Chenab Bridge.pdf

Chanab bridge

2. content

3. INTRODUCTION
•Indianrailwayhasundertakenthemega-projectofconstructionofnewrailwaylineinthe
stateofJammuandKashmir,fromUdhampurtoBaramula.
•Theprojecthasbeendeclaredasanationalproject.
•ThealignmentcrossesadeepgorgeoftheChenabRiver.
•InthedesignworktheNationalcodesofIndia,IndianRailwayStandards(IRS),Indianroad
congress(IRC)recommendationsandIndianstandards(IS)havebeensupplementedwith
internationalstandardslikeBritishstandards(BS),standardsoftheInternationalunionof
railways(UIC)andsomenationalcodes.
•LocationoftheChenabbridgeinReasidistrictofJammuandKashmirinIndia,about600km
northofNewDelhi,(Googlemap-2012)

4. CHENAB BRIDGE PROJECT PARTIES
Clint : KonkanRailways Corporation
Main contractor : Chenab Bridge Project Undertaking
Principal designer : WSP Finland
Structural designer : WSP Finland & Leonhardt, Andraund
Partner
Third-party inspector :Flint & Neil

5. •Theindianrailwayspurposedarailwaylinebetweenkatra(districtofKashmir)andQazigund
(districtofjammu).WhichcrossestheriverChenab.Therefore,itwasproposedtobuildabridge
onthisroute,KnownastheChenabbridge.ThisrailwaylinkwillconnectKashmirandjammu
withinatraveltimeof6hoursand30minutes.

6. Features of Chenab Bridge
ChenabbridgewillbethehighestRailwayBridgeintheworldbeing359mabovetheriverbedlevel.TheChenabBridge
willbe35metershigherthantheiconicEiffelTowerinParis(France).
Morethan1300workersand300engineershavebeenworkingroundtheclocktocompletethebridge.
Theconstructionofthebridgeinvolvedthefabricationof28,660MTsteel,10LakhcumEarthwork,66,000cumconcrete
and26kmMotorableroads.
Thearchofthebridgeconsistsofsteelboxes.Theoverallweightofthearchis10,619MT.
TheChenabbridgeisdesignedtowithstandhighwindspeedupto266km/hour.
TheChenabBridgewillremainoperationalatarestrictedspeedof30Km/hour.
AspertheCentre,theChenabbridgeisbeingbuilt₹1,486Crore.
TheDesignlifeofthebridgeisatleast120years.
Approximately584Kmofweldingwasdonetojointhedifferentpartsofthestructure,Whichistothetuneofthe
distancebetweenJammuTawitoNewDelhi.

7. Mostsophisticated“Tekla”(3DBIMsoftwareformodelingbuildingstructures.)Softwareusedforstructural
detailingofthearch.
Structuralsteelsuitablefor-10°Cto40°Ctemperature
Designspeed:100kmph
BlastresistantdesigninconsultationwithDRDO(DefenceResearch&DevelopmentOrganisation).
DesignedtobearearthquakeforceofhighintensityZone-V
Phased array ultrasonic testing machine used for testing of welding.

8. Components of Chenab bridge
•TheChenabbridgeconsistsofasinglearchof467movertheChenabriverandwillhave
tworailwaylines.Itsdeckwillbecontinuousoverthesupportswithexpansionjointsat
S10,S70andS180supports.
•Theproposedrailwaybridgeconsistsof18piersrestingontheground.Outofwhich4
piersarerestingontheleftabutmentandtheremining14piersontherightabtment.
•Thewidthoftheriveratthebedlevel(RL492m)isabout150m.
•TherailtrackonthebridgewillbeatRL854.517m.

9. Fig-1 Structural plan of the Chenab Bridge

10. Geology Of Site
The Himalayas are full of geological surprise with faults, folds, shear zones etc. present due to ongoing tectonic
activities in the region. The geology at the site of Chenab Bridge are:
The site comprises of shiwaliksand pre tertiary rocks.
The main sub-type of rocks comprises of dolomite and limestone.
Some of the pier locations comprise quartzite and shale rocks.
There are no significant shear zones or cavities in both the abutments.
Top layesof the rocks at abutments are highly fractured and represent a block mass. However, the bottom layers of
rocks are stable and strong enough for a good foundation.
Both abutments have foliation joints with two sets of sub-vertical joints.
The joints are irregular and very rough, with no or little infilling
The spacing between the foliation joints is extremely less.
The rock mass is dry and highly interloked.

