中国浙江杭州湾跨海大桥 全英文
TheZhejiangHangzhouBaySea-crossingBridgeinChina
The
Zhejiang
HangzhouBaySea-crossingBridgeinChina
FangMingshan
(EngineeringHeadquarterofHangzhou
BaySea-crossing
Bridge)
Abstract:At36totalkilometers,thecurrentlyunderconstructionHangzhouBayBridgeisthelongest
sea-
crossingprojectchallenges
intheworld.Locatedat
severe
entrance
ofthe
HangzhouBay,thebridgeissubjectnumeroustechnical
inthedesign
and
dueto
hydrology,geology,andweather.Thekerneltechniquesapplied
are
constructionofthisproject
Key
presentedinthispaper.Bay。
words:Hangzhou
Sea-Crossing
bridge,Design
&Construction
management,Technical
countermeasure
1
TheProjectBackground
extendthe
TongsanNational
TrunkHighway
across
TheHangzhouBayBridgeprojectwillHangzhou
the
Bay.TheBridgestartsfromHaiyanCountyofJiaxinginthenorthandendsatCixiCityof
Ningbointhesouth.Thetotallengthoftheprojectis36kin.ThenewbridgewillshortenthetripdistancebetweenShanghaiandNingboby120kin.ThisimprovementwillchangeNingbofromtrafileterminalcityinto
a
pivotalcity,and
asa
resultpromoteintegraleconomicdevelopmentwithintheYangtzeDelta.
Figurel.13
DEffect“theBridge
耻m1.2
a
Completed
Bridge.mSouthernTidalLand
are
ThegeometryoftheHangzhouBayis
typicalbugle
shape.Withinthebaytherecomplicatedand
diversetidalflowsalongwithmud,sand,andseabedmovement.Accordingtosurveydata,thehighesttidelevelis5.54mlthehighesttidalrangeis7.57m,andtheaveragetidalrangeis5.32m,tidalcurrentamountis10billionms.Theannualaveragevelocityofflowis2.39m/s.Thehighestvelocityofflow
measuredduringconstructionis5.16m/s
heightof3.23m
on
at
flooding.ThehighestwavemeasuredinAugust2004with
on
a
northernsideand4.72msouthernside.
age
Atsiteofthebridge,thewidthofOffingreaches32km,theshoalatbothsides
a
tidallands,with
seabed
lengthof9.7kmalongthesoutherntidallandand1.4kmalongthenortherntidalland.The
a
terrainofthebayisasymmetricindepthisl3.6m.
Ushape,withtheaveragewaterdepthof8to10m,themaximum
ThegeologyatthesitebelongstotheQuaternary
system
sedimentarydeposit,mainly
tO
comprisingof
mildclay,clayeysand,muddymildclayandsandysoil,withthedepthof130
adversegeologicalfactorsaffectingbridgeconstruction
are
220m.ThetWOmost
widelydistributedshallowlayersofgas
and
PapersofIBC2007一ChinaFeaturedSession
thicklayersofsoftsoil.Thecompressivestressof0.4to0.5MPaandfiredampcontentof85%allowsforthe
possibility
ofbreaking
forth
andburning
The
upper
softsoil
layer
depthis
area
8to
45mandhas
characteristicsofbeingscoured.Theshallowgaslayerisdistributedunderthe
ofsoutherntidalland.
withtheembeddingdepthof40to60m.Groundwaterandseawateratthesitehavemiddle-levelcorrosion
on
thesteelstructure.
ThemeteorologieslconditionsofHangzhouBay
are
complicated.Typhoons,cyclones,thunderstorms
andsmallrangecatastrophicweather
Occur
occasionally.Duringconstruction,typhoonshaveattackedthe
siteseventeentimes.Thewindspeedhavereachedupto35m/s,thewavedepthisupto4m,intheNinthtyphoonoftheyear,Matsa,attacked
on
August6,2005.Becauseoftheinfluenceofwind,wave,flow,
tideandfog,thereisless180workingdaysperyear.
