Heinke Tunnel Segment Gaskets

8/12/2019 Heinke Tunnel Segment Gaskets

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einke Tunnel Segment askets

\tTRELLEBORGNGIN R SYST MS


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H INK TUNN L S GM NT G SK TS

Trelleborg Bakker has unrivalled expertise inseal design and elastomer technology, and isthe world's leading manufacturer ofelastomeric gaskets for immersed tunnels,cUt cover tunnels and bored tunnels. Forthe segmental lining of bored tunnelsTrelleborg Bakker supplies tunnel segmentgaskets (TSGs) under the trade nameHeinke. Heinke TSGs, which are located inprecast grooves encircling the mating facesof each segment, give a secure rubber-to-rubber waterproof seal as soon as thesegments are bolted together. The lowcompression set and stress relaxation values

of the elastomeric compound used in theirmanufacture enable elastomeric TSGs torecover under reduced applied load therebymaintaining a positive seal betweensegments despite ground movements.Trelleborg Bakker manufactures a range ofHeinke TSGs designed for precast concrete,steel and cast iron segments used in thelining of tunnels or shafts and large mainssewers. All are precision engineered to meetthe precise requirements of individualprojects.

TOT L QU LITYTrelleborg Bakker operatesa Quality System which isISO900 1 and ISO 14000approved.

ISO9001 ,ISO 14001 SCC

mIIIREGISTERED


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ENEFITS OF EL STOMERIC T s

Elastomeric TSGsI provide an economicand effective solutionfor sealing tunnels andshafts against wateringress. Compared toother sealing methods,elastomeric TSGs offermany benefits.

Heinke Tunnel Segment Gaskets:. are easyto install;. createan effectivesealwhen bolts aretightened, immediately creating dryomts;. assureaneffectivesealdespitegroundmovement and alternating wet and dryconditions;. havea provenreliability,eliminatingtheneed for costly remedial work to seal leaksafter construction;. and havea provenrecordofdurability,being resistant to chemical attack andmicrobiological degradation.

nuf cturing c p bilityTrel~eborg Bakker - a company with ane~tabdsh~d history of a long-termcommitment to serving the constructionindustry - is a market leader in thedevelopment of seals and gaskets.

Using experience gained over 125 years,Trelleborg Bakker is able to develop andcompound materials to meet the mostexacting requirements. Its Heinke TSGs,with their complex cross-section of ribsand holes providing strength andcompressibility, are manufactured by anextrusion process which incorporates themost up-to-date equipment for thecontinuous monitoring of sectionaldimensions to ensure that every TSG is heldwithin specified tolerances.The extruded Heinke TSGs are cut torequired lengths and shot-moulded for jointintegrity to form a one-piece, four-sidedgasket that fits perfectly into the specifiedgroove of the segment.


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TE HNI L

When specifying TSGs for segmentedtunnel applications, there are a number offactors which need to be taken into account.It is the particular combination of factors ineach case which determines the eventualchoice of gasket, which in turn ensures anefficient, watertight seal over the projectedservice life of the tUnnel.Upon request we can forward a SpecificationGuide which lists these factors. On the basisof information provided, Trelleborg Bakkerwill be able to specify the most suitable andeconomical Heinke TSG for a particularapplication. To ease the selection process,customers are invited to consult TrelleborgBakker who will identify, test anddemonstrate the appropriate gasket for aparticular project.orking and test pressuresSegmental linings require gaskets to ensurea watertight seal. Ground water is normallyunder pressure and the chosen gasket musttherefore be tested

for its ability towithstand thepressures involved.

FigA

T-Configurationst rig

This can be done byusing one ofTrelleborg Bakker'sspecially designedtest rings, asillustrated in Fig A.These are built to

simulate the worst conditions which can beexpected during construction and servicelife of the tunnel. Hydrostatic pressure isbuilt up within the rig to-the required testpressure and maintained for a prolongedperiod of time, generally 72 hours.The test pressure is always higher than thehighest working pressure to ensure a marginof safety.

