18. EXTERNAL WORK
CONTENTS PAGE NO.
1.0DEFINITIONS ...... 3
2.0SCOPE OF WORKS ...... 3
3.0EARTHWORKS ...... 3
3.1SoilPreparation
3.1.1Compost
3.1.2Fertilizersand Additives
3.1.3Final FinishingOff
3.1.4SurfaceDrainage
4.0IRRIGATION ...... 4
5.0PLANTING...... 11
5.1OpenGroundplants
6.0WATERING...... 11
7.0PERIODOFMAINTENANCE ...... 11
8.0DRAWINGS ...... 12
1.0DEFINITIONS
1.1For thiscontract thefollowingshall apply:
1.a.1 “Site”shallmeanthelocationwheretheworksaretobeexecutedorcarriedoutas provided bythe client forthepurposeofthiscontract.
1.a.2“Client”shall meanStellenbosch University
1.a.3“Landscape Architect”
1.a.4 “LandscapeContractor”shallmeanthepersonorpersons,firmorcompany,whose quotationforthe landscape worksas defined in the contract,hasbeenaccepted byor on behalfof the Client.
1.a.5“TheWorks”means assetoutin item2.0
2.0SCOPE OF WORKS
a)Earthworks–bed preparation, finegrading and mulchingofbedsafterplanting.
b)Design,supplyand installation ofafullyautomatic irrigationsystem.
c)Construction ofpavingetcas perBill of quantitiesand construction specifications.
d)Installation ofplantsasperPlant Plan,Plant Listand Bill of Quantities.
e)Maintenance ofworksforaperiod of three(3) monthsto Final Approval.
3.0EARTHWORKS
a)SOILPREPARATION
3.a.1Compost
a) Onlymediumgrade(standard)composttobeused. Theinvoiceforthecompost mustbesubmittedwiththecontractor’spaymentclaiminorder for thisitemtobe processed.
b) Compostmustbedugtoaminimumdepthof350mmforbedareasand50mm for lawn areas.
3.a.2Fertilizersand Additives
a)TheLandscapeContractormustallowforfertilizerspertree,shrubandground coversasperBillofQuantities.Invoicesforthefertilizerstobesubmittedwith thepaymentclaiminorderforthisitemtobeprocessed.Delivery notesarenot acceptable.
3.a.3Final FinishingOff
a)Landscape Contractor to ensure that topsoil in all bed areas is clean and Contractorshallallow forremovingofallstoneslargerthan200 mmØandalien materials,perennialweeds,roots andotherplanmatter,brokenbricksand concrete.
b)Finegradingofthetop150mmistobecarriedouttoensureatrueand specifiedlevelandslopetoavoiddishingorotherdepressionswherewatermay
collect.Theuseofaheavyrollertorollouthumpsinbedareaswillnotbe permittedandanyotherareathatbecomesundulycompactedduringlandscape
operation shall be loosened by forking and harrowing by the Landscape
Contractor.
c)Thefinallevelofbed/lawnareastobelevelwithallkerb/pavedareastoallowfor shrinkage and/orsettlementorinrelationto surroundinglevels.
3.a.4Surfacedrainage
TheContractorwillensurethatallareasdrainevenlyacrossthesiteandthatthesurface run-offwill flowintoageneral surfacedrainage pattern.
4.0 IRRIGATION
Thisisa design andsupplycontract.The irrigation contractorshall be aFULL MEMBER ofthe LIA andcheckswillbedoneby theLandscapeArchitect toensure this. AssociatemembersoftheLIAdo notqualifytotender.
The irrigation contractor shall liaise with the Facilities Management Department priortodesign works withregardtotheexistingsystem,flowrequirementsandwaterconnectionpoints etc.
a)Uponsubmittingthetender,anannexurewithapricedlistofmaterialsmustbesubmittedfor adjudication purposes.
b) Alldesigns must bebasedontheHunterproductandallcomponentsmustbeSABS
approved.
c) An allowance of3 months maintenancemustbeincluded intothe schedule of quantities.
d)Anas-builtdrawingmustbesubmitteduponPracticalCompletionalongwithallguarantees and manuals.