TheBridgeisdesignedinaccordancewiththestandardfor&lanedual-wayexpresswayof33mwidthandtwonavigationchannelsinthenorthandsouthrespectively.Thebridgeforthenorthernnavigationchannelis
a
5-spancontinuoussteelbox-girderdouble-towercable-stayedbridgewithmainspanof448m.
a
Thesouthnavigationchannelis
3-spancontinuoussteelbox-girdersingle-towercable-stayedbridgewith
spans
on
mainspanof318m.Thesuperstructureofapproach
concrete
as
the
seaare
designed
as
70m-spanpre-stressed
are
boxgirders(18.27kin10ngintotal).Theapproachspansatthesoutherntidalland
concrete
designed
use
50m-spanpre-stressed
boxgirders(10.1kmlongintotal).Theprojectisestimatedto
tons
2.45
millionm3ofconcrete,0.82millionofsteel,54070mpre-castpcboxgirders,40450mpre-castpc
boxgirders,and9024piles(3550drivingpilesand5474steeltubepiles).Theconstructionperiodofthe
Drojectis5
years
with
a
totalcostis11.78billionYuaninRMB.
Table1
DesignInstitutes
M面or
Project酶i辨lnstltut嚣andContraeton
Contractors
ChinaHishwayplanningandDesignInstitute(HPDI)Consultants・IncChinaZhongtie
chi胍Zbong。TieMajorBridgeEngineeringGroupCo.・Ltd
TheSecondNavigationalEngineeringBureauofCCCC
ChinaTie鲥uCivil
MajorBridgeReconnaissance&Design
InstituteCo.,Ltd
COccThirdHarborConsultantsCo..Ltd
EngineeringGroupCo.・Ltd
GaogeLandscape
Design&ResearchCenter0fXiarnenChinaRailwayE—HCorporationCRBCInternarional
BeringJiaokeHighwaySurveying。Design&ResearchInstitute
Co..LTD
OuangdongCh蛆gdaHighwayEngineeringCo..Ltd
Forthe
planeand
longitudinal
of
sea
line
arrangementofthe
bridge,many
track
factorswerethe
considered.
Technically,the
distributionarea,current,andchannelaffecteddecision,and
aesthetically。thedesignprinciplesofChineseclassicalarchitectureexhibitedin
West
Lake’sSuBankin
HangzhoucityinspiredthefinalbigS-shapelineinbirdviewplane.
Forfacilitationofbridge’soperationandemergencymaintenance,5emergencyturningaroundand1
serviceplatform
on
the
sea
andrepairingpassagetobearranged.
at
Themeansandmethodsofbridgeconstructionaimed
as
reducingthe
operation
on
the
sea
and
decreasing
constructionrisksmuch
as
possible.InthebridgeportionalongthesoutherntidalIandwith
10kmlong,thelargefloating
crane
wasunabletoworkproperlylackingofwaterdepth;therefore,along
trestlebridgemethodwasadoptedforthefoundationconstruction.Then,asetoflargetypeequipmentwasusedfortransportinganderectingthe50m-spanintegrallyfabricatedpcboxgirders.Inthespans
on
The
Zhejiang
HangzhouBaySea-crossingBridgeinChina
19
thedeepwatersea,totallengthofthatisabout20kmlong,thesteelpipepileswereusedforfoundationand70m-spanpcboxgirder
as
singlepiecewasprefabricated,transportedanderected.
2
KeyTechniquesofthebridge
2.1
KeyconstructiontechniquesofLarge-sizedprefabricatedcomponents
Therewere4kindsofprefabricatedcomponentsdesignedinthebridgeaccordingtotheprincipleofprefabrication,manufacturingandmechanizedequipments.
1.70m-spanintegrallyfabricatedpcboxgirderon
the
sea
A
70meterpcboxgirdersegmentwas
usedforthespans
on
thesea.Eachgirdersegmentwas
fabricated,transportedanderectedinitsentiretyforeach70meterspanandthenmadecontinuousinsitein6—8
spans.Bydoing
so.the540girderswill
actin
a
continuousstaterather
than
simply-supported
spans.The70m-spangirdersare
designed
as
inclinedwebbox
cross
section,withthetopslabwidthof15.
8m。bottomslabwidthof6.25m,girderdepthof4m,anddeadweightof2200
tons.
Thekeytechniquesusedinthecomponent’sprefabrication
are
as
follows
A.Anintegratedinnerformworkoperatedbyhydrauliccylinderassembledindividualsegmentsand
instailedtheminwhole.Theformworkwas1aterremovabelehysectionfolding.
BIAsuccessiverebarbindingandinstallationmethodefficientlyaidedinrebarinstallation.Twocages
ofrebars。oneconsisting
ofbottomslabsandwebsandanotherconsisting
oftopslab,were
fabricated
on
theprefabricatingbedsandthenhoistedandplacedintotheformwork.
