Metro elevated structures AR.pdf

The presentation is on need for mass rapid transit system, types of MRTS and Civil structures in Metro rail system.

1. Civil Structures
in Elevated Metro Rail
System
By
AshutoshRankawat
CGM/P&D
Gujarat Metro Rail Corporation Ltd.

2. Need for Mass Rapid Transit
System

3. Need for Mass Rapid Transport (MRT) System
Today,aboutsome56%oftheworld’spopulation(Totalpopulation8.0billion)i.e.
about4.5billioninhabitantsliveincities.Thistrendisexpectedtocontinue,withthe
urbanpopulationmorethandoublingitscurrentsizeby2050(70%oftotal
population).

4. Need for Mass Rapid Transport (MRT) System
Thereisnouniversaldefinitionofwhatconstitutesan‘urbanarea’;definitionvarywidelyacross
countries,bothintermsofthemetricsusedtodefinethem,andtheirthresholdlevel.
Thedataofshownforagivencountryinthemaponpreviousslideisitsnationally-definedminimum
threshold.2000and5000inhabitantsarethemostfrequentlyusedthresholdlevel(by23countries
each).However,theserangesvarywidely.133countriesdonotuseaminimumsettlement
populationthresholdintheir‘urban’definition.Someuseavariationofpopulationdensity,
infrastructuredevelopment,orinsomecasesnocleardefinition.

5. Need for Mass Rapid Transport (MRT) System
By2030,theworldisprojectedtohave43megacitieswithmorethan10million
inhabitants,mostofthemindevelopingregions.However,someofthefastest-growing
urbanagglomerationsarecitieswithfewerthan1millioninhabitants,manyofthem
locatedinAsiaandAfrica.
However,thespeedandscaleofurbanizationbringschallenges,suchasmeeting
accelerateddemandforaffordablehousing,viableinfrastructureincludingtransport
systems,basicservices,andjobs.

6. Need for Mass Rapid Transit (MRT) System
The percentage of Urban population in India is reported at 35.87 % in 2022
and it is expected to be more than 50 % by 2050.
Due to urbanization, Indian cities are growing rapidly and witnessing fast
growth in the number of personal motor vehicles causing severe strain on
existing road transport infrastructure.
This is resulting in severe road traffic congestion and air pollution.
Hence, more & more cities are experiencing need for Mass Rapid Transit
(MRT) system to meet their ever increasing demand of public transport &
mobility requirement.
Metro rail, which provides high capacity public transit, has seen substantial
growth in India in recent years.
As on date:
(i) 870 Km. metro is operational
(ii) 462 Km. metro is under construction
(iii) 372 Km. metro approved

7. 25km
248km
Growth of MetroRail…
First modern energy efficient ACmetro
services started in Delhi; 8 km stretch
between Shahdra and TisHazari
1984
FirstmetroservicestartedinKolkata-
asmallsectionof3.4kmunderground
metronetwork;12yearstoconstruct
Prior to 2014, about 248 km metro network was operational in 5 cities. 484 km operational metro network added during 2014 to 2021 in 18cities
2002
Majorthrust throughPolicy,Planning,Options,Financing,Innovationsand
‘Make inIndia’
2014
Growth of Operational Metro Network in thecountry
2021
5
0km
1city
2cities 5cities 18cities 27cities
Item Before2014Addition after2014 CurrentStatus
No. of cities with operational MetroNetwork 5 13
18
1,70
Commissioning of new metro rail lines(km) 248 454 702 733km
Approved metro networks, including RRTS for construction(km) 659 1,059 1,718
operational
metronetwork
Approved RRTS corridor for construction(km) 0 82 82 202
Metro passengers per day (ridership in lakh) 17 68
85
(pre-Covid19)

8. Metro RailSpread
UnderConstruction Operational
Bhopal
Indore
Patna
Agra
Delhi &NCR
(8cities)
Ahmedabad/
Gandhinagar
Surat
Mumbai, Thane&
NaviMumbai
Pune
Bengaluru
Jaipur
Kochi
Chennai
Hyderabad
Nagpur
Kolkata
Lucknow
Kanpur
Meerut
RRTS
MetroRail No. of Cities
Operational 18
Under Construction 15

9. Mass Rapid Transit System

10. Mass Rapid Transit System
A Mass Rapid Transit System is a public transport system in urban area
with high capacity and high frequency
is fast and
is segregated from other traffic (operates on exclusive Right of Way or
grade separated)
Rail Rapid Mass Transit System:
Light Rail Transit
Mono Rail
Metro Rail

11. Systems of Public Mass Rapid Transit Systems
City
Populati
on
Peak
Hour
Peak
Direction
Traffic
Avera
ge trip
length
Mode of
Transport
System Remarks Photograph
1 –2
Million
4000 -
10000
> 5
Km.
Bus Bus
Rapid
Transit
System
Dedicated path / lane
with continuousfencing
/ Kerbseparating the
road traffic with BRTS
lane.
1 –2
Million
≤ 10000 > 7
Km.
Rail
Rapid
Mass
Transit
System
Light
Rail
Transit
(LRT)
Rail guided or rubber
tyredcoaches powered
by overhead traction
system running on a
road slab either at-
grade or elevated. LRT
at grade :-Continuous
fencing / raised Kerb
separates the road
traffic with LRT lane.