Materials
7.7.1 Piping
1)General
Nosubstitutionofsmallerpipesofalowerpressureratingshallbeaccepted,butthe substitutionoflargerpipes,orpipesofahigher-pressureratingmaybeaccepted(at
theratestenderedforthespecifieditem)atthesolediscretionoftheLandscape
Architect. All piping shall be installed asperthemanufacturersrecommendations.
AllpipingshallmeettherepresentativeSABSSpecificationsandshallbeartheSABS
mark.
All HDPE piping will be manufactured using High Density Polythylene, having a densityofnotlessthan0,949gramsforcubiccentimeter. ThepipewillbeTypeIV
Class6whichmeetstherequirementsofSABSSpecificationNo. 533Revisedand shall bearthe SABSmark.
2)HDPE Pipe Fittings
HDPEpipefittingswillbethecompressiontype,comprisingoftwobasicparts,the body intowhichthepipeisinserted andsealson an“O”Ringanda compressionnut whichscrewsontothe body andtightens the grip onthe outsideofthepipe. Fittings usedonHDPE pipeswillconform to thedimensionsaslaiddownin theSABS Specification No.533 Revised.
Saddleswillbefittedwitharubber“O”Ringseatsetinarecessunderthesaddle outlettoeffectawatertightseal. TheoutletwillhaveafemaleBSPthreadsizedto suitthe fittingstobe attached. Saddledimensionswillconform to HDPEpipe specificationsSABS533Revised. Saddlesfor63mmHDPEpipeshallhave4bolts andfor50and 40mm shall have 2bolts. All nutsand boltsshall be stainless steel.
7.7.2Pop-up sprinklersandsprayers
3)General
Unlessotherwisedirected,pop-up sprinklers/sprayersshallbeinstalledperpendicular tothe finishedgrade. Sprinklers/Sprayersshallbeleftprotrudingabovegroundlevel untilthe grasshasbeen planted,afterwhichthecontractorshallbe requiredto make finaladjustmentsto height,as wellassettingthearc tobeirrigatedandradius of trajectory.
Spray nozzlesinthegroundcoverareasshallbe300 mmabovefinishedgrade,with the soil aroundtheriserpipe tampeddown to hold theriser in vertical position. Setting ofthespray nozzlearcand radiusoftrajectory shallbesetafterplanting,asperthe drawingorasdirectedby theLandscapeArchitect. Sprayersover300mmtallare to be supported with metalstakesand securedas perspecification.
Itshallbetheexclusiveresponsibility ofthecontractor tocorrectly nozzlesprinklersand sprayersinaccordance withtheareasto beirrigatedand thespecifications. Nuzzlingwillbe suchinaccordancewiththearea to beirrigatedandthespecifications. Nuzzlingwillbesuch that theentireareaofa station will receive aneven application ofwater.
4)Pop-up Sprinklers
Thesprinklersshallbeofthe geardrivenrotary type. Thesprinklershallhavean exposedsurfacediameterafterinstallationof50mmandshallhavea20mmBSP female inlet.
Thebody ofthesprinklershallbeconstructedofnon-corrosive,heavy duty ABS.The sprinklershall carryatwo yearoverthecounterexchange warranty(not prorated).
5)Pop-up Sprayers
Eachpop-upbodyshallhaveacapturedfilter screenandawipersealshellthat providesapositivesealwithnoflow by. Allmodelsshallhavetheabilitytoadjustthe directionofthespray nozzleviaamechanical ratchetmechanism. Spray headsshall be constructed ofhigh-grade,non-corrosive plastic and stainless steel parts.
6) Sprayersand standpipes
Riserpipesshallbe½”galvanisedironorPVCpolyvinylchloridewith½”BSPmale
threadon eachend.The riserpipesmustbeapproved bythe Landscape Architect.
7.1.3Automaticcontrol
Irrigation control shall be automatic. If automatic, thecontrollersshall be eitherA/C powered froma mainsconnectionofMasterswitch foron/offandautomaticsettings.Reset circuitbreaker.