T

aps and displacementsGaps and displacements occur betweensegments, either as an allowance forbuilding tolerances or to help steerage,line and level during the construction of thetUnnel (see Fig B).

FigBDisplacement

Gap

... Cross section through segment to show typicalgap and displacement

The purpose of the TSG is to seal to therequired pressure at the maximum expectedgap and displacement. As the size of the gapand/or displacement increases, the abilityfor a given TSG to withstand waterpressure decreases, as illustrated in Fig C.There is therefore a maximum pressure atwhich any TSG will seal for a givenmaximum gap and displacement. Thechosen gasket's suitability will be proven onTrelleborg Bakker's test rig.

FigC

'C''e-ll)5....II) :Gap(mm)

... Typical pressure curve obtained as the gap increasesfor a givendispl ement


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losure forceIt is important to know the forces requiredto compress the gasket as these dictate theforce required to bring two segmentscompletely together.

FigD

:[z:: .CI)f:cu..

meflection(mm)

... Typical load deflection curve

Trelleborg Bakker can provide thisinformation by using one of its compressiontesting facilities which plots the forceagainst closure for a given gasket, expressedas kN per metre (seeFig DGroove dimensionsThe groove is required to locate the gasketin the segment (see Fig E) and is of a sizethat when the segments are closed, (ie nogap), the volume of rubber is housed withinthe groove (see Fig F). If the volume ofrubber exceeds the groove dimensions, itwill not be possible to close the segmentsfully (see Fig G).Trelleborg Bakker's gaskets are designedsuch that the 'el~stomeric material can becompressed to fit within a given groove.The size of the groove therefore has a majoreffect on the choice of TSG and itssubsequent performance.Consultation with Trelleborg Bakker'stechnical personnel will enable optimumgroove dimensions to be determined for aparticular application.

Fig FigF FigG

Ground conditionsA thorough understanding of the conditionsin which the TSGs are required to work willensure that the correct elastomeric materialfor the gasket is made and will resist anydeleterious attack.Trelleborg Bakker's expertise in materialstechnology, along with its long-standingexperience in compounding, will ensurethat the most appropriate material is chosenfor a given application, providingconfidence in the TSG's long-term life.

ittingTrelleborg Bakker's TSGs are manufacturedto fit the grooves of each segment, whateverits size or shape. Fitting is a simple matterof applying the recommended amount ofadhesive to the groove and the base of thegasket, stretching the TSG over thesegment and fitting it into place in thegroove. The adhesive ensures that the TSG

1 is not pulled or jarred our of the groovebefore, or during, tunnel construction.


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orner JointsFigH The corner joints arespecifically designedto ensure they

correspond with theappropriate cornerangle of the segmentfrom aCUte to obtuseangles see Fig H).

FigIornernrelaxedondition ornerfullylosedornerfullyopen

They have been specially designed to ensurethat approximately the same load andclosure forces apply equally to the corner asto the main body of the gasket. In additionto standard quality control procEidures, ,corner joints undergo full opening and fullclosure tests to ensure the integrity of eachjoint seeFig I

dhesivesTrelleborg Bakker will recommend andsupply an adhesive appropriate for bondingits Heinke TSGs to concrete or cast ironsegments. Data sheets relating to theadhesive are available and Trelleborg Bakkercan give further advice on storage andapplication.

TrelleborgTrelleborg Bakker is a member of theTrelleborg Group - a global industrialGroup offering leading-edge expertise inpolymer technology combined withadvanced industrial know-how in respect offunctional solUtions and systems to meetour customers requirements. The Grouphas approximately 21,000 employees insome 40 countries. The Group sHeadquarters are located in Trelleborg,Sweden. Trelleborg AB was founded in1905 and the Trelleborg share has beenincluded in Stockholmsborsen s StockholmExchange) A-list since 1964. Please checkour website for more information:www.trelleborg.com.

~TR LL ORG

ENGINEERED SYSTEMS

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Heinke Tunnel Segment Gaskets

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