’shouldbeprovided(seeFigure 4below).Thisisafulldeckthatisthesameareaastheoorbeing formedbutupto2mbelowthetruedeck.Asindicatedinsection4.1 above,thedistancebetweenthefalsedeckandthetruedeckcanbe increasedwhereaworkplatformisused.However,thefalldistance from the work platform to the false deck must not exceed 2 m. The false deck should be continuous both inside and between
formworkframesandtypicallyconsistsofformply,scaffoldplanksor modularplatformsections.Aprotectedaccessopeningcanbeleftin the deck for lifting in materials.
comfortable access for a person during stripping. 4.1.3 eti a
Anyoneinvolvedinerectingformworkframesmustbetrainedto dothissafely.Apersonsupervisingtheerectionofformworkframe systemsmustbeacompetentperson(asdenedinAppendix1). TheOHSWRegulationsprovidetherequirementsfortrainingand responsibilities of workers performing a class of high risk work. In cases where scaffold equipment is used as a formwork support
structureanditispossibleforapersonorobjecttofall4mormore fromthescaffold,theOHSWRegulationsrequireapersontohold: • aBasicScaffoldinglicence(SB)toerectproprietaryframes
Gap not to exceed 225 mm
or
• anIntermediateScaffoldinglicence(SI)toerecttubeand ttingscaffold. Traineesarepermittedtoperformscaffoldwork,providedtheyare under the direct supervision of a competent person who holds the scaffolding licence necessary for the task.
Formworkframesshouldbeerectedinaprogressivemannerto ensureboththeinstaller’ssafetyandthestabilityoftheoverall structure.Bracingistobeattachedtotheframesassoonas Figure 4 – A alse deck
The use of a captive platform is preferable to lapped planks because a captive system cannot be accidentally dislodged and its
constructionalsominimisestriphazards.Lappedplanksmayonly be used if they are secured against uplift and slippage. The false
deckshouldbeconstructedsuchthatnogapexceeds225mmin width and gaps only exist where a vertical member of a frame passes through the deck.
practicable. The risk of a fall from edges of formwork frames during
theirerectionishigh.Inthissituation,itisnecessarytoinstalledge protection on the frames as they are erected.
Conventionalformworkframesincludediagonallyhingedbracesthat crossinthemiddle.Whilethesebracesarenotconsideredtobe suitableedgeprotectionforacompletedformworkdeck,basedona riskassessment,theymayprovidereasonablefallprotectionduring frameerection.Suchfallprotectionexistsonlywhenbracesare installedimmediately,andinaprogressivemanner.
11
Astheheightofformworkframesincreases,thereisagreat erneed toprovidelateralstabilitytotheframestructure.Allframingmustbe carried out so that it complies with on-site design documentation and
anymanufacturer’srequirements. 4.1.4 Itai a
Whenpositioningbearers,installersmustbelocatednomorethan 2mfromtheoororthefallarrestingplatformlocatedimmediately belowthem.Forexample,bearerscanbeliftedontothetopofthe
Oneexampleofaworksystemthatmaybeusedtodothisis as follows:
The joists are lited by the workers and spread on top o the bearers into their approximate fnal positions whilst standing on a lower work platorm. The platorm below the deck must be positioned at a comortable height or handling joists (without introducing manual task risks) and not greater than 2 m rom the alse deck.
formwork frame by a person standing on a work platform erected
4.1.6 fa ptti th w d
withintheframeandnomorethan2mfromtheoororfalsedeck locatedimmediatelybelow(seeFigure5below).
Continualmodicationoffallprotectionmeasuresisnecessary
Bearersmustbepositionedsuchthattheywillnotfallfromthe
changing.Oneofthebiggestchallengesistoprovideadequatefall
frames. The common methods of ensuring this are to place the
protection on the leading edge of the formwork deck.
bearersinU-headsontopoftheframesandalsobyensuring cantileversareminimised.Whereonlysinglebearersareplacedin theU-head,thebearermustbeplacedandxedcentrallyinthe U-headunlessaformworkdesignerorengineerstatesotherwise.
Wherethereisonlyoneleadingedge(i.e.theotheredgesare providedwithscaffoldingedgeprotection),theprovisionoffall protectionisrelativelystraightforward.However,wherethereare
4.1.5 Itai it
Whereafalsedeckisprovidedat2morlessbelowformworklevel, joists may be spread on the bearers with the worker standing on the false deck. If the height of the formwork deck being constructed is
morethan2maboveacontinuousdeckorsurface,joistsmustbe spreadfromaworkplatform,atleasttwoplankswide,andlocated within 2 m of the surface underneath the deck being constructed
(refertoFigure5).
during formwork construction because the structure is constantly
multiple leading edges and/or the deck is not at one consistent
level,theprovisionoffallprotectioncanbedifculttoimplement. Designersofbuildingsarethereforeencouragedtodesignoorslabs thatareoneconsistentthickness(refertosection2.1.1‘Buildability’). Leadingedgeandperimeterprotectionmustbeprovidedonedges where the potential fall distance is 2 m or more and a person is not
preventedfrombeingwithin1.8moftheedge.Controlmeasuresare requiredwhereapersoncouldfall,fromanyheight,ontoanobject suchasframes,reinforcingsteelorarubbishskip.
<2.0
>2.0
Figure 5 – Setting U-heads, bearers and joists rom a two-plank platorm 12
Acceptable solid work zone barrier with ‘No-Go’ zone below
Figure 6a – General view
4.1.7 ed ptti th w d 4.1.7.1
fw tti z phia ai
Aphysicalbarriershouldbeprovidedandmaintainedtoseparatethe formworkworkzonefromotherworkers.Thisbarriermustberigid, capable of maintaining its integrity in an upright position and capable
ofsupportingsignageifrequired(seeFigures6aand6babove). The use o ags and tape or unsupported barriers is not acceptable.
Wherethedesignoftheformworkiscomplexandtheproleof thedeckisconstantlychanging,constructionofleadingedge protectionmaycreatemorehazardsthanitwouldcontrol.Insuch cases,itmaybeimpracticaltoprovideedgeprotection,asanyone installing the edge protection would be exposed to the risk of falls. In some situations perimeter edge protection must be installed.
Examplesinclude: • wherethereisachangeindeckheightalongthesideofthedeck beingconstructed,(i.e.adropdownforabeam)andnojoistsor form ply have yet been installed at this different height
• wherealeadingedgeistobeleftunattendedandaccessonto thedeckisrequiredbyanyoneotherthanformworkers(i.e.the formwork deck has not been barricaded off and marked with
‘keepout’signs). 4.1.7.2
ed ptti ptd d
The most effective means of providing edge protection on a completed formwork deck is to install perimeter scaffolding.
Scaffoldingiserectedpriortotheformworkand,therefore, prevents workers falling from the completed deck. The advantages
ofthissystemarethatedgeprotectionforinstallersofthenal perimeterformplysheetsisalreadyinplace,thereisnorequirement toinstalledgeprotectionontheperimeter,andnoexposuretoarisk of falling.
Figure 6b – Fixing detail
Insomeraresituations,itmaybeimpracticaltoprovideperimeter scaffolding.Insuchcases,edgeprotectionmustbeinstalledandthe work system used for this installation must include a control measure against the risk of a fall.
Theuseofharnesssystemsisdiscouraged,becauseitdoes not provide an adequate level of protection from injury and is an impractical control for the risk of a fall from height in formwork
erection(refertosection1.1ofthisguide). Insomesituations,edgeprotectioncanbesubstitutedwithan alternativemeasure,providedthismeasurepreventsapersonfalling fromtheedge.Onealternativeistheprovisionofabarricade,1.8m fromtheedgewithclearlyvisible‘keepout’signs. Furtherguidanceonstanchions,guardrails(handrails)andmid railsforminimumstrengthandrigidityisspeciedin AS 1657 Fixed platorms, walkways, stairways and ladders – Design, construction and installation. Wherescaffoldingisover4minheight,onlylicensedandauthorised scaffoldersmayerect,dismantleoralterthescaffolding.Any scaffolding components that are temporarily removed must be
replacedattheearliestopportunity.Anygapsbetweenacompleted oorandscaffolding,thatmayexistaftertheformworksupport systemisremoved,mustbecoveredwherethereisariskofa person or materials falling through. 4.1.8 4.1.8.1
lai a w d gtti tatd – a a
Afterthesupportingframes,bearersandjoistsareinposition,the rstessentialconsiderationinlayingaformworkdeckisthatall building work conducted at height requires some type of perimeter
protection.Thesecondessentialconsiderationisthat,forfall prevention,workersmuststayawayfromaleadingedge.Howthese essential elements are achieved is determined by the builder. 13
Therststepinlayingoutaformworkdeckistoprovidesafeaccess andaheavydutybaytoloadandstorematerials,particularlyapack offormply,attheformheight.Successfulsolutionswillbepartially guidedbythesiteitself,thesizeofthejoborthecontractor’s preferredsystem,andmaybeanengineeredsolution,ascaffold solutionoraformworksupportsystemsolution.Eachhasadvantages and disadvantages. eid ti
sad ti
Scaffoldsolutionsmaybemoreexibleintheirarrangementand would normally require a lower initial capital investment than engineered solutions. They are generally more suitable for smaller
jobsandrestrictedsites.Scaffoldsystemloadingbaysarema nually erected,withtheplatformareaandhandrailsbeinginstalledat height,increasingtheriskoffallsduringerection. The load carrying capacity of scaffold-based systems is generally
Generally,engineeredsolutionsareeconomicaltoassemble, disassemble,useandmaintain,andmaybedesignedforahigher load-carryingcapacity(withsufcientsupportframecapacity).They are more suitable for larger projects with more site room.