Rapid advance through station,which is setto zero oroff: Independentstation timefromsix tosixty minutesperstation. Dualprogrammefacilitywitheachprogrammeofferinga minimumoftwostartstimesperday. Thecapabilityofoperatingatleasttwo24volt solenoidvalvesandapumpstartrelay simultaneously. Aweatherprooflockablebox suitablefor mounting outdoors.
7.1.4Electricsolenoid valve
The valve shall be sizedto suit therequired demand.
Thevalvesshallhavethecapability ofbeingmanually setandadjusted priortoelectrical connectionandmay bemountedinany position. Thevalvebodyshallhave aglobeoran angleconfigurationoptionandbeconstructedofhighdensity,highstrengthCPVCand PVCmaterial. Thediaphragmassembly shallbeconstructedofstainless steel,plasticand highstrengthfabricreinforcedsyntheticrubber. Thevalvesolenoidshallbe24VoltA.C. and betotallyencapsulated byglassfilled polypropylene.
Solenoid Valve Features.
Adaptableglobe or angleconfiguration. Flowcontrol(standard).
Manual bleed.
High efficiencytotallyencapsulatedsolenoid.
Inrush voltampsat24 VAC11,50VA Inrushcurrent at 24 VAC,48 amp
Holdingvoltampsat 24 VAC 5,75VA
Holdingcurrent at 24 VAC ,24amp
7.1.5Dripperringsaroundtrees
Each tree asrequired inthe Plant List and specifications shall have adripperring installed around itsbase.Thisdripperring shall consist of a 1.2lengthofPressureCompensated Integral Dripper-line,with drippersspaced at300mm intervals, and curved intoacircle aroundthe baseof thetree.The dripperring (unless otherwise specified) shall be installed on thesurfaceofthesoil,under themulch layer,such that thetrunkof thetree isinthe centerofthering.Thering shall be held inposition bymeansof3galvinisedwire pegs,
200 mmlong,installed at equal intervals throughout thering. Careshall be takenin installingthese pegs, soas not todamagethe dripperlinesin anywayorimpedetheflow
ofwaterout ofthedrippers.Thedripper ring shall be connectedtothedripperlateral line
installed 450 mm belowthegroundsurface.
Treesrequiring different waterrequirementsshall not be connectedtogetheronthesame irrigation station. Similarly,treesplanted intreerings inside paved (andcompacted)areas shall notbeconnectedtogether onthe sameirrigation station with treesinopen landscape areas. Shouldthe projectspecificationscallfor treesin landscape areasalreadyirrigated byconventional means, to beprovided with supplementarydripper ringirrigation, these treesshall also notbetogether onthe sameirrigation station astreesnot irrigated in this way.
7.1.6Accessories
7)Valve boxes
Valveboxesshallbeinstalledovereachandevery valve,isolationvalve,scourvalve, pressureregulatingvalveandairreliefvalve. They shallbelockableandsizedto ensureeasyaccesstothe valve encase.
8)Rain-sensor
A separaterain-sensor shall be installed on eachirrigation controller, orgroup of controllerswith aseparate commoncable.Therain-sensorshall actasaswitch to break the circuit tothe solenoid valves oftheirrigation systemwhen ithasrained, allowingthe irrigationcontrollerto advance asscheduled withoutopeningthe solenoid valves. The rain-sensor shall be adjustableto allowthe interruption ofa scheduled irrigation cycle once apre-determined amountof rain hasfallen.The rain-sensorshall automaticallyreset the irrigation circuit when rainfall hasceased andsufficient evaporation hastaken place,allowingthenextirrigation cycle totakeplace.
Therain sensorshall beofthe enclosedcaptype(theopen panrain-switch,which is noteffective in highwindconditions, shall NOT be permitted)andshall allowfor manual overriding oftherain-switchfunction.
The rain-sensorshall be mounted ina surface where itwill be exposed tounobstructed rainfall,butshall notbeexposed tothe sprayofthe irrigationsystem.