12. Systems of Public Mass Rapid Transit Systems (Contd.)
City
Populati
on
Peak
Hour
Peak
Direction
Traffic
Avera
ge trip
length
Mode of
Transport
System Remarks Photographs
> 2
Million
≤ 100005-6 Km.
Rail
Rapid
Mass
Transit
System
Mono
Rail
Monorail trains
(electrically propelled
rubber tyredrolling
stock) operate on
dedicated corridors
on grade separated
concrete track beams
(guide-ways).
>2
Million
> 15000> 7 Km. Metro
Rail
Electrically propelled
coaches operate on
grade separated
(Elevated /
underground)
dedicated corridors.

13. Bus Rapid Transit System
Light Rail Transit Metro
LRT metro (Metrolite) have lighter coaches (11 m long &
2.65 m width) of 12 t axle load. A train set consists of 3
coaches, with total passenger carrying capacity of around
300 passengers.
Elevated LRT system is planned only when At-Grade system
is not feasible.
Maximum operational speed is 60 Kmph.
BRTS:-Can be provided where the roads are wide and have
sufficient space. Passenger carrying capacity of a bus is 90
passengers.
Elevated LRTLRT at Ground

14. Mono Rail System
A monorail is a rail-based transportation system
based on a single rail, which acts as its sole support
and its guide-way.
Each train consists of either four or six cars with
a capacity to accommodate 568 passengers (4 cars) &
852 passenger (6 cars) at a time.
A 4-coach monorail train has a total length of 44.8
metresand each coach weighs 15 tonnes.
Maximum Operational speed: 80 Kmph.

15. Mono Rail System

16. SkybusMetro System
The system consists of an elevated track
with 2-3 cars suspended below.
8 m x 2 m steel box beam/girder, supported
on 15 m –20 m spaced columns, carries
standard gauge track.
Each coach is 9.25 m long and 3.2 m wide
with passenger carrying capacity of 150
passengers.

17. SkybusMetro System

18. SkybusMetro System

19. Metro Rail System
A train set consists of either 3 coaches or 6 coaches.
(Coach dimension: 21.34 m –21.64 m. length, 2.9 m
width & 3.9 m height and 16 t axle load). Passenger
carrying capacity of a train set of 3 coaches: 764 (at 6
standee/sq.m) & 972 (at 8 standee/sq.m)
Maximum operational speed: 80 Kmph.

20. Elevated metro viaduct on central median of road

21. Major difference in construction of Metro rail and
normal Railway line
Metrolinesaremostlyconstructedincongestedurbanareas.
Sincemetrolineisconstructedinurbanareas,majorchallengesinits
constructionare:
(1)Constraintsinconstructionduetolimitedworkingspace(incongested
urbanarea),limitedworkinghoursfortransportationofmaterialsto&from
site(duringnighttimeonly)andforactualconstructionactivities(during
daytimeonly).
(2)Dealingwithlargenumberofsub-surface,surfaceandoverheadpublic
utilityservices,viz.sewers,watermains,stormwaterdrains,gaspipelines,
telephonecables,electricaltransmissionlines,electricpoles,trafficsignals
etc.fallinginmetroalignment:-Eitherredesignofmetrostructuresor
shiftingutility/supporting&maintainingthemduringconstruction.
(3)Regulationofvehiculartrafficduringconstruction.

22. Civil Engineering Structures in
Metro rail System

23. Civil Engineering Structures in Metro rail
Fromconstructionpointofview,metroCivilEngineering
Structurescanbebroadlyclassifiedinto:
(A)Elevated
(i)Viaduct
(ii)Station
(B)Underground
(i)Tunnel
(ii)Station
(C)Maintenancedepot

24. Elevated Viaduct

26. Pile Foundation

27. Construction of Pile foundation
•Generally,inmetrorailconstructionboredcastinsituR.C.C.pile
foundationof0.8m,1.00m&1.20mdiameterwithvaryingdepth(22m.
to32m.),dependinguponfoundationsoilproperties,areused.

28. Construction sequence of
cast-in-situ
RCC bored piles

29. Stage 1: Bore drilling by rotatory
drilling machine Stage 2: Lowering of Rebar cage
Stage 3: Concreting using Tremie
Photographs showing construction sequence of cast-in-situ RCC bored piles

30. Piers

31. Construction of Piers
•Metropiersaregenerallycast-in-situReinforcedCementConcrete
(RCC)structure.Theyaregenerallycircular,oblong,squareor
rectangularinshape.

32. Types of metro pier
•Normal (concentric) pier, Cantilever pier or Portal pier
Normal Pier and Cantilever Pier Portal Pier
Cantilever
Pier
Normal
Pier
Portal
Pier

33. Pier Cap / Pier Arm

34. Construction of Pier cap and Pier arm
•Piercapiseithercast-in-situRCCorprecastposttensionedPrestressed
Concrete(PSC)structure.Butnow,mostlyprecastposttensioned
PrestressedConcrete(PSC)isusedforbothpiercap(viaduct)andpierarm
(stations).
Cast-in-situ Pier cap construction

35. Launching of Precast Pier cap