11. Rock Mass and Rock Joints Properties
Perliminaryanalysisofrockmasscanbecarriedoutbyfindingvariousrockmassindexes.Suchindexes
characterizetherockmassintofourcategories,i.e:Good,Fair,Poorandverypoorrock.Thecharacterizationof
thesiterockmassbyvariousindexesislisted:
1.Rockqualitydesignation(RQD):49(Fair-Poor)
2.Rockmassrating(RMR) :48(Fair)
3.Q-Index :6.13(Fair)
4.Geologicalstrengthindex(GSI):43(Fair)
Severalin-situandlaboratorytestswerecarriedoutforestablishingtherockmassstrengthanddeformation
properties.ThegeotechnicalpropertiesoftheleftandrightbankabutmentsoftheChenabBridgeare:
Density 2.762gm/cc
Specific Gravity 2.81
Porosity 1.30 %
Unconfinedcompressive strength
(UCS-dry)
160.50 MPa

12. Pointload index 14.12 MPa
Sonicwave velocity 4.60 km/sec
Modulus ofvelocity 4.41x10
4
MPa
Poisson’s ratio 0.22
Cohesion 22.50MPa
Friction angle 58°
Rock-massproperties Rock-jointsproperties
Cohesion (C) 1.40 MPa Cohesion (C) 0.80 Mpa
Frictionangle 44.42° Frictionangle 38°
Bulk modulus 5x10
10
Pa Normal stiffness 4x10
11
Pa/m
Shear Modulus 3.8x10
10
Pa Shear stiffness 3x10
9
Pa/m

13. Foundation and Slope Design
•Thegroundwatertableislocatedfarawayfromthebaseofthefoundation.However,Short-termrainwatermight
developsomehydrostaticpressure.Therefore,theimpactofhydrostaticpressurewasconsideredinthe
foundationanalysis.
•Otherthantheusualloadcombination,ahigherloadfactorwasconsideredforseismicforcesinthefoundation
analysisbecauseofthepresenceofthebridgeintheseismiczone-V
•Forfoundationstability,2-3mdeeptrialpitswereexcavatedforallthefoundationsfromS-10toS-70for
geologicalloggingandconductingplateloadtests.
•Also,formorestabilityoffoundationatS-40andS-5,driftswereexcavatedabout8-10mbelowthefoundation
levelasfoundationS-40andS-50locationarethemostcriticalarchfoundations.Alltheweightofthearcwillbe
supportedbythefoundationlocatedattheselocations.

14. •Isolatedfootingandconcretepedestalwereconstructedforeachsupportonbothsidesoftheabutments.Steel
pierswereboltedusingabaseplateabovetheconcretepedestalofeachfoundation.
•Structuralsteelpierswereusedforthefoundationconstructionofthe18piers.
•Awedgefailureanalysiswascarriedoutatbothleftandrightabutments.Forthispurpose,DIPSandSWEDGE
softwarewereused.
•Apreliminaryanalysisindicatedthewedgefailureatthedownstreamsideofbothleftandrightabutments.Thus,
theriskofwedgefailurewasavoidedbyflatteningtheslopesfrom70°horizontalto63°.

16. Slope Stabilization Measures
Allthe18pierswereconstructedontheslop.Piersprovide
thebasefordeckconstruction,andallthepiersofChenab
bridgearelocatedontheslope.Therefor,toimprovethe
overallstabilityoftheslope,thefollowingmeasureswere
takenforslopestabilization
Afterexcavatingtheslops,a100mmthicksteelfiber-
reinforcedshotcretewasappliedintwolayers50mm
eachtoprovideinstantstability.
Further,aminimumofthreetofiverowsofpassivebolts
of32mmsizeand11mlengthweresetupin100mmsize
boreholesperpendiculartotheslope.Rockboltswere
providedat2.5mspacing.
Also,pre-stressedbaranchorsof625KNcapabilityand
33mlengthwereinstalledin5rowsatS-60pierlocation.
Pre-stressedcableanchorsof980KNcapacityand40m
lengthwereinstalledin5rowsatS-50pierlocation.