It shall be connectedtothe rain-sensorport of the irrigationcontroller(ifsuch a port is available)orconnectedthroughthe common cable exiting the controller.Should a
pump/sbe presentintheinstallation,which theirrigationcontrollerdirectlycontrols, the rain-sensor shall comply with local municipal regulationsand shall bein
accordancewith themanufacturer’sspecifications.Therain-sensor shall be one of the
following(orsimilarapproved byLandscape Architect):
Nelson 8501 Rain-Trip rain-sensor
HunterMini-Clickrain-sensor.
7.2Installationandtrenching
7.2.1Trench excavation
TheContractorshallperformalltrenchexcavationstoadepththatwillensurenolessthan
400mmofcover,fromfinishedgrade,overpipesand/orelectricalcables. Allexcavated materialnotrequiredforfillorbackfillshallberemovedandwastedasdirectedbythe
SU Facilities Management Department or LandscapeArchitect. Trenchesshallbeexcavatedtruetoline,sothataspacenotless
than 100 mmisprovided oneachside of the pipe.
7.2.2Pipe Assembly
Theinteriorofthepipeshallbethoroughlycleanedofallforeignmatterbeforebeing loweredintothetrench,andshallnotbelaidinwater,watershallbe keptoutofthetrench untilthejointingandpartialbackfillingiscomplete. Whenworkisnotinprogress,open endsofpipesand fittingsshallbesecurely closedsothatnoforeignmaterialwillenterthe pipes. Anypipe thathasthegradeorjointdisturbedafterlayingshall betakenupand re- laid.
Fittings,bendsinthepipelinesandendsoflinesshallbefirmlywedgedagainst thevertical undisturbedfaceofthetrenchbymeansofconcretethrustblocks. Sizeofthrustblocks shallbeasperthemanufacturer’srecommendationsfor thesoil typeinwhichthepipeis installed.
PVCpipe,couplingsand fittings shallbehandledandinstalledinaccordancewiththe manufacturer’srecommendations. Eachpipe length shallbeproperlyjointed toallow expansion and contraction.
Allpipeinstalledunderhardsurfaced roadsorproposedroadsshallbesleevedinClass16
PVC. Thesesleevesshallbeofamplesizetoaccepttherequiredmaterialstopass throughthem.
7.2.3Pop-up Sprinklers
Sprinklerheadsinstalledinareaswheregrasshasnotbeenestablishedshallbeinstalled ataminimumof80mmabovegrade. Loweringofsprinklerheadstogradeshallbedone bythecontractoraftertheturfhasbeenestablished. Noheadsshallbeinstalleduntilthe Landscape Architectapproves the positionsand spacing.
7.2.4Automaticcontroller
A controllershall be installed asperthe manufacturer’s recommendations,on pedestal mounts tobesetinconcrete. Thecontrollers shall beinstalledin thefieldasperthe irrigationlayoutplanandwithpriorapprovaloftheLandscapeArchitect. Surge protection shall be installed ontheprimaryside ofeach controllerandtoeachfield wire terminal.
7.2.5Electrical wiring
Allelectricalwiringshallbeinstalledaccordingtolocalmunicipalregulations. Allwiring shall be bound with tape every 6 (six) metres and shall be a minimum of 50 (fifty) millimetersbelowthe top ofthe pipe. Careshall be used to leave plentyofslackin the pipe when installingin thetrench.
AllwireinstalledunderhardsurfacedroadsorproposedroadsshallbesleevedinClass16
PVC. Thesesleevesshallbeofamplesizetoaccepttherequiredmaterialstopass
throughthem.Wirerunswill be accuratelymarked onthefinal“As-Built”drawings.
7.2.6Backfilling/pipelineflushing andtesting
The trenchesshallbe carefullybackfilledwiththeexcavatedmaterialsapproved for backfilling,consistingofearth. Loam,sandyclayandsand,orotherapprovedmaterials, freefromlargeclodsofearthorstone. Backfillingshallbedonein200mmlayersand properlytamped,so as to preventsubsidence.