C.Aninjectionmoldingtechniqueforlargevolumesofconcretecontrolledtheconstructionprocessof
theboxgirdersandinsuredthegirder’s
construction
quality.
D.Vacuumassistedgroutingandcorrugatedplastictubetechniquewereapplied
to
thelarge-spanpc
boxgirdersforsealingoftheprestressingstrands.E.Anearlyshrinkagecrack
contro[technique
wasappliedsucessfuUytotheconstructionofthepc
boxzirdersin
China.Whenconcrete
reached50%designstrengthvalueand
50%design
vauleof
Eplasticmodule,somepartsoftheprestressedbarson
thewebwerepre-tensionedto1/3ofthe
designvalue.This
loweredtheuniformcompressivestress
on
thesection
whichovercamethe
tensilestressduetohydratingheat
on
thestageofincreasingofconcrete,so
as
torealizecrack
controlledofpcboxgirder.
Thesetechniques
yielded
a
production
capacityof30
girdersfabricated
by
8
prefabricatingbeds
eachmonth.
Figure2.1.170rrrspda
prefabricatedboxgirder
Figure2.1.2
50-spanprefabricatedboxgirder
2)50m-spanintegrallyprefabricatedboxgirder
at
southerntidalland
Originallyforthe50mspan
on
thesoutherntidallandssimplysupportedgirderswere
considered,but
PapersofIBC2007一ChinaFeaturedSession
superstructure.Thissuperstructureconsistedof26
a
a
continuousgirderwaseventuallyadoptedforthe
continuous
units,eachmadefromthe404piecesof50mgirders.Thissectiontotals
s
lengthof10.1kin
withminimum6000mradiushorizontalcurve.Theboxsectionhas
top
slabof15.8mwide,abottomslab
toil.The
prefabrication
of6.625mwideandsectiondepthof3.2m.Theweightofeachpieceis1430techniquesforthe50mspandifferencestothattechnique
are
essentiallytheasme
as
as
70m-spanpcboxgirdermentionedabove.Theonly
are
followaI
can
A.Becauseimpropertemperatureandhumidity
affectthedurabilityandanaphasestrengthofthe
concrete.measureswereusedtoregulatetheseconditions.Inordertocontrolinternslandoutsidetemperatureandhumiditydifferencesofthe
concrete
at
eachcuringstage,thetemperaturewas
beingkeptat350C士5andhumiditywasregularlymaintainedwithsteam.B.To
moreadequatelytakeadvantage
ofthe
a
storagespace
ofthe
castingyard,the
use
finished
prefabricated
yard.
boxgirderswerestoredindouble-deckfashion,maximizingtheofspaceatthe
Thesetechniquesresultedineachmonth.
a
productioncapacityof30girderconstructedfrom6prefabricatingbeds
3)Low-HeightPre-CastPierShaftThelow-Height
pre-cast
on
theSea
weredesigned
440
as
piershafts
a
hollowthin-wall
rectangular
piers,with
maximumheightof17.4mand
ina11.Thetopsectionsizeofappliedinfabrication
are
as
a
maximumweightoftons.Therewere474piecesoftow-heightpiers
standardpieris6.25m×4.0m.Forthistopsectionthekeytechniques
follows:
aa
an
A.Innerformwork:Theinnerformworkforthepre-castshaftwasdesigned
with
a
integralformwork
at
segmentalumbrellashapetolimitshrinkage.Theinnerformworkis90cminheight
the
straight—linesectionand100cminheightatthevaryingwasunfoldedB.Theoutside
on
section.When
assembled,theformwork
thegroundandtheneachsectionwasconstructedfrombottomup.
bars
are
formwork:Sincepull-onreinforcement
prohibited
on
thebasisofanti—
formwork
erosion。aateeltrussformworkwasconsistedof
a
adoptedfortheoutsideformwork.Theoutside
a
panel,verticalwroughtiron,transversesteelplatesandsupportingtruss.After
as
thereinforcementswerebound,theoutsideformworkwasassembledbythesamemethod
inner
formwork.