Engineereddeckunitsarepositionedandliftedbymechanical aids,suchasmulti-purposetoolcarrier,forkliftorcrane,thus reducing the risk of injury from manual tasks. Drop-in hand railing
systemsareeasilyinstalledatgroundlevel,reducingtheriskoffalls during erection.
However,engineeredsolutionsgenerallyhaveahighercapitalcost todevelop,manufactureorpurchase.Engineeredsolutionsareless exiblebecausetheremustbeaclearaccesswayof450mm.This limitsavailablespaceforstorageofmaterialsonthedeck(seeFigure 7below).
lowerthanengineeredsolutions,beingheldwithintheallowable limits for AS/NZS 1576.1:2010 Scaolding Part 1: General Requirements .However,scaffoldingmaybespecicallydesigned forhigherloads.Workplatformsdesignedforhigherloadsmust prominentlydisplayasignindicatingtheSLL. Scaffold-basedsystemsaregenerallymoreadaptableinallowing forincreasedsizeofstoreditems,notnecessarilybeinglimitedto thesizerequirementsof2400x1800mmformplysheets,whilst maintainingthenecessary600mmminimumaccesswidth. fw ppt t ti
Packsofformplysheetsmaybeplaceddirectlyonthejoistsofa formworksupportsystemundercertaincircumstances.Asection of the formwork support system may be a nominated loading area providing:
• thenominatedloadingareaiscertiedbytheengineeror formwork designer
• themaximumSLLoftheareaismarkedontheformwork drawings,togetherwithadditionalproppingrequirements
Figure 7 – Engineered loading bay. Note: Drop-in handrails in place, liting eyes, orklit slots, and built-in bearers
14
• anynecessaryadditionalpropsareinstalledandinspectedprior to loading
• aperimeterscaffoldisinplaceforfallprotection • theloadingareaissafelyaccessiblefromaperimeterscaffoldor other safe access structure
• alljoistsandbearersformingpartoftheloadingareaare adequatelysecuredinpositiontopreventafall,asdescribedin section4.1.8.3ofthisguide • layingtheformplydeckproceedsasdescribedinsection 4.1.8.3ofthisguide • astartingpointforlayingthedeckisclosetotheformply stack so as to minimise worker exposure to the risks of injury from manually handling the form ply sheets. 4.1.8.2
5. Coverorprotectallpenetrationsleftbehindtheleadingedge. Coversmustbesecurelyxedandclearlysignedtoindicatethey areprotectingapenetration(seesection4.1.10). 6. Nailorotherwisesecureformplytothejoistsassoonas practicable.
• Iftimbershavenotbeenxed,edgeprotectioncomplying withOHSWRegulations2010(Division13–Preventionof Falls),mustbeerectedleadingawayfromthesidesofthe leading edge.
• Onlypersonnelinvolvedintheconstructionoftheformwork maybelocatedintheformworkconstructionzone.Anyone not involved in this process should be excluded.
• Theleadingedgemustbefreeofoil,sawdustand obstructions to reduce the likelihood of slips and trips.
Tpia w t a adi d
The following work system may be used to construct the formwork deck for typical multi-level construction. The work system is
specicallyintendedforsituationswheretheverticaldistance belowthedeckbeingconstructedisgreaterthan2m,butwiththe use of false decks may be used irrespective of the distance to the
oorbelow.
4.1.8.3
lai a p d
Aformworkdeckmustbelaidinaprogressivewaythatincludesa method of preventing falls below the deck. This control measure is particularly important in situations where a false deck has not been
providedwithin2mbelowthelevelofthedecktobelaid,andthe potential fall distance is therefore greater than 2 m.
1. PlacebearersontheU-headsoftheformworkframesfromthe workingplatformprovidedimmediatelybelow.Securebearers topreventmovement,i.e.bynailingto,orwedgingin,the U-headsbeforejoistsareplacedontop.Noeccentric(uncentred)loadsshouldbeappliedtotheU-headsunless specicallyallowedbytheformworkdesigner.
400 mm
≤
1.8 m
≥
2. Placejoistsonthebearersinaprogressivemannerfromthe work platform located directly below the area to be worked
on,andspacedat450mmcentres(maximum)orsothatthegap betweenjoistsdoesnotexceed400mm.Securethejoists against any movement should a worker fall onto them.
1.8 m
≥
3. Secureanycantileveredbearersandjoiststopreventupliftor dislodgement prior to anyone working on them.
4. Layoutformply,orotherdeckmaterial,progressivelyas describedinsection4.1.8.3.Whereverpossible,thedirectionof theleadingedgeshouldbeperpendiculartothejoists,i.e. paralleltothebearers(referFigure8). • Formplyshouldbeplacedonthejoistswiththeinstaller located behind the sheet as it is positioned whilst standing on the previously laid sheet or work platform provided. If this is
doneconsistently,shouldapersontriporstumbletheywould fall onto the sheet and not from the leading edge.
• Planningshouldtakeintoaccounttheoptimumpositionfor theloadingbay,ordirectionofformplyplacementsothat laying out of the sheets starts at the loading bay where the
formplyisinitiallystacked,reducingtheneedformanual handling and carrying sheets.
Figure 8 – Maximum spacing o timbers around worker where alse deck is over 2 m below
Whereafalsedeckhasnotbeenprovidedwithin2m,formplymay only be spread on the joists where:
• aminimumoffourjoistsat450mmcentres(400mmgaps, totalling1.8m)arelocatedonbearersnexttotheperson, andthejoistsextendforatleast1.8mallround(seeFigure8). Therefore,intheeventofafall,thepersonwillfallontothejoists and be prevented from falling further
• layingtheformplysheetscommencesfromtheperimeter scaffolding or other edge protection that has been provided at
theperimeteroftheformwork,e.g.attheloadingbaywherethe form ply is stacked
• theformplyislaidinfrontofthebodysothatifthereisa stumble,thefallislikelytobeontopofthesheetsbeinglaid
15
• joistsarexedtopreventsidewaysmovement.Insome situations,theremaybeapossibilityofapersonfallingthrough thejoistsifthejoistsspreadastheperson’sbodymakescontact
sectionsareunavoidable,theformworkdesignerorengineer must consider the potential for people and stored materials to
causecantileverstopivot.Formworkdesignsmustindicatewhere
with them during a fall. This is more likely to be a potential
cantilevers are to be positively secured so that the weight of a person
hazardwhentheperson’sfallisinthesamedirectionasthe layofthejoists.Fixingjoiststopreventsidewaysmovementwill
or material does not cause the section to pivot.
minimise this possibility.
4.1.10
4.1.8.4
Ptati
Anypenetrationwherethereisariskthatapersonoranobjectcould
lai a ta d
fallthroughmustbecoveredorsecurelyguarded.Openpenetrations,
Ametaldeckshouldbelaidinaprogressiveway.Whereafalsedeck
suchasstairwellvoidsorpenetrationstoallowforservices,create
has not been provided within 2 m below the level of the deck to be
hazardsforanyoneonaformworkdeck.Apersonmayfallthrough
laid,metaldecksmayonlybelaidwheretheuseoffallprevention systemshavebeenprovided.Worksystemsfollowingthehierarchy ofcontrolsmustbeused.Examplesincludeelevatingworkplatforms, scaffolding,personalfallprotectionsystemsandanti-glaremeasures (refertoFigure9).
largerpenetrations,sustaininjurybysteppingintoasmallerpenetration,
4.1.9 cati qit
AS/NZS 4576: 1995 Guidelines or Scaolding requires that the design of cantilevered scaffolds and the adequacies of their supportingstructuresmustbeveriedforcompliancewiththe relevant requirements of AS/NZS 1576.1 Scaolding Part 1: General Requirements byacompetentperson,suchasanengineerwith experience in structural design.
Cantileveredbearers,joistsandplysheetscanbehazardouswhen left unsecured. The weight of a person standing on the cantilever
maycausetilting,resultinginthepersonormaterialfalling. Formworksystemdesignersshouldminimisetheuseofcantilevers wherepossible.However,insomesituationswherecantilevered
oranobjectmayfallthroughtheopeningontoworkersbelow.All penetrations must include cast-in metal mesh as a backup system.
Themeshshouldhaveasmallaperture(e.g.50x50mmmeshsize orsmaller),andbemadeofmaterialcapableofwithstandingthe potentialimposedload.Meshprovidedoverlargepenetrationsmay requireengineeringcerticationtoensureitcanwithstandpotential loadsincludingpeople,equipmentandmaterials. Whereholesarecutinthemeshforservicestopassthrough,the holeshouldbecuttotheproleoftheservicesothatmeshremains covering the penetration.
Ungradedplywoodcoversarenotadequatebecause: • thecovermaybeindistinguishablefromotherpiecesofply • itmaybedifculttodetermineiftheplywoodisproperlysecured • securedplywoodcoverscanbeunsecuredtogainaccessand subsequently may not be re-secured.
Figure 9 – Sae Work System or laying metal deck (Note:Fallpreventionsystems)
16
exap i
“DAnger PeneTrATIon beloW” SLL where required
Dynabolt,orsimilar anchorage
100 mm (min)
100 mm (min)
Floorslab
Floorslab
Min17mmthick
50mmmeshcastincentrally
Figure 10 – Example o acceptable penetration protection
Plywoodcoversmustbe: • • • • •
Penetrationsarealsohazardousbeforethedeckislaid.Joists placed up to the edge of the penetration must be secured so that the
structurallygradedandsound aminimumof17mmthick paintedabrightcolour non-slip markedwiththewords‘DAnger PeneTrATIon beloW‘.
timbers cannot spread if a person falls on them. 4.1.11 Wi z w ad th
Theformworkconstructionzonemustbesufcientlylargetoensure
Thecovershouldbermlysecuredtotheconcreteanddesigned forpotentialloadsthatmaybeapplied.RefertoFigure10foran acceptablepenetrationprotectiondesign.Beforestrippingformwork, ensure the penetration that will be exposed is securely covered and protected.