Any trenchesimproperly backfilled,orwheresettlementoccurs,shallbereopened to the depthrequired forcompaction,thenrefilledandcompactedwiththesurfacerestoredtothe requiredgrade andcompaction,andleftin a level surface condition.
7.3Finalization
7.3.1Excavation and backfill
9)Theirrigationsub-contractorshalldoallnecessarytrenchingandbackfillingrequired fortheproperinstallation ofthesystems.
10) TheIrrigationsub-contractorshallusebackfillingequipmentthatwilltampthebackfill in suchamanner that nosetting will result.
11) Backfillmaterialwillbefreefromrock,largestonesorotherunsuitablesubstancesto preventdamageduring backfill operations.
12) Backfillingoftrenchescontainingplasticandcopperpipeshallbedonewhenthepipe iscool toavoid excessive contractionin cold weather.
13) Minimumdepthofcoveroverpipe50mmindiameterandsmalleristobe400mm deep,63 mmand largeris tobe 500mm.
14) Excavationswillbeinsoftandpickablematerial,whereundergroundstructuresare encountered thedesignoftheirrigationlayoutwillbeamendedtoavoidsuch structures.
15) Wheretrenchingoccursbehindkerbs/edgings,backfillmaterialmustbecompactedto
90 %MOD AASHTODensity.
7.3.2Material Storage
Materialsshallbestoredinsucha manner to ensure thepreservationoftheirquality. Suitablelocation forstorageofmaterialsmustbearrangedwiththe MainContractor. Securityofstoragematerialsis theresponsibilityoftheIrrigation sub-contractor.
7.3.3Utilities
All damage to utilities and existing water lines will be repaired by the Irrigation sub-contractorathisexpenseprovidedthelocationhasbeenindicatedby theMainContractor when requested bythe Irrigation sub-contractor.
7.4Completion
7.4.1Testing
16) DuringthecourseofinstallationwheretheIrrigationsub-contractorhasatleast50% ofmainlinevalvesinstalled,heshallcall forapreliminaryinspectionby theLandscape ArchitectorOwner’srepresentative. The Irrigationsub-contractoris toleavea minimumof30%of theinstallation exposedforvisual inspection.
17) Theentiresystemwillbetestedatthenormalworkingpressureofthesystem. Upon visual inspection of the ground, should any leak be found, it shall be promptly repaired.
18) Testing shall be performed afterthebackfilling and compaction operation.
19) Thesystem isto bepressuretestedbefore trenches arebackfilled.
7.4.2Adjusting thesystem
Uponthecompletionofthesystem,theIrrigationsub-contractorshalladjustthesprinkler heads toprovide optimumperformance.
7.4.3As-builtdrawings
20) Aftercompletionofinstallation,theIrrigationsub-contractorshallfurnishtheClient’s representativeorLandscapeArchitectwithreproducible“as-built”drawingsshowing allelementsofthesystemandpipelinestoreasonablescaleandprovideaminimum oftwo dimensions takenfrom fixed, obviousobjectsto each control valve.
21) Instructionsheetsandpartslistscoveringalloperatingequipmentwillbeboundintoa folderand furnished to the Owner’s representative orLandscape Architectin two(2) copies.
7.4.4Instructions
Aftercompletion,testingandacceptanceofthesystemtheIrrigationsub-contractorwill instruct the Client’spersonnel in theoperation and maintenance of the system.
7.5Warranty
7.5.1Guarantee
22) Foraperiodofone(1)yearfromdateofcompletionoftheinstallation,theIrrigation sub-contractorshallpromptly furnishandinstall,withoutcosttotheOwner,anyparts that prove defective in material and/orworkmanship.
23) Anydamagetotheequipmentnotcoveredbytheguaranteewillberepairedbythe Irrigationsub-contractorandcharged tothe Ownerat the Irrigationsub-contractor’s regularservice rates.
24) ItwillbetheresponsibilityoftheIrrigationsub-contractortogetasignedworkorder beforemaking anynon-warrantyrepairs.