C.Steelbracket:Becauseofthe
lengthofoutside
reinforcements,a
special
ateelbracketto
be
designedwiththeheightof1.2rmThesetechniquesresultedin
per
a
productioncapacityof20pre-castpiersfrom5prefabricatingbeds
montIL
4.Spiral-WeldingIntegralRolledSteelPipePileUsedforPierFoundation
on
theSeadesigned
as
Thefoundationsforthemiddleapproachspansandsouthernapproachpiers
are
steel-pipe
pile,withthediameterof由lS00mmanddpl600mm,thelengthofpilevariesfrom71mto88m,withtheheaviestpileweighing73tons.Inallthere
Thesteel-pipepilehavebeenappliedexceed60m;however
on
are
5474pilesutilizing37・000tonsofsteel.
on
theinshoreportprojectsofChina.Usuallyitslengthsdonot
a
theDonghaiSea-crossingBridgeprojectthelengthdidreach
maximumof77m.
a
Themanufacturingforthekindofpileisbyring-weldingjointedmethod.Thisrequires
largeindoorfield
andlargeassemblingjointedequipment.Assemblingneedsmanualweldinghavelowworkefficiencyandvarying-thicknessringweldingdevelopsweakpoints.As
a
result,asuperqongvary-thicknesssteelplate
TheZhejiangHangzhouBaySea-crossingBridgeinChina
21
Figtire2.1.3
Constructionof
pre-cast
m盯
manufacturetechniquewasdeveloped,whereconnection
problemsforvary-thickness
platewere
solved
duringthepile’Sfabrication.On-timepre-exactweldinganddouble-facedembedmentwereusedinspiralwelding.
Steelpilesprotectionand
are
arc
weldingmethod
mainlyprotectedfromcorrosionby
a
surfacecoatingandsupplementedwithcathode
complexmeltingcombined
tO
appropriatelypreservedsacrificialthickness.Amulti-layered
withimprovedepoxycoatingtechniquewasadoptedforthesteelpilecoating.Inorder
strengthenthe
stiffness,improveanti-corrosionandanti-shipcrashingperformanceoftheuppersectionofpile,concretewaspouredintothepilesatelevationsabove一12.Orn.Theproductionstreamlineprovidedsurfaceanti-corrosioncoating.
There
are
a
three-layer
threeproductionlines,thatcouldfabricate283pilespermonth,with
a
fabricatingrecordof
14andthebestcoatingrecordof15piecesperday.Thefabricationoutputwasabletokeepuptheneedsofdrivinginthesite.
脚u”2.1.4a
2.2
ManufacturingofSteel-pipepileFigure2.1.4b
CoatingofSted-#pepile
TransportingandErectingTechniquesofLarge-SizedPre-CastComponents
sea
1.Erectionofintegrallypre-castboxgirderattalbheightpiersat
Acustom-made“LittleSwanFloatingCrane”wasusedfortheerectionofpre-castboxg【rderslower-heightpiers,whichhasliftheightof30m.Inthe
area
on
the
oftall-heightpiers,theLittleSwanCrane
couldnotsatisfytheconstructionrequirementsofthepiersbecauseitwasrestrictedbyliftheightandhigh
flowvelocity.Therefore。the。TianyiFloatingCrane”wasdesignedandmanufacturedfortalbheightpier
erection.TheTianyiCraneis93.4min1ength,40.0minwidth,53minliftingheight,has
a
3000ton
r
liftingcapacity,over8.2knotinnavigationspeed,Class7Beaufortscaleinoperationalwindforce
Class
8
PapersofIBC2007一ChinaFeaturedSession
in
transportationwindforce,and2.0m
inwave
On
could
Beaufortscale
transport
height.average
onecrane
anderect1to2girderseachday.
as
Themainconstructionprocedureforerectionofpre-castboxgirderwasA.LoadingthegirderfromtheshipyardB.Sailingthegirderoutto
sea.
follows:
eAnchoringandlocating.
D‘Installingthegirder
on
thetopofpier.
E.BackingOuttheshipandfloatingitawayfromthesite.F.Preciselyplacingthegirder.
Figure2.2.1a
LittleSwanCraneFigure2.2.1b
on
TianyiCrane
2.Transportationanderectionofintegrallypre-castboxgirderAtthe
southerntidalland。thetransportationofthe
thesoutherntidalland
boxgirderincludedfield-transferringofthe
girdersfromthefabricationbedtothestoragebed,andfromstoragebedtoelevatingstation,elevating
fromground
to
bridgedeck,andlong-distancetransport
cases:
onthe
bridge
deck.Different
types
of
transportationequipmentwereadoptedfordifferent
A.Two800tontirecarrierswereimplementedforgirdertransportattheprefabricationyard.The
carriers
are
designed
as
wheel—type
transporting
equipment.Itconsistsof
a
maingirder,
supportinglegs,operationsystem,liftingsystem,girder-hangingcarriers,powersystem,
hydraulicsystem,electricalsystemetc.