17. Forensuringlonglifeoftherockboltsand
rockanchorsupto120years,thefollowing
measureswereundertaken:
Acorrosioninhibitorsolutionwasapplied
totherockbolts.
Further,aminimumgroutcoverof25mm
wasprovidedbetweentherockandthe
bolts.
Thestratumsurroundingthepre-stressed
rockanchorswasgroutedtoreducewater
ingressthroughthesurroundingmaterial.
Thenthepre-stressedrockanchorswere
providedwithdoublecorrosionprotection
sheets.

18. Construction methodology and
sequence
Noelectricityavailablenearthesite,andthewateravailablein
nearbychannelswasnotsuitableforconcreteproduction.
Therefore,electricitywasproducedatthesite,andprovisionswere
madeforsupplyingriverwaterfromfarawaymountains.
Firstly,thefoundationandslopestabilizationworkswerestarted.A
totalof18pierwereconstructed.
Acablecranewillbeusedinthemainspanforthebridgeerection.
Afterconstruction,thecablecranewillbekeptatthesitetobe
usedforrepairandmaintenanceworksinthefuture.
Thebridgeconsistsof25.000tonsofsteelstructures.Steelcolumns
of100mlengthwillbeconstructedwiththehelpofacablecranewith
acapacitytohandleamaximumweightof34tons.

19. ConstructionSequenceofArch
Theerectionprocessofthedeckandarchwillbeproceeding
simultaneously.Boththearchandthedeckwillbemaintainedup
toamaximumcantileverlengthof48m.
Whenthenextarchpiersupportwouldbereached,temporary
cableswillbesetuptosupporttheconstructedarch.Afterthat,
thenewarchpierwillbeconstructedusingthecablecraneson
thefreeend.
Theprocesswillbecontinueduntilthelastpierofthearchis
constructed.
Thefinalsegmentofthearchwillbeconstructedusingacable
crane.Twohalvesofthearchwillbeadjustedusinghydraulic
jacksbeforethefinalconnection.
Finally,thetemporarycableswillberemoved,andthefinal
connectionswillbemade.
Theerectionofthearchwillbe
doneusingderrickcraneand
cablecrane.
Theprocesshasbegunwillthe
erectionofthemainpiersby
cablecrane.Afterthat,thedeck
isluncheduptheaxesof
supportS-40andS-50
Thederrickcranewillbeplaced
ontopdeck.Themaximum
liftingcapacityofthederrick
craneis100tons.

20. A derrick crane is a lifting device usually composed
of mast (frame or tower) and lifting arm.
There are three or four lines connecting the mast
to the lifting arm, which controls it goes up and
down.
Crane cables isa term used to cover a range of
specialist cables powering and controlling
cranes. Used across heavy industry including
mining and marine

21. Arch construction process
Use of Derrick and Cable crane in arch
construction

22. Thehighestrailwaybridge
intheworld:
Uponcompletion,theChenab
bridgewillbethehighest
railwaybridgeintheworld.
Currently,Najieherailway
bridgelocatedinchinaisthe
highestrailwaybridgeinthe
worldwithaheightof310m.

23. Project Status:
Aug2019:80%ofconstructionworkhasbeen
completedonthebridge,andisexpectedtobe
openedinmid2020
Nov2019:83%workhasbeencompletedonthe
bridge,andisnowexpectedtobeopenedin
march2021.
Jan2020:itisnowexpectedtobeopenedin
December2021.
Apr2021:workonboththeendsofthebridge’s
archisfinallycompleted.Itisnowexpectedtobe
openedin2022.
Jun2022:about90%ofconstructionworkhas
beencompleted,andisnowconfirmedtomake
thebridgeoperationalbyDecember2022.

24. •Aug 2022: The bridge’s remaining work on
the final joint was completed, and was
inaugurated on 13 August 2022.
•Feb 2023: Track laying on the bridge starts.
•Mar 2023: The track laying is completed
and a trial run has been conducted on it.
The bridge, along with theentire route from
Jammu to Baramulla, is expected to
become operational by December 2023 or
by January/February 2024.