5.0PLANTING
PLANT GUARANTEE
Allplantmaterialshallbe guaranteed for thedurationofthecontractperiodupanduntilthe issueofaFinalApprovalCertificate.Deadordyingplantswillbereplacedimmediately
duringthecontractperiodatthe contractor’sexpense.Attheendofthecontractperiodall deadordyingplantsaretobereplacedatthecontractor’sexpense.Theplantguaranteewill
coverallplantsspecifiedbytheLandscapeArchitect.IftheLandscape Contractorhasany objectiontoanyoftheplantsspecified,heistostatehisconcernsbyletterofqualification
whensubmittinghistender;ifnoletterorqualificationissubmitted,itwillbeacceptedthat theLandscapeContractorhasnoobjections totheplantmaterialspecifiedandnoplantswill be exempt from theguarantee.
SCOPE OFWORKS
Underthissection,workwillconsistofthefollowingandshallbeperformedbyaspecialist and approved selectedcontractor.
Furnishalllabour,materials,transportationandservicestoinstalland maintainplantmaterial inaccordancewithdrawingsandspecificationsasapplicabletothevariousvegetation types. Contractortosourcehardened plantsfromsuitable sourcesfor the hostileclimateof the site.
Stateinwhichstatesitewillbehandedto theLandscapeContractore.g. cleanofallbuilders rubble and debris, planting tobe donein accordance with GeneralSpecifications.
6.0WATERING
TheLandscapeContractorshallbe responsible forthe wateringand maintenanceofallplant materialbeforeandafterplanting.Anylossesduetolackofwateror neglectwillbethe responsibilityoftheLandscapeContractor. Waterwillbesuppliedatnoextracosttothe Landscape Contractorfor the purpose ofwatering theplants.
7.0PERIODOFMAINTENANCE
TheFinalApprovalCertificatewillbeissuedafteraperiodof three monthsifitis so justified. Maintenancemay commenceonlyafterwrittenconsenthasbeen receivedfrom the Landscape Architect. The Contractorwill guarantee all plantmaterial oncehe hassigned and accepted thedocument.Any lossesofplantswillbe for theContractor’s accountuntilaFinal Completion Certificatehas been issued.
8. CONSTRUCTION
8.1Demolition Works
Siteistoberemoved ofall material orstructuresthat aretobereplaced or upgraded. WhererequestedintheBillofQuantities oronthe drawings materialsthataretobestoredforlateruseby theUniversity,aretobe carefullyremovedandstackedor stockpiled as directedonsite.
Allmaterials thatcannotbere-usedare to beremovedfromsitetospoil.
8.2BrickPaving
8.2.1 Bed Preparation ofIn-situ sub-grade
Oncelevels have beenestablishedonsiteofthefinal surfaceshowing thenew grades,thein-situsubgradeistobepreparedasperthe detailsattached. Theselectedsubgradeistobecompactedto93% ofthemodifiedAASHTO density.
Itis possiblethattheexistingsubgrade andsub-basematerial could be reusedin-situandreuseofthesematerialsistobeestablishedwith theEngineerprior to anyremoval or stockpiling.
8.2.2 Sub-base
Thesub-basematerialistobereusedin-situornew sub-base constructedin accordancewiththedetailsattached. Allsub-baseis to becompactedto95%ofthemodifiedAASHTO density.
Sub-baseinthegeneralpavedareasistobeaminimumthicknessof
125mmand in theparkingareas,150mm.
8.2.3 Paving
All pavingis tobea minimum45MPa,tothetype,colourand dimensionsas shown onthedrawings or in the Bill ofQuantities.
8.2.4 Headers /Edging
All headersand edgingtobelaid on 20MPa,concretebedding as shown onthedetails attached.
Type,colouranddimensionstobeasshownonthedrawingsorinthe
Bill ofQuantities
8.2.5 Street Furniture
Allstreetfurnitureistobesuppliedandinstalledtodetailsasshown onthedrawings.
8.2.6 SeatingWall
Seating Wallsaretobeconstructedcompleteinaccordancewith drawings and details attached.
8.2.7 Irrigation Ducts
Irrigationducts/sleevesaretobe110mmdiauPVCClass51toSABS
791andlaidinpositionanddetailas shownon the drawings.