B.ThegirderwaslifteddirectlyfromgroundtObridgedeckbytwo800tonwheel-railcarriers,whichconsistsofmaingirder,rigidsupportinglegs,flexiblesupportinglegs,girder-hangingcarriers,electricalsystemandcontrollingsystemetc.Itsfunctionswereliftingthegirderfromthegroundtobridgedeck
0n
the
site,movingthegirdertransversely,automaticloadequilibrium,assembly,
disassemblyoftransportingequipmentandbridginggantry.C.ATE1600girdercarrierwas
usedtotransportofthegirder
on
the
bridgedeck.Itincludes
a
mainframe,wheelgroup,bearingbeam,hydraulicassistantsupportinglegs,turningset,balance
system。electricalsystem,powersystemetc.Inaddition,ithad
bearingbeam,backbearingbeamdesignedsupport,whichcould
as
a
singlecarrierconnectingby
as
fixedsupport,frontbearingbeamdesigned
rolling
realizesecondarylongitudinalmovement.
a
D.Bridginggantrywasusedforerectionofgirder,whichconsistof
carrier,fore-and-aftsupporting
mainbeam,girder-hanginglittle
legs,power
over.
set。electricalsetandetc.Ithasfunctionofgirder
1ifting,moving,installingandspanning
TheZhoiangHangzhouBaySea-crossingBridgeinChina
23
Figure2.2.2aMLB00tTyrecarrier
F'增ure2.2.2bHMa00tdevatingmachine
Figure
2.2.2c
TEl600Tyre
transportingequipmentFigure2.2.2d
LGBl600tBridgeGantry
3
InstallationofPre-castpier
onthesea
Theheaviestpre-eastpierweighs440tonsandmeasures17.38minheight.Theoriginal
as
crane
chosen
theinstallingshipfor
pre-east
piershad
a
weightlimitof300tonsandheightlimitof10.6m,whichhas
lengthof58.86m,widthof27m.Sincethepre-castpiersforthisprojectexceed10.6minheightand300
tons
inweight,a
crane
withliftingcapacityexceed500tonswasused.
Inordertoinstallpre-castpiers,specialdesignswerecarriedoutfororientationbearing,liftingtools,andmanholesatthetopofpier.There
are
threekeyproblemstobesolved
as
followings:
A.Pier’Storsionproblem,whichwassolvedbytowingropeto
connects
adjust
on
torsionangleofpier.Therope
with
a
winch
on
the
crane
shipthrough
a
manhole
thepier’Stop.
are
B.Temporaryfixing
problem.Whilethepieristillingitsshoes,custom—madeclips
on
usedto
connect
released.
thepierwithpre-setreinforcements
thepierbase,allowingfortheliftingtooltobe
CInstallingprecisioncontrollingproblem.Inorder
to
prevent
eccentricstress
axes
on
the
pier.the
installationofpre-castpierwascontrolledintwo-wayswithgradientand
adjustments.
Figure2.2.3apm-cast
pim
F培ure2.2.3b
Hoistingof
pre-cast
pier
PapersofIBC2007一ChinaFeaturedSession
D.Constructioncontrollingproblemofwet-jointingsection.Bytakingsetsofmeasurements,such
as
optimizing
concrete
mixedratio,imbeddingfibersintoconcreteat
an
optimalamountof0.9kgper
cubicmeter,addingupreinforcementsatoutsidehoopsandetc.,shrinkagecrackwaseffectivelycontrolled
on
thewet-jointingsection.