Zone for oTHer Workers
* r e i r r a b l a c i s y h P
that formwork areas are clearly separated from other work areas.
A‘formworkconstructiononly’zonemustbemaintainedbehind theleadingedge.Thiszonemustbeclearlydemarcatedbysignage andameshbarrier.Figure11illustratesthe‘otherwork’zone,the formworkzoneandthearearetainedasedgeprotection(fourjoists spaced1800mmbeyondthelaiddeck).
This distance may vary depending on work requirements formWork consTrucTIon Zone
*Reer to 4.1.7.1 Formwork construction zone physical barriers Figure 11 – End view o deck showing working zones
17
4.1.12
Changingoorlevels
Formworkdecksmaynotbeatacrosstheentireoor,dueto deepbeamsor‘dropdowns’(sometimescalled‘capitals’)around columns.Suchvariable,unevenoorsintroducetripandfallhazards duringformworkerection.Itispreferablethatthesehazardsare eliminatedatthedesignstage(seesection2.1.1‘Buildability’). Fallandtriphazardssuchasthesearemosteffectivelymanaged by ensuring that lower level formwork supports and decks are progressively constructed before work commences on the higherlevel areas of the deck. 4.2
formWork erecTIon – moDulAr
4.2.2 Taii
Workersinvolvedintheerectionofmodularformworksystemsmust be trained in the safe erection and dismantling of the system and the
inspectioncriteriaforcomponents,particularlyfordefectsthatwould preclude their use. The modular system supplier or designer should provide written instructions for the erection and dismantling of the system. Instructions should include safety instructions equivalent to those detailed in this guide.
Trainingbythemodularformworksystemsupplierisencouraged.For trainingrequirementsrefertoAppendix2.
formWork sysTems 4.2.1 bai da t
Thebasicprinciplesdiscussedinsection4.1ofthisguideon traditional systems apply to the erection of modular formwork
systems.Althoughtheerectiontechniqueandmemberdimensions mayvarygreatlybetweentraditionalsystemsandmodularsystems, the principles of maximum potential fall distance and gap width at the working level are applicable:
• thewidthofanygaponaworkinglevelisnottoexceed 400mmunlessafalsedeckhasbeenprovidedwithin2m of the working level
• workingplatformsusedformodularsystemsmustalsohave aminimumwidthof450mm.
4.3
sTrIPPIng formWork
Strippingformworkcanbeoneofthemosthazardousphasesof concrete construction.
Whilefallingobjectsaretheprimaryhazard,theremayalsobefall hazardsasaresultofoor,scaffoldorformworkcollapse,aswellas manualtaskhazardsfromapersonworkinginawkwardpostures, repetitivehandlingofmaterials,orlimitedtaskvariety. Workersmustbeinformedoftherisksandbeadequatelytrained, sothatstrippingoperationsarecarriedoutinanorderly,progressive manner,asoccurswithformworkerection. 4.3.1 ga w tippi
Bothmodularandtraditionalformworksystemsmustbedesigned to comply with the loadings and general principles of AS 3610: Formwork or Concrete.
To reduce the risk of injury when stripping formwork/fa lse work:
Traditional formwork systems are sometimes used adjacent and
• erectacatchdecknomorethan2mbelowtheworkarea • suitablybarricadeandsignpostthestrippingarea (withbarriermeshasaminimum).
connectedtomodularsystems,particularlyforunusuallyshaped areas.Wherethisisthecase,theformworkdrawingsshouldshow anyessentialconnectionordesigndetailsandbecertiedbyan engineerorformworkdesigner.However,componentsfromone proprietary type of formwork system should not be used as integral parts of other modular formwork systems unless the designer of the modular system states in writing that this is permitted.
Modularformworksystemsareoftenmanufacturedfromaluminium insteadofsteelandarethereforelighterinweight.Beinglightweight, theyrequirelessphysicalefforttoerectthantraditionalsystems,and alsotheneedforrepetitivehammeringmaybeeliminated,reducing workers’exposuretotheriskofinjuryfrommanualtasks. Becausemodularsystemsarelighterinweighttheymaybemore susceptible to overturning during erection when exposed to eccentric loading factors such as wind loading etc. This is generally an issue only prior to placement of the decking on the modular support
system.Toeffectivelycontrolanyinstability,modularformwork
• installfully-deckedworkplatformsataheightnogreater than 2 m from ground level or the catch deck
4.3.2 sa w thd tatt
Onlyanexperiencedandcompetentpersonshouldpreparesafe workmethodstatementsforthestrippingoperation.Properly prepared statements are very useful as a training tool for those who will be involved in this high risk activity. The safe work method statement should detail factors such as:
• thehazardsrelatedtothestrippingprocessandanyequipment and strategies to eliminate or minimise the risks
• thenumberofpeopleinthestrippingcrew • thesequenceofstrippingactivitiese.g.detailinghowtheframes and/orothersupportsaretoberemovedandhowfarU-heads may be lowered
• whetherthesupportsystemmaybecompletelyremovedina zonepriortoremovaloftheformworkdeck,orwhetherthe
systems must be progressively braced during erection in accordance
supports are to be lowered slightly but still remain under the form
withthemanufacturer’sinstructions.
ply while it is being removed
18
• whenback-proppingisrequiredoronlypartofthesupport systemistoberemoved,howthestructuralmembersareto remain in place and/or the type and layout of members that will replace the formwork system
• anyotherspecialrequirementsinvolvedinthestrippingand or building processes e.g. checking of back-propping after post-tensioning. 4.3.3 Certicationpriortostripping
Priortocommencementofthestrippingoperation,anengineermust providewrittencerticationthatformworkcanberemoved.This certicationshouldbebasedonanengineer’sspecicationsforthe building,thestrengthoftheconcretemixandthetimeperiodthat has elapsed since the pour.
Anengineermayalsoberequiredtohaveinputintothestripping safe work method statement to ensure the concrete element
doesnotfail,andmustprovidesufcientdetailonthestructural engineeringdrawingsasrequiredbysection17‘Formwork’of AS 3600 – Concrete Structures. Documentation from the concrete supplier verifying the concrete
specicationshouldbeavailableonrequest.Aconcretesampling and testing procedure should be in place to verify that concrete
meetsitsdesignspecicationforstrippingpurposes.Guidance on sampling and testing systems for concrete is provided in
4.3.6 bd dti
Strippingofformworkmaybeaidedbyreducingthebondbetween theformmaterialandtheconcrete.Bondstrengthisdependenton thematerialcharacteristics,thesmoothnessoftheformmaterial and age of the concrete. The use of a liquid bond breaker on wall and column forms is one way of reducing the strength of the bond.
However,theuseofbondbreakeronoorformsisnotencouraged becauseofthesliphazardthatmayresult. 4.4
crAne AnD oTHer loAD HAnDlIng sysTems
4.4.1 ladi atia di w tti
Formworkstructuresarenotnecessarilysafetoacceptanyexcess loadinguntiltheyarefully-secured.Thatis,untilafterthedeckisin placewithtie-insandproppingcomplete,andanyproposedloading areacertied. Inpractice,someloadingoccursbeforeadeckiscompleted e.g. unloading pallets of ply and joists on a partially constructed
formworkstructure,tocontinuethedeck.Thisisanunacceptable and dangerous practice which could lead to a full structural collapse
ofthedeck,possiblyresultinginseriousorfatalinjury.Toensurethe integralsafetyofthedeck,materialsmayonlybestoredwhereand whenthedeckiscertiedasabletobeartheload.
AS 1379:2007 Specifcation and Supply o Concrete.
Formworkersandcranecrewsmustbemadeawareofthespecic locationsandloadsforcertiedloadingareas,andthatstacked materialsmaycreatepointloadings,whichaformworkstructuremay
4.3.4 exi z
not be designed to bear at that point.
Onlythoseinvolvedinthestrippingoperationarepermittedinan areatobestripped.Strippingareasmustbecordonedoffand
Tominimisetheriskofcollapseandotherhazards:
signs displayed to keep non-essential personnel out of the area e.g. ‘DAnger – formWork sTrIPPIng In Progress – AuTHorIseD Persons only’.
Itispreferabletorestrictaccesstothewholeoorwheresoft strippingistakingplace.Thiswouldnotonlybesafer,butalso reduces the quantity of signage and barricades required.
Whereothertradesorsub-contractorsarerequiredtoworkonthe sameoorduringthestrippingofwalls,columnsorsmallsectionsof soft,theprincipalcontractororemployermustensurethatcontrols are applied to prevent non-essential personnel from entering the stripping area. 4.3.5 Dp tippi Drop stripping is an unsafe method of work and cannot be supported by this guidance document. In cases where drop stripping is being
considered,theformworkandsupportdesign,andtheconcrete elementdesign,shouldbereviewedbythedesignerandmodiedto eliminate drop stripping.