4
PilingofSuper-longspiral‘weldingsteelpipe
pile
Thefoundationunder
a
singlepierofapproachspansat
sea
are
designedwith9to12pileswiththe
diameterof1.5m
or
1.6m,layinclubsshape,andmaximumsloperatiois6:1.Undertheabominable
are
conditionsofHangzhoubay,theconstructionprogressofthepileisrestrictedbytheequipment.There7pilingshipsusedintheproject,allofshipspowerhydraulic
or
are
equippedwithGPSpilingorientationsystemandlarge
andTianweiPilingShipshave
dieseldrivinghammer.Amongthoseships,Haili801
are
nearlythesameequipment,bothofthem
equippedwithmostadvancedmulti—functionfull-whirlypile-
sea
drivingcrane.Haili801is80m10ng,30mwideand6mtall,with2.8m
gaugeandequippedwith86m
士18mhighpilingbracket,four1.5×1.5×30malignmentstakes,GPSpilingorientationsystemand
automaticmovingequipment.
Figure2.2.4a。Haili801”BoatFigure2.2.4b。Tianwd"Boat
SincethefirstpiledrivingofNovember2003,allthepilesweredrivenwiththemonthlyaveragepilingof260.Thepiledrivinghasbeenfinishedmorethan1yearaheadoftime.
2.3
Structuredurabilityprotectiontechniques
Investigationofthecorrosionsituationofexistingmarineconcretestructuresatthebridgesiteshowedthatpenetration
ofchlorine
ion
is
the
main
factor
influencing
structure
theconcretestructure’s
durability#
for
therefore,multi-layerintegrated
measuresof
concrete
durability
havebeendeveloped
differentsectionsoftheproject.Theyconsistofbasicmeasures,additionalmeasures,supervision,andevaluationmeasures.
A.Basicmeasures:Overall
thechlorinediffusive
a
specialdurable
marine
a
structuralconcretewasdevelopedbyrestricting
a
coefficient
andsetting
reasonableprotectionlayerthicknesstosatisfy
designservicelifeof100years;aspecialdurableB.Additionalmeasures:Depending
wereadoptednamely
on
marine
structuralconcretewasdeveloped.
thedifferenteasesandenvironments,someadditionalmeasures
concrete
surface
coating,controlledpermeabilityformwork,epoxy
an
coating
are
rehar。ananti—immigration
agent,andalso
impressedcurrentcathodeprotectionscheme
adoptedforsplashingzoneinthethreemainpylonsofchannel
bridge.
TheZhejiangHangzhouBaySea-crossingBridgeinChina
25
C
Monitoringmeasure:B,setting
pre-buried
to
concrete
a
durabilitymonitoringsystem,dynamic
parameterswerecontinuouslyobtained
D.Evaluationmeasure;Bysetting
checkedandvalidated.
an
make
concrete
durabilityschemefortheproject.
tobe
exposuretrialstation,thedurabilitymethodswereable
1jgure2.3.1aTrapezoidanodepM-buried
SellgOr
F*ure2.3・lb
Titaniumwiremesh
2.4All-weathersea-crossingsurveyorientationtechnique
SincetheCOnstruction
exact
area
spans32km,traditionalsurveymeasurescouldnotappropriatelydetermine
survey
pileslocation.Therefore,thefollowing
measuresweredevelopedandimplementedt
A.GPSReferenceStation:AcontinuouslyoperatingGPSreferencestationsystemwasinstalledto
supplyimportantinformationtocontractors.
I.Thesystemcouldsupplystaticsurveydatawithin24hrs.Thisconstruetion.controllingnetworksfoundatlocal
couldbeusedforlayingout
constructionanddisplacementmonitoring.
an
Thesystemcouldalsoobtainthereal-timeplanelocationwith
accuracyof
3to5cmandreal-
timeelevationlocatingwith
an
accuracy
of5to10cm.
2.Thesystemcouldsupplyfastandexacttechnicalserviceforstructuralhealthmonitoringandhighlyprecisedisplacementmonitoringserviceduringtheperiodofprojectoperation.
B.54independentengineeringsurveyswerecoordinatedinto
a
system,SO
asto
solvetheproblemof
largelengthdistortion(4.559mshorteninlength)sincethedesignthebridgewasmadein1954.
C.HighprecisionGPSelevationfittingwasappliedtocontrol
Theaccuracy
ofthis
method
reachedGradeIII
Beijing
CoordinateSystemusedtO
。
construction
elevationproblemsat
the
use
sea・
levelprecision
without
ofany
public
elevationsurveyingpointfromwhichtoreference.Thispreventedtheerectionofsurveyingplatforms
on
a
fewlarge-sized
thesea,thussavingobservationtimeandconstructionCOSt.
Figu"2.4.1a
Surv咖orientation
Figure2.4,lb
GPSreference
station
26
PapersofIBC2007一ChinaFeaturedSession
2.5
DrivingSafetycontroltechniquesforbridgeoperation
Duetothespecialenvironmentcondition,thebridgeisfacedwithcatastrophicclimates.Thisresultsinsomekeyproblems.Howwillprojectorganizationandeconomybenefitsbeinsured?HowwilIdrivingsafetybeensuredwhilemaintainingthebridge’Strafficcapacity,whichmustalsoatleastreachthesamelevel
as
theconnectionofhighwaysatboth
on
banks?Toanswerthese,animpactstudyofcatastrophic
climatedrivingsafetyandstudyofstrategieshavebeencarriedoutsince2004.Amainconcentrationof
on
thestudyanalyzedtheimpactofcatastrophicweathervalidoperationperyear.
Thestudyalsofocused
on
drivingsafetyinordertofindoutthetotaldaysof
theengineeringandmanagementmeasurestoimproveoperationservice
a
level,anditscorrespondingeconomyindex.Intermsofsafety,thestudyaimedtodevelopdrivingsafety8afeguardingsystem.
schemeof
Bycarryingoutabovestrategies,severalengineeringmeasureshavebeendeveloped.Theheightofhandrailhasbeenadjustedfrom1.2mto1.5m.Thewindshieldingfunctionofthecrossbeamspaceofhandrailswasalsoconsideredinthisdecision.Height_varyingwindshieldsinstalleddirectlyhandrails
are
on
thetopof
designedinthechannelbridgesanditsadjaeenttall—heightpiersarea.Lastly,forthesakeof
on
drivingsafetyfoggydays.foglights
are
designedaccording
tO
space
ofroad1ampsatbothhandrails.
Figure
2.5.1aHandrailscombinedwith
oN
Figure
2.5.1bWindshields
oil
the
wmd-shields
thechannelbridge
approach
qⅢwithtall-heightpier
2.6
Constructioncontrollingtechniqueofnaturalgas
wasfound
gas
on
on
thesoutherntidalland
during
the
originalgeological
investigate
the
Naturalgas
thesoutherntidallandof
bridgesitein
the
cause
investigation.Natural
hadbroken
through
outto
strongly
CZK30hole.To
phenomenon,aseriesofstudieswerecarried
gas,analysisimpactgas.Thefollowing
A.A
shallow
on
discoverthe
offormationbyanalyzingof
naturalnatural
theproject,andanalyzecorrespondingengineering
obtainedfromthestudies.
gas
countermeasures
ofthe
conclusions
1ayer
ofbiologic
is
widely
developed
atthe
Quaternarysystem
over
sea
fascias
a
sedimentarydepositintheHangzhouBayarea.Thisshallowlayerisdeveloped
area
suchvast
thatitwouldhavebeen
unavoidable
even
ifthebridgealignmentwereadjusted.
are
B.Theimpactofnaturalgascouldbe
to
overcomeifactivemeasures
adopted;itisdefinitelyfeasible
buildbridgeinthe
natural
gas
on
gone.
C.Theimpactofthenaturalgas
pile’Sdrivingis
small
whiletheimpact
on
boringpileismuch
moreseverely.Thetechniquemeasuresshouldbeadoptedwhilepileboring.D.Thebestvalidwaytopreventthenaturalgasfromeruptingistoadopt
an
activecontrollablegas-
releasingmeasure.
E.Based
on
thegasstoragetechniquesavailableinChina,9gasreleasingpoints
on
thebridge
site
TheZhejiangHangzhouBaySea-crossingBridgeinChina27
havebeendetermined.Thegas-releasingpoints
bridgeaxesarelocatedatupstreamanddownstreamofthewithadistanceof20m,2pointsperpiertobearranged.Thegasreleasingworkwill
begin3monthspriortothestartoffoundationconstruction.
Figure2.6.1dNaturalgaseruptingFigure2.6.1bNaturalgasburning
3Conclusion
Sincestartingtoconstructionoftheproject,keytechniquesofthebridgedesignandconstructionhavebeensolvedsuccessfullyandtheprojecthasbeeningoodprogress.Thishasbeenduetoproactivepreparationtechniqueandgeneralschemeofrationalbridgedesignandconstruction.Presently,9.63billionYuanRMBoftheinvestmentfundhasbeenfinished,theprojectwillbestructurallyconnectedonJune30,2007,andopenedfortrafficonJune
30,2008.