• loadsmustnotbeplacedontheformworkdeckifthe formwork documentation prohibits loading
• formworkdrawingsmustclearlyidentifythelocationsand SLLformaximum(pre-pour)pointloadingsforthedeck.These locationsmustbespeciedbyaformworkdesignerorengineer • cranecrewsmaynotliftmaterialsontothedeckuntilthereisa designatedliftingzone • cranecrewsmustbenotiedwhenanareaofdeckisreadyto takeaload,andspeciedloadsmayonlybeplacedinthearea/s designated and placed so that they cannot fall
• deliveryofmaterialstothesiteshouldbeplannedsothatloads are not lifted onto unsecured decks
• priortoworkersleavingthesite,materialsandequipmentshould be secured to prevent them being moved by wind. 4.4.2 sii ad
Slingingandun-slingingloadsatheightisalwaysahighriskactivity. Safeworkmethodsandfallpreventionsystemsareessentialforthis activity(refertosection4.1.8.1) Adogman,orotherpersonengagedinslingingloads,mustbe provided with adequate fall protection and a safe means of access 19
when working at 2 m or more above the deck. The use of fall arrest systems for workers slinging formwork
loadsisusuallyimpracticalandisnotrecommended.However,it maybereasonablypracticabletotplatformsandedgeprotection as fall protection. 4.4.3 liti a
Guidanceontheuseandinspectionofchains,wireropesand synthetic slings is provided in the following publications:
• AS 2759: 2004 Steel wire rope – Use, operation and maintenance • AS 3775.2: 2004 Chain slings – Grade T Part 2: Care and use • AS 1353.2: 1997 Flat synthetic webbing slings Part 2: Care and use.
• Liftingboxesintendedforliftingpeoplemustbedesign registeredwithSafeWorkSAandsuitablyconstructedforother material being lifted.
• Fourchains(oneineachcorner)mustbettedtoliftboxesto maintain stability.
• Liftingboxesmustbeinspected,maintained,andinspection records kept.
• Specically-designedliftingboxesshouldbeusedtoliftsmaller components(e.g.spigots,U-heads,baseplatesandcouplers). Boxesmusthaveenclosedsidesorrobustmesh(withopenings lessthantheminimumsizeofmaterialsbeinglifted). • Loadscontainedwithinliftingboxesshouldbesecured against movement.
• Materialsmustnotbestackedhigherthanthesideofthebox unless they are adequately secured.
• Formworksupportframesmusteitherbetiedtogetheror
Basicitemsthatneedtobecheckedinclude: • liftinggearistaggedandallrelevantinformationlisted (e.g.relevantinformationforachainslingisgradeofchain, safeworkingload,manufacturer,chainsizeandAustralian Standardmarking) • liftinghookshaveoperablesafetylatches • liftingeyesandinsertsarecompatible • liftingslingsareserviceableandnotdamaged(i.e.haveno excessivewear,damagedstrands,cracks,deformationand/or severecorrosion) • syntheticbreslingsaremaintainedingoodcondition,arerated fortheloadbeinglifted,haveasuitableslingingconguration
secured with lifting slings wrapped around the load.
• Loadsofjoistsorbearersshouldbestrappedtogether before lifting.
• Taglinesmustbeusedtocontrolloadsandforms,andmust bexedtotheload,nottheliftinggear. • Formplyloadsshouldbestrappedtogetherandliftedina atposition. • Ensure,wherepossible,thatallloadsaresupportedondunnage and the load is uniformly distributed over the supporting surface.
Priortoliftinganyitems: • removeanywasteconcreteetc.fromformsoranyother materials or equipment to be lifted to ensure the waste does not
and are protected from sharp edges.
Itismostimportantthatallliftinggearincludingslings,hooks,wire ropes,pendantsandmaterialboxesareperiodicallyinspectedfor
fall onto people below
• inspectallloadscloselytoensureallloosematerialsandtools have been removed.
damage and wear. The period between inspections may depend on the severity of use with the exception of:
4.4.5 liti
• chainslings,whereinspectionsmustnotexceed12months • syntheticbreslings,whereinspectionfordamagemustbe
Chainslingsattachedtolugsorholescutintopartofaloadareoften usedtoliftbins,wall,liftwellorcolumnforms(insteadofwrapping theliftingslingsaroundtheload).Informationverifyingthestructural
undertaken before each use and full inspection at least every
threemonths.Refertosection9of AS 1353 .2: 1997 Flat synthetic webbing slings, part2:‘Careanduseforinspection items’andsection11for‘DiscardCriteria’. Documented maintenance records for the lifting gear should be
adequacy of the lifting points must be available.
Anengineermustverify: • thestructuraladequacyoftheliftinglug • themeansofattachmenttotheload(usuallyweldedorbolted).
available for inspection on-site. 4.5 4.4.4 liti w atia
• Crane-liftedloadsmustbeslungandsecuredsothattheload (oranypartofit)cannotfall. • Weightsofwall,liftorcolumnformsshouldbeprovidedon-site with formwork documentation and made available for inspection by all interested parties.
• SLLsmustbeclearlymarkedonbins.
20
use of lADDers
Laddersmustbesecuredatthetoporbase,orwhenthisis impractical,heldrmlyatthebasebyanotherperson. Wherepracticable,alternativestoladderssuchasworkplatformsor stairaccesssystemsmustbeused.Fixedorpermanentladdersmust comply with AS 1657 – Fixed platorms, walkways, stairways and ladders – Design, construction and installation .
Whereladdersareprovidedasaccesstoalivedeck: • theymustextendatleastonemetreabovetheaccessed surface,besecuredagainstmovementandbesetuponarm,
• undercuttypeanchorthatdoesnotrelyonfrictiontofunction • expansionanchorsofthehigh-loadslip,torquecontrolledtype • coilbolts.Thecorrectoperationofcoilboltsisgreatlydependent on whether they are installed in accordance with a
level surface
manufacturer’sspecications(e.g.drillingthecorrectsizedhole andapplyingthecorrecttorqueinconcreteofadequatestrength).
• theymustbeofindustrialstandardwithaloadratingofat least 120 kg
• singleandextensionladdersmustbeplacedatanangleof between70degreesand80degreestothehorizontal (‘4up,1out’rule),exceptinsomeraresituationswherethis is impractical
• singleladdersmustnotexceed6.1minlengthandextension laddersmustnotexceed7.5m. Otherissuesregardingthesafeuseofladdersinclude: • metalormetalreinforcedladdersmustnotbeusedinthevicinity ofliveelectricalequipment.TheOfceoftheTechnicalRegulator (OTR)providesinformationoncompliancewithsafeworking distances in the vicinity of live electrical wires
• nevertouchaladderthatisincontactwithelectricalpowerlines • aperson’sfeetmustalwaysbemorethan1mfromthetopof the ladder
• laddersarenottobeusedonscaffoldingorelevatedwork platforms to gain extra height
• laddersmustnotbepositionedaboveoradjacenttoopeningsor edgeswhereapotentialfallcouldoccur.Aworkplatformwith edge protection should be used instead
• laddersshouldnotbeusedinaccesswaysorwherethereis pedestrian,vehicularormobileplanttrafcunlessarisk assessment has been undertaken and other precautions have been considered
• alwaysmaintainthreepointsofcontactwhenusingladders.
5. 5.1
spia qit wa ad
Drill-intypeanchorsmayhaveaspecicinstallationtorqueset requirement to function correctly. Torque measurements should be
madeusinganaccuratelyadjustabletorquewrench.Analternative method that may be used to verify the torque could be a calibrated
‘rattlegun’.Recordsverifyingthesettingtorqueforalldrill-intype anchorsshouldbeavailableon-site.Manufacturersnormallyspecify the minimum distance from a concrete edge that an expansion anchor may be installed. 5.2
Access PlATforms
Mobilescaffolding,purposebuiltworkplatformsorelevatingwork platforms may be suitable in providing the essential safe access to
elevatedworkareasfordogmen,steelxersandconcreters.Edge protection must be provided on any access platform.
Platformsmustbedesignedtoprovidesufcientaccessandworking spaceforthenumberofpersonnelrequiredforspecictasks,and must be positioned at a height and distance from the form so as to
minimisereachingandstretchingmovementsandlimitaperson’s necessary exertion.
Concretepouringsystemsmustprovideadequatesafeworking space,withedgeprotectionprovided,forallworkers. Castorsonmobileworkplatformsmustbelockedatalltimesexcept when they are being moved.
Allplatformsmustbedesignedforstabilityandresist ancetoany sideloadingthatmaybeappliedduringaconcretepour.Lightweight aluminium scaffolding may not have adequate stability when subjected to side loading and may require additional bracing.
brAcIng for WInD loADIng
Wallandcolumnformsmustbedesignedtowithstandalllive anddeadloads,includingwindloadpriorto,during,andafterthe concrete pour. The bracing and forms must not be removed from
thecastelementuntilitissufcientlymaturetosafelywithstand potential impact loads and wind loads.
Priortostripping,anengineerorothercompetentpersonmust providewrittencerticationthattheformworkcanberemoved. Bracingmustbedesignedtosuititsapplicationandveriedbythe designer(refertosection2.2.1).Bracingelementsmustbedesigned and installed to resist both positive and negative wind generated
loads.Bracinganchorsshouldpreferablybecast-intypeor‘throughbolts’thatextendthroughbothsidesoftheanchoringmedium. Drill-inanchorsofthefollowingtypemaybeused,providedtheyare installedinaccordancewiththemanufacturer’sinstructions:
5.3
lIfTIng meTHoDs
Wallandcolumnformsmayonlybeliftedwithapositivelifting system,suchasliftinglugsorbywrappingliftingslingsaround theformsuchthattheformcannotslipoutoftheslings.Purpose designedliftinglugsmustbeusedwhereverpracticable(referto section4.4.5). Anengineermustprovidedocumenteddesignsforwallandcolumn formliftingpoints,andthedesigndocumentationshouldbeavailable on-site.Whereliftinglugsareattachedtotheform,anengineermust specifythexingorwelddesign,andthemanufacturermustensure and certify that the attachment or weld complies with the design requirements.
21
Formingliftingpointsbycuttingholeswithoxy-acetylenetorchesis unacceptable and must not be used as:
• • • •
6.
theloadcarryingcapacitycannotbeguaranteed itmaydifculttoattachliftinggear positioningoftheholemaybeinaccurate theformmaybedamaged.
spia qit ip ad p
• specifyandprovidesafeworkmethodstatementsformanual handlingofshuttersandothercomponents,e.g.theuseof cranes to lift shutters and provision of safe access for workers attaching slings to shutters
• ensureadequateventilationandlightinginallworkareas • provideadequateamenitiesforworkersgiventhatslipform operations often continue for extended shifts
• alwaysuseHotWorkPermitsforslipformandjumpformsystems • ensuresufcientreextinguishersareprovided • ensureemergencyprocedures,includingfortheretrievalofan injured or incapacitated person from any work area located
Thissectionappliestoslipforms,jumpformsandcrane-liftedforms that incorporate working platforms and enclosed cells in which people are required to work.
Slipformsandjumpformsaretermsgiventoself-climbingformwork systemsspecicallyintendedtoconstructconcreteservicecores, walls and columns in high rise buildings and other concrete
withinthestructurearedeveloped,implementedandtrialled. It is acknowledged that it may not be practicable to provide an access system and working environment on a jump form or slip
formthatisofthesamestandardaselsewhere.However,anyone incontrolofaproject,taskorworkersmustcomplywiththeir obligationsundertheOHSWAct.
structuressuchassilosandchimneys.Inslipforms,theclimbing is usually carried out continuously during the concrete pour which
maybecompletedtofullheightinonepouringoperation.Withjump forms,theclimbingisdoneinsteps,liftingthecompleteformunitto thenextlevelfollowingeachconcretepour.Theterm‘climbingform’ isalsousedtodescribeeitheraslipformorjumpform.Climbing operations are usually powered by hydraulic rams or electric motors connected to climbing feet or screw shafts.
Slipformsandjumpformsusuallyconsistofanumberofdecksand mayalsobettedwithtrailingscreensthataresuspendedfromthe form.Aswithperimeterscreens,trailingscreensmay: • provideedgeprotection • preventmaterialsfromfalling • providesupportforworkplatforms,oracombinationof these uses.
Notwoslipformsorjumpformswillnecessarilybeidentical,astheir designwillbebasedonthesizeandcongurationofthestructureor building under construction. The work systems and layout of some crane-lifted forms may also be similar to those associated with slip forms and jump forms. This may be the case for crane-lifted forms provided for the inside of lift
shafts.Whilemostoftheinformationinthissectionappliestoslip formsandjumpforms,someoftheprinciplesmayalsoapplyto crane-lifted forms.
Whendesigningandoperatingthesetypesofformsystems,the following issues must be addressed:
• providesafeaccesstoallareasandworkplatforms • controlrisksassociatedwithworkingatheight • developsafeworkmethodstatementsandusingthemtotrain workers in the safe operation of slip and climb form systems
• providesufcientworkingspaceandheadroom
22
6.1
Access AnD egress
Accesstoslipformandjumpformsystemsma ybeprovidedina variety of ways including one or more of the following:
• • • •
personnelandmaterialhoistsonthebuilding permanentstairsystemsinthebuilding atrailingstairsystemsuspendedfromtheslipformorjumpform atrailingladdersystem.
Atrailingstairsystemispreferableto aladdersystemasitiseasier toascendanddescend,andemergencyevacuationisgenerallysafer and easier on a stair system. The access area between the trailing
accesssystemandthebuildingmustbeclearoftriphazardsand thereshouldbenogapsexceeding50mmwidebetweenplatforms. The formwork designer must ensure that a trailing access system is designed for additional loads that could be applied in an emergency evacuation situation. The design must ensure that not only the
strengthoftheformsystemitselfisadequate,butalsotheformwork structure safely supports any applied loads from the access system.
Atrailingstairaccesssystemshouldbedesignedforalo adof atleast2.5kPaunlessthedesignerspeciesotherwise.Where thedesignerspeciesalesserliveloadthan2.5kPa,thefollowing applies:
• asignstatingthemaximumloadlimitmustbexedtothe stairs in a visible position
• writtenproceduresmustbeimplementedtoensurethetotalload limit is not exceeded.
Laddersmustbesecuredinplaceandbeplacedatanangle between70and80degreestothehorizontal,wherethisispractical. Accessopeningsforladdersonworkingdecksshouldbeprovided withtrapdoorsthatareclosedwhennotinuse,easilyopenedfrom above,anddonotcreateatriphazardonthedeck.
Accesswaysshouldbekeptfreeofmaterials andrubbishtoprevent objects falling to the level/s below. 6.2
Work PlATforms
Division13–PreventionoffallsoftheOHSWRegulationsspecies requirements for work platforms. These requirements also apply to
6.3
TrAIlIng screens AnD PlATforms
Trailing screens can provide edge protection and a means of preventing falling objects. They can also be designed to support
lower,suspendedworkingplatformsforrepairingorpatching concrete,andtoprovideaccessforanyoneclimbingtheform.The formworkdesignerwillneedtospecicallyaddressanddocumentall
slipformsandjumpforms.However,thefollowingpointshighlight specicissuesthatmayapply:
issues for which the trailing screen system is designed. The design
• Whenplacingsteelorpouringconcreteintoaform,controls
• Theremustbeasuitabledesignloadingforanyplatformson thetrailingsystem.Asaguide,platformsmustbedesignedto supportaminimumloadof2.5kPa.Adesignermayreduce
must be implemented that prevent a person falling into or from the form. The risk of this is higher when the form is greater
must address the following:
than225mmwidepriortoplacementofreinforcingsteel. Workersmustalsobeprotectedfromtheriskofbeingimpaled onprojectingreinforcingbarsorotherobjects.Suitablecontrols
this if the number of people is strictly limited and controls are
implementedon-sitetoensurethespeciedloadisnot exceeded.Ifthedesignloadislessthan2.5kPa,thismustbe statedindocumentationkepton-siteandsignsmustbexedto
may include edge protection on the internal side of the working
platform,orreinforcementmeshtemporarilyplacedontopof theform,enablingthesteeltobefedthroughthemesh(see Figure 12).
the platforms stating the maximum load permitted in kilograms.
Sitepersonnelmustbemadeawareofandcomplywiththe maximum loading that applies to the trailing platform.
• Strategiesmustbeimplementedtoadequatelycontrolthe riskfromfallingmaterials(seesection5forfurtherguidance). • Allplatformsmustbesecuredtopreventupliftoranyother unplanned movement.
• Ariskassessmentofaformsystemmustincludetheneedfor, anduseof,laddersandedgeprotection.Thesystemmustmeet therequirementsoftheOHSWRegulations. • Apersonmustnotrideontrailingplatformswhiletheplatforms are being crane-lifted. If access or work is required whilst a
cranesupportsthetrailingplatform,anotherworksystemmust be devised. This could involve another crane with a regis tered
Figure 12 – Mesh used as all protection on wall pour
workbox,oraseparateaccessscaffoldsystem. • AnyworksystemchosenmustcomplywiththeOHSW Regulationsandincludesafeworkmethodstatementsbasedon riskassessment,withriskcontrolstrategiesbasedonapplication of the hierarchy of control.
• Thedesignandconstructionofplatformsmustincludepositive xedsecuritysothatjammingormovementcannotoccurunder eccentric loads e.g. where work platforms have a trailing screen
ononesideandaresupportedbyabuildingparapetontheother, uplift may occur from wind loading or where a platform is not
levelandisunsecured.Ifthisoccurs,theplatformmayjamor otherwisemoveundertheunbalancedload,causingaperson to fall.
6.4
clImbIng THe form
Climbingisusuallycarriedoutusingaseriesofclimbingdevices set up to lift at the same time and at the same rate. If the lifting system is not properly synchronised the form may become wedged
onthestructure,orstructuralmembersmaybeoverloadedand become unstable.
• Whereindividualcellsofaformareclimbedatdifferenttimes,
There should be a systematic approach to ensure that the form
edge protection must be provided separately on each cell.
remains within level tolerances during the climbing process. The
• Safeworkmethodstatements,developedforallhigherrisk aspectsofslipformorjumpformsystemsandaccesssystems, will assist in ensuring safe systems are implemented and provide a sound training aid for workers engaged in this activity.
system may be automated or may rely on operators stopping each
individualdevicecontrollingtheclimbingprocess.Whicheverprocess isused,thefollowingmustbeobserved: • Asafeworkmethodstatementmustbedevelopedtotrain personnel and manage the climbing process.
23
• Onlythoseworkersdirectlyinvolvedwiththeclimbingprocess may be on the form during the climb.
• Anypotentialniporshearpointswhereapersoncouldbeinjured duringtheclimbmustbeidentiedandcontrolled. • Allobstructionsandlooseitemsontheformaretoberemoved priortoclimbing.Aninspectionchecklistand‘sign-off’procedure for this should be implemented. Items typically left on forms
includeZ-bars,ferrulebolts,insertanchors,coversand hand tools.
• Itisimportanttoensurethedifferentpartsoftheformremain level during the climbing process.
• Electricalcables,waterandotherpipedservicesshouldbe
• communicationandremoteworksystems–nopersonistowork aloneand‘buddy’systemsaretobeencouraged. RefertoAppendix2forothertrainingindifferentareas. 6.6
HeAlTH Issues AnD AmenITIes
Safeaccessandadequateventilationtoallcellsmustbeprovided inclimbingformsystems.Extendedperiodsinhotandcramped workingconditionscreateadifcultworkingenvironmentandthese issues should be considered during planning and job design. It may be necessary to specify job rotations or maximum times spent in
cells,dependingontemperature,humidity,cellsizeandtheparticular
designed and installed so that they will not catch or rupture as
activities being undertaken. Time limits and job rotation should be
the form is climbed.
considered in consultation with workers when developing safe work
Formsmustbeeffectivelysupportedatalltimesduringclimbing operations,particularlywhenremovingaformfromavertical element.Seriousincidentshaveoccurredwhenithasbeenassumed thataformissupportedfromacrane,whenitisonlyrelyingon ‘throughbolts’forsupport. Inoneincident,whentheboltswereremoved,theform-to-concrete
method statements.
Duetothenatureoftheworkandtheworkenvironment,the provisionofadditionaldrinkingwatersupplies,toiletsandamenities may also be required. 6.7
engIneerIng Issues
adhesive forces failed a short time later. The form fell while workers
The design of climbing form systems is more complex than formwork
were still standing on a platform attached to it.
systemsforoorsandincludestheconsiderationofwindloadingand otherstressesgeneratedduringclimbing.Suchformworksystems requiregreatertechnicalandengineeringinput,andmustbe classiedasnon-basic,withanengineerasthedesigner.
Thishazardappliestobothcrane-liftedformsandjumpforms, whichmustalwayshaveapositivemeansofsupport.Workersmust never be in a position where they rely on formwork adhering to the concrete surface for support.
The climbing form designer must be involved in both the design of
theformandindevelopingsafeworkmethodstatements,sothatany 6.5
TrAInIng
Slipformandjumpformoperationsrequirespecialisedworksystems andpresentuniquehazardstoworkers,requiringspecictraining
ongoing design issues occurring during form erection over the life of the building project are addressed.
Somedesignproblemsassociatedwithclimbingformsystemsmay
and specialised safe work method statements for personnel working
not become apparent until the job is in progress and system design
on the forms.
changes may be necessar y. Designers and principal contractors
Trainingandthedevelopmentofsafeworkmethodstatements, shouldinclude,butnotbelimitedto: • themaximumloadingsthatcanbeappliedtothevariousareas on the form. This would include information about areas where materials can be stored
• restrictedaccessareasandproceduresfortheinstallationand removal of edge protection
• sliporjumpingproceduresforthoseinvolvedintheseoperations • requirementsfortheapplicationofHotWorkpermits • emergencyevacuationproceduresforthoserequiredtoworkon the form
• reghtingprocedurestobeusedinemergencysituationsprior toreghtingpersonnelarrivingatthescene • anyotherspecialworkproceduresthatspecicallyapplyto workingontheform,e.g.timelimits(wheretheseapply)for working in cells or safe undertaking of manual tasks
24
must implement consultative arrangements that include regular
inspectionsoftheworksduringaclimb,andconsultationwiththose involvedintheoperationtoidentifyanydifcultiesorsafetyissues. Section2ofthisdocumentdiscussesengineeringissuesassociated withformworkingeneral.Inadditiontothoseissues,thedesigner must address the following factors for climbing systems:
• minimumconcretestrengthrequiredpriortoclimbing • allowanceforallloads,includingallliveanddeadloadsthatmay be applied to the form system such as:
− loadscreatedbyworkers,impactloadsfrommaterialslifted onto the form and concrete-placing activities − the effects of additional and eccentric loading during climbing
• themaximumallowableskewduringaclimb,andany procedurestoeitherminimisethepossibilityofthisoccurring,or rectify a situation if forms do become skewed
• anyeffectrescueproceduresmayhaveonthedesignor operationoftheform.Rescueproceduresmayrequireaccess toalllevelsoftheformandcells,eitherthroughtheprovisionof gates or by removal of panels on the form.
Inremoteareas,amorethoroughriskassessmentmustbecarried out for emergency rescue.
Whereaformcanbeaccessedusingcraneson-site,adesignregisteredrstaidboxforemergencyrescueofaninjuredand
Anyspecicriskcontrolrequirementsmustbedocumentedinthe
incapacitated person/s must be readily available and accessible at all
safe work method statements.
times while work is being undertaken.
6.8
Bothdesignersandthoseincontrolofasiteortaskmustconsider
emergency Issues
the effect the formwork design may have during an emergency
Fireextinguishers,hosesandothermeansofrepreventionand control must be provided on climbing forms in accordance with
relevantlegislation.Emergencyproceduresmustbedeveloped, documented and implemented and all personnel must receive
trainingontheprocedures.Alistofthosewhohavereceivedtraining mustbedocumentedandkept(referFigure13). The emergency procedures must include as a minimum:
• methodsforalertingworkersintheeventofanemergency • methodsandtimingforevacuatingworkersfromeachlocation or cell
• • • •
rescueproceduresintheeventofseveremedicalconditions whoisresponsibleforensuringevacuationtakesplace personnelintheemergencyresponseteam trainingrequirementsforanyoneinvolvedinrescuingothers,
response,aswellastheirongoingresponsibilityduringconstruction. Safelyremovinganimmobilisedorunconsciouspersonduringan emergency evacuation of a formwork cell needs to be considered and planned for. This may include creating emergency a ccess holes
anddoorwaysthroughdecksandscreens.Proceduresmustidentify howtoaccesslift-voidsandotherareas,includingcellswithinthe core,whichmayhavelimitedaccess. Emergencyservicescontactsmustbeclearlyidentiedandbe prominentlydisplayedon-site.Allpartieson-site,includingthe principalcontractor,sub-contractorsandworkers,mustagreeonthe nominated emergency service contacts.
where outside experts cannot be responsible for performing the rescue
• trainingintheuseofreextinguishers • evacuationmusterpointsbothonandofftheform.
Figure 13 – First aid, fre control and emergency retrieval equipment on-site
25
7.
fai t
Containmentscreensmaybesupportedbythebuildingorstructure, orbyspecicallydesignedscaffolding.Thescreenscanalsoactas
7.1
HAZArD conTrols
perimeter fall protection on a top working platform. To fully comply
Hazardsfromfallingobjectsaresignicantandcanbepresent wheneverworkersandothersareerecting,alteringorstripping formwork,whenslippingandjumpingformworkoperationsare occurring,andalsowheneverloadsareliftedoverworkareas. Anyoneincontrolofaworksite,workareaortaskhasanobligation to control any risks from falling objects where workers or any other person could be injured by a falling object during formwork activities.
Evensmallobjects,suchasboltsorconcreteaggregate,falling fromheightcancauseseriousinjury.Controlmeasuresmustaimto preventobjectsfromfallingor,ifthisisnotreasonablypracticable, prevent injury if an object has fallen.
Inparticular,whenerectingordismantlingformwork: • close-offadjoiningareastonon-essentialpersonneltoprevent objects falling on or hitting people
• erectperimetercontainmentscreensforeachpartofthebuilding from where objects could fall
• ensurecontrolmeasuresareinplacetopreventscreen componentsfromfallingduringerection,extensionorreduction of perimeter containment screening.
withtheserequirements,thescreensmustextendatleast2mabove the working surface.
Whenformworkisbeingerectedordismantledimmediatelyadjacent toscreens,theymustextendaminimumof2mabovetheworking deck/stripping area to provide a higher level of protection for the public and for those workers outside the building area.
Whenselectingcontainmentscreens,considerationmustbe given to its:
• abilitytosupportorcontainimposedimpactloads,including buildingmaterials,equipmentandwastematerials • resistancetowindloadsonthesupportingstructure • requiredfrequencyofinspection • chemicalreactivity,includingammability • ventilationrequirements(referto AS 1668.2: 2002 The use o ventilation and airconditioning in buildings – Ventilation design or indoor air contaminant control forguidance) • lighttransmissionrequirements(referto AS 1680:1976 Code o practice or interior lighting and the visual environment for guidance) • degreeofprotectionprovidedfromrainorwashing down operations
7.2
PrevenT THe objecT from fAllIng
Controlsmustbeappliedatthesourcetopreventobjectsfrom falling;thatis,eliminatetherisk.Thisisthemosteffectivecontrolto prevent injury or death caused by falling objects. Good housekeeping practices are the most effective way of
preventingsmallobjectsfromfalling.Ensureitemsarecleanedup andkeptawayfromedges,voidsandpenetrations. The recommended control measure to prevent objects from falling outside the structure is the use of perimeter containment screens. The screens are effective as a control measure from falling objects for the protection of the public in adjoining areas as well as for safety
• patternandfrequencyofxingpoints • gapscreatedbyaxingmethod. Containmentscreensmustremaininpositiontopreventany objectfallingforthefulldurationofformworkoperations–from commencingformworkerectionuntilsoftstrippingiscompleteand allmaterialsareremovedfrom,orstackedon,theoor. 7.3.1 s hiht at idi tp-i
Asstatedabove,perimetercontainmentscreensmustextendabove the formwork erection area so that materials cannot fall to the
ground,orontootherworkortrafcareas.
and protection on-site.
Wherethehorizontalsurfaceunderconstructionstepsinfromthe overallbuildingperimeter,e.g.foraplantroomonabuildingroof,
7.3
the perimeter screens must be erected to a height that will prevent
PerImeTer conTAInmenT screens
Perimetercontainmentscreensareprotectivestructuresxedto theperimeterofabuilding,structureorworkingplatform.Their essential purpose is to prevent objects and people from falling
outsidetheworkarea,signicantlyreducingtheriskofinjuryto workers and the public.
Screensshouldbeusedduringthefullconstructionprocess, especially during formwork erection or stripping. They are usually sheeted with:
• timber • plywood • metalorsyntheticmesh. 26
any materials falling to the ground from the top of the stepped-in structure.
Oneexampleofanacceptablemethodtopreventfallingobjects reachingthegroundisillustratedinFigure14.Inthisexample,the outsideedgeofthesteppedinstructureis‘W’metresfromthe perimetercontainmentscreenandtheliftheightis‘H’metres. Topreventanobjectfallingfromthetopofthestepped-instructure, orbeingejectedfromthetoplevel,andfallingtothegroundoutside thebuildingperimeter,theheightofthescreenshouldbesuchthat the angle of an imaginary line from the top of the screen to the top
stadad 950 had ai
s s e e r r t t e e m m H H – – t t h h g i i e e H H t t f i f i L L
Maximumangle 45º no-go AreA witht ptti ai t
m u m m m i i 2 n 2 n i i m m
Step-in width – W metres
Edge o “Step-in” structure
Perimeter containment screen
Figure 14 – Height o perimeter screen or protection rom alling objects on the ground at building step-in
oftheformworkplatformrailisamaximumof45degreestothe horizontal,withaminimumacceptablescreenheightof2m. Th aati th qid hiht i:
Catchplatformsmustbedesignedbyanengineertoresistimpact loadslikelytobeapplied(i.e.frombearers,formply,propsetc). Wherechainisusedtosecurecatchplatforms,itmustmeetthe requirementsofAustralianStandardswithaknownloadlimit.
s Hiht (t) = (H + 0.95) t – W t (with a ii apta hiht 2 )
Non-essentialpersonnelmustnotenterthe‘No-Go’areanexttothe
8.
Hath
step-in unless positive controls are in place to prevent anyone being
8.1
noIse
struck by falling objects e.g. catch platforms or further screening. 7.3.2 Pit ap
Topreventmaterialfromfallingbelow,gapsbetweenperimeter screensandtheformworkdeckoroormustnotexceed25mm. This can be achieved by:
• installingpermanentlyxedplycovers • installingcatchplatforms–removableshieldsthatare connectedtoscreens,withprocedurestoensuretheadjacent area is cleaned up before the shields are removed.
Coversmustbedesignedforpotentialloadings,suchasloads applied by workers and the impact loadings of falling materials.
TheymustalsobemarkedwithaSLLiftheycanbeaccessedas a platform.
Catchplatformsdeectfallingobjectsbackintothebuilding, preventingthemfromfallingfurtherdownthegap.Catchplatforms must be attached to screens by a system that ensures that they do not dislodge and fall when the screens are lifted. The system must be
sufcientlyrobusttowithstandanyworkplaceenvironmentimpacts.
Division10–NoiseoftheOHSWRegulationsdescribeswhatmust be done to prevent risks from exposure to excessive noise at work.
TheApprovedCodesofPracticeundertheOHSWActare: • National Code o Practice or Noise Management and Protection o Hearing at Work [NOHSC: 2009 (2004)] ,3rdEdition(available fromtheSafeWorkSAwebsiteatwww.safework.sa.gov.au) • AS 1270: 1988 Acoustics – Hearing Protectors . TheCodesrequireallworkerstobeprotectedfromtheriskofnoise inducedhearingloss(NIHL)duringtheirwork.Ifnoengineering solutionisavailable,eitherearplugsorearmuffscanbeused. Activitiessuchastheerectionordismantlingofformworkmay involveveryloud,metalonmetalimpactnoises,suchasusing hammersonmetal.Suchnoisecandamagehearingimmediately becauseofitshighimpulsivenoiselevel.Otherloudnoise,suchas thatcreatedwhenusingacircularsaw,cangraduallydamagea person’shearingthroughlongerperiodsofregularexposure. The use of the hearing protectors must be enforced where a risk
assessmentidentiesthemasthepreferredoptiontocontroltherisk. 27
Often,constructionsitemanagementimposesablanketuseof hearingprotectionacrossthesiteatalltimes.Forformworkactivities, protectionagainstNIHLbywearinghearingprotectorsisoftenthe
information about preventing or minimising exposure to risks that
only option.
manualtaskrisksavailablethroughwebsitesinallotherAustralian jurisdictions,andgloballyintheUK(www.hse.gov.uk),Europe (http://osha.europa.eu/en)andCanada(http://www.ccohs.ca/).
8.2
DusT AnD ATmosPHerIc conTAmInAnTs
Division17–VentilationoftheOHSWRegulationsdescribes obligationsthatmustbemetforatmosphericcontaminants,including silica dust.
Whileconcreteitselfisnotahazardoussubstance,highlevelsof silicadustcanbeproducedduringformworkprocesses.Silicadustis ahazardoussubstancegeneratedwhenpowertoolscut,grind,chip, scrape,crushorblastmaterialssuchasconcrete.Silicadustmay alsobecreated,toalesserdegree,bysweepingorcleaningwhen dismantling building equipment or during demolition work. The visibility of dust does not necessarily provide an accurate
measureofthedegreeofrisk.Highlyvisibledustcausedby earthmoving equipment on building sites or other earthworks sites is
unlikelytocontainhazardouslevelsofrespirablesilicadust.However, silicadustproducedbyotheractivitiesmaybeathazardouslevels even though it is barely visible.
Allreasonablestepsmustbetakentominimisethee xposureto silicadust.Silicadustthatisgeneratedduringformworkcanbe controlled by:
• usingdustextractionorawetprocessasadustsuppressant engineering control
• providingrespirators(asalastresort)wheredustislikelyto exceed permissible levels. 8.3
mAnuAl TAsks
In2008/09,thereweremorethan2,270workerscompensation claims in the construction industr y. These resulted in more than
$13.3millionincompensationcostsandover38,000daysoflost time.Theindustry’suninsurablecostsassociatedwiththeseinjuries wouldhaveamountedtomorethan$53million. Oftheinjuries,730(32%)weremusculoskeletalinjuriesfrommanual tasks.Thecostofcompensationfromtheseinjurieswas$5.3million (41%oftotalcosts)andmorethan17,700workingdayshavebeen lost(47%oftotallosttime).Theuninsurablecosttotheindustryto dateformusculoskeletalinjuriesoccurringin2008/09hasamounted tomorethan$21.5million. Inallitsactivitiessuchasplanning,transport,storage,erection anddismantlingofformworkandscaffolding,theindustryneedsto take into account the risk of injury from manual tasks and develop
strategiestoeliminate,orifthisisnotpracticable,atleastminimise the risks from manual tasks. The Approved Code o Practice or Manual Handling (available
fromtheSafeWorkSAwebsitewww.safework.sa.gov.au)provides 28
contribute to or aggravate work-related musculoskeletal disorders. There are also many other sources of information for solutions to
APPenDIces Appendix1:Denitions
ei
Inrelationtotheperformanceofatask,meansapersonwho– (a)isaregisteredprofessionalengineereligiblefor corporatemembershipofEngineersAustralia,and (b)iscompetenttoperformthetask. fa d
ba
Primaryhorizontalsupportmembersforaformworkdeckthatare placedinU-headsontopofformworkframes.Bearersareusually constructedfromtimberbutaresometimesconstructedfrommetal, such as in the case of some modular formwork systems.
Adeckdesignedtopreventworkersfalling2mormoreand/or provided as a working platform. f
Anobjectusedinthecastingofconcreteoors,wallsorcolumns that has part of its surface in contact with the concrete during the
c
Partofaslipform,jumpformorcrane-liftedformwhereworkersare
initial concrete curing process.
required to carry out work. The cell will generally be enclosed by all
fw di
sides and a bottom surface.
Apersoncompetenttodesignbasicornon-basicformworksystems , butmayonlycertifybasicformwork.Tocertifynon-basicformwork, theFormworkDesignermustbeanengineerexperiencedin
Certicateofcompetency
Adocumentthathasbeenissuedbyalicensingauthoritypriorto the introduction of the National Standard or Licensing Persons Perorming High Risk Work authorising a person to perform one or more classes of high risk work. ca hih i w
formwork design. fw a
Astructuralassembly,anumberofwhichareusedtosupporta formworkdeck.Bearersareplaceddirectlyontheseframes.
AclassofworklistedintheSchedule–LicenceClasses and Denitions,oftheNational Standard or Licensing Persons Perorming High Risk Work.
Anyhorizontalmemberofaformworkorscaffoldfra methatis
cptt p
aworkingplatform(includestheterm‘transom’inreferenceto scaffolding).
In relation to performing an inspection or other task for a control
measure–isapersonwhohasacquired,throughtraining, qualicationsorexperience,theknowledgeandskillstodothework inasafeway,including: (i) soundknowledgeofrelevantAustralianStandards,codes of practice and other legislation; and
(ii)soundknowledgeof,andcompetencein,therisk managementprocessforerecting,alteringand dismantlingformwork,including– •hazardidenticationandriskassessment •measurestocontrolexposuretorisks •safeworkpracticesandprocedures,and •howtoplanandprepareformwork.
Hizta provided as stiffening for the frame and may also be used to support
Itdiat pat
Aplatformatleasttwoplankswide,locatedlessthan2mabove a continuous deck. jit
Asecondaryhorizontalsupportmemberfortheformworkdecktha t isplacedontopof,andatrightanglesto,thebearers.Joistsare usually constructed from timber but are sometimes constructed from
metal,suchasinthecaseofsomemodularformworksystems. mta d
Aformdeck,madeofsteelsheetsthatarenormallynotreco vered. mda w
ctait hti
Aformworksystemthatisspecicallydes ignedandconsists
Aprotectivestructurexedtotheperimeterofthebuilding,structure
of components that are not intended to be used with other systems.
or working platform to contain objects and prevent them from falling.
Pit d
ed ptti
Edgeprotectionthatisprovidedontheperimeteroftheprotection
Abarriererectedalongtheedgeof– • abuildingorotherstructure • anopeninginasurfaceofabuildingorotherstructure,or • araisedplatform
formwork to be erected.
(Note:Perimeteredgeprotectionwillpreventafallfromtheoutside perimeter of the formwork but will not prevent internal falls through
theformwork).
to prevent a person falling.
29
Propping
Slender structural members placed in a vertical position between two horizontal suraces and used to support the upper surace. The proprietary term ‘acrow’ is oten used to describe a prop. The height o propping is usually adjustable. Vertical member
A vertical structural member which may or may not orm part o a rame, also known as a standard, prop or vertical tube.
Appendix 2: Training Under the South Australian Occupational Health, Safety and Welfare Act 1986, Part 3, Section 19 – Duties of employers …“an employer must provide such information, instruction, training and supervision as are reasonably necessary to ensure that each employee is safe from injury and risks to health”... Anyone involved in erecting and dismantling ormwork must be trained to perorm their work in a manner that is sae and without risks to health or saety, and must have evidence o their training. The employer must monitor their systems o work and, when necessary, provide reresher training to ensure that sae practices are being ollowed. The requirement or an employer to ensure that training is provided has been identifed in several sections o this guide. Some o this training relates to specifc competencies required under the legislation and must be conducted by a registered training organisation. For example: • scaffolder • rigger • dogman • craneoperation.
Other duty o care training may be provided and delivered by manuacturers or suppliers o equipment and materials or, where resources are available, developed and delivered in-house by competent trainers. This includes training or: • formworkconstructionsystems • modularworksystems • workingatheightharnesssystems.
Sae work method statements, developed by experienced workers and their supervisors, can orm an excellent basis or introductory training or inexperienced or new workers in the ollowing areas: • erectingofalltypesofformwork • dismantlingofalltypesofformwork • layingofmetaldeck • slipformsandjumpforms.
Each site manager must assess training requirements and ensure that everyone on-site can competently and saely undertake their work without adversely aecting the health and saety o others.
30
Appendix3:Sampleengineer’scerticationletters Refertosection2.2.2Formworkdesigncerticationrequirements.
(A)Engineer’sCerticationLetter– n aiati t di …………………………………. …………………………………. …………………………………. …………………………………. Dear ……………………
Project…………………………………… I certify that the formwork system detailed below has been designed in accordance with AS 3610 – Formwork or Concrete and
AS 3600 – Concrete Structures ,andtheprojectdocumentationincludingthestructuralengineeringdrawingsandspecications. The system is detailed on the drawings and documentation listed below.
Dawi
Dawi a
Specications
Yoursfaithfully
SIGNATURE Engineer’sname
DocumentControlSystemNo.
31
(B)Engineer’sCerticationLetter–vaiati t di
…………………………………… …………………………………… …………………………………… ……………………………………
Dear ……………………
Project……………………………. I certify that the variations to the formwork system detailed below have been checked and satisfy the AS 3610 – Formwork or Concrete,
AS 3600 – Concrete Structure andtheprojectdocumentationincludingthestructuralengineeringdrawingsandspecication.
vaiati
Yoursfaithfully
SIGNATURE Engineer’sname
DocumentControlSystemNo.
32
Dtai aiati w t
Pt dawi
Appdix 4: ctti hit (Note: ‘#’ denotes an item that, i not passed by the competent person, must be reerred to the engineer. All other items not passed by the competent person must be corrected on-site and certifed by the competent person when he/she is satisfed.) lad
• Stackedloadlimitsareidentiedforallstages? • Stackedmaterialsareonspreaders? # Willanyconstructionproceduresexceedthestackedloadlimit? matia
# Correctformmaterialsarebeingused? • Formfaceconditionissuitableforthenishrequired? fw a
# Aretheformworkframesinthecorrectlocationand correctnumber? • Aretheytodimensionandwithintolerance? • Aretheyaccuratetoline,levelandplumb? bai/Pp
# Aretheredifferentpropsorbracestotheonesindicatedon theformworkdrawings? • Arethepropsplumb? • Arepropsstraight? • Arebaseplatesonadequatefoundations? • Areallloadscentrallyplaced? • Ifno,arealleccentricloadscertied? • Aresupportedelementswedgedandnailed? • Isthebracingcorrectandrmlyconnected?
Wattiht
• Areallformpaneljointsproperlysealedandcramped? • Aretheconstructionjointssealed? ct/cti
• Whatisthemaximumrateofplacementpermitted? • Aretheformsmaintainingline,level,plumb,shape,etc duringconcreting? stippi
• Whataretheminimumstrippingtimes? • Hastheprojectdesignerpermittedmodicationofthese? • Dotheproceduresenablestrippingwithoutdamagetoform or concrete? • Aretheprovisionsconsistentwiththere-usetimesrequired? • Doesthecranehavethenecessaryslingsetctomovethe formsquickly? • Whatcuringmethodsaretobeusedoncetheformwork is removed? • Isthestorageareafortheformworkorganised? sat
• Arethereadequateguardrails,handrails,walkways,signs,etc in position?
fixi
• # # • • #
Isthenailing/screwingadequate? Arethetiesthecorrecttype? Aretheyonthecorrectgrid? Areallties,clampsandboltstight? Arewedgestightandnailed? Areanyconnectionsbetweentraditionalformworkandmodular formworkcorrect?
ba-pppi
# Istheback-proppingsystemcorrect? # Arethenumberofoorsrequiredforback-proppingcorrect? # Hastheproppingbeencorrectlyreleasedandtightened,as specied,priortotheconcretebeingpouredabove? cai
• • • • •
Aretheformfacescleaned? Isanydamagecorrectlyrepaired? Isthecorrectreleaseagentinuse? Isitbeingcorrectlyapplied? Hasalldebrisbeenremovedfromwithintheform?
33
Appendix5:Samplestructural(pre-pour)certicate Refertosection2.2.5On-sitecoordinationandverication
Engineer’s/Competentperson’sname:……………………………………………….…….Telephone:…………………………….. Address:………………………………………………………………………………………………………………………… Fax:………………………………………………. Mobile: ……………………………………………
Date: ……………………………..
Project:………………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………………………
Level:……………………………….
Area:……………………….
Thisistocertifythatthe………………………..Formworkfortheaboveprojecthasbeeninspectedandisconsideredtobeadequateto supportthedesignloadsinaccordancewiththerelevantAustralianStandardsincluding AS 3610 Formwork o Concrete. The following items were included in the inspection:
It
cditi (i)
W qid (i)
Base plates
PASS
FAIL
No
Yes
Frame spacing
PASS
FAIL
No
Yes
Frame bracing
PASS
FAIL
No
Yes
Frame extensions
PASS
FAIL
No
Yes
Bearer size and spacing
PASS
FAIL
No
Yes
Joist size and spacing
PASS
FAIL
No
Yes
Prop spacing
PASS
FAIL
No
Yes
Prop bracing
PASS
FAIL
No
Yes
Eccentric loading
PASS
FAIL
No
Yes
Prop inclination
PASS
FAIL
No
Yes
Timber condition
PASS
FAIL
No
Yes
Steel condition
PASS
FAIL
No
Yes
Nails in plates as required
PASS
FAIL
No
Yes
Column framing
PASS
FAIL
No
Yes
Column bracing
PASS
FAIL
No
Yes
Plywood xing
PASS
FAIL
No
Yes
Dtai dia w qid
…………………………………….
…………………………………
Engineer’s/Competent person’s name
Signature
34
Appdix 6: Dt d i w t s pat
(a) Notlevelledinoreccentricallyplaced (b) Inadequateload-carryingcapacityoftheground, or uneven bedding
(c) Deteriorationwithtime,e.g.duetoweatherconditions (d) Deteriorationofload-carryingcapacityofthe ground, e.g. washouts
(e) Crushingduetoinadequateloaddistributionfromvertical andhorizontalmembers. Hizta ppt
(a) Foldingwedges,tapercuttotoocoarse,notproperlycleatedor cut from wet material
(b) Inadequatelateralandtorsionbracing,e.g.betweentelescopic centres,centrescarryingheavyloadsoverlongspans,steel propssupportingheavyloadsat,ornear,maximumextension
ga
(a) Excessivetolerancesinconstruction (b) Failuretochecktightnessofbolts,wedges,etc (c) Failuretocontrolverticalrateofplacementof concrete (d) Failuretocontrolplacementofconcrete,causinguneven loading of forms
(e) Inadequateallowanceforupliftofconcreteunderinclinedforms (f) Inadequateallowancefortheeffectsofvibrationonjoints (g) Inadequateallowanceforstressesinducedbypre-stres sing, temperature and moisture movements
(h) Noallowanceforwindloading (i) Noallowancefortheeffectofvibrationonties,struts,braces, and wedges
(j) Unrealisticassessmentofstressesduetoover-simplicationof design assumptions
(k) Unequalloaddistributionbetweentwoormorememberscarrying a common load
(l) Penetrationstometaldeckstobesupported.
and between towers supporting independent spans
(c) HorizontalmembersnotcentrallyplacedinU-heads (d) Inadequatesupportstocantilevers,e.g.strutssupportingdeep beam sides on the outer face of the structure
(e) Inadequatebearingareastoverticalsupportsandundersideof principal members causing crushing
(f) Inadequatesupporttopreventoverturningofdeepprincipal membersbecausestirrupsorU-headsomitted (g) Boltedtimberconnectionsnotstaggeredcreatingtendency to split out. vtia ppt
(a) Inadequatebracingduringerection (b) Supportsnotplumb (c) Inadequatelateraltiesand/orverticalandplanbracing (d) Notiesbetweenstandardsatpointofloading(mostimportant wheretelescopiccentresarebeingsupported) (e) Incorrectprovisionofpropsfromoortooor (f) Lackofrigidityofscrewconnectionsduetoover-extensionor lack of bracing
(g) Incorrectpinsusedinadjustablesteelprops,e.g.nails,mildsteel bolts and reinforcing bars used
(h) ScaffoldU-headsorsupportsomittedorotherwis eeccentrically loaded without allowance having been made for this condition
(i) Bearingplatesdistorted(topandbottomplatesofsteelprops) (j) Inadequateordiscontinuousbracingtoscaffold (k) Basejacksover-extended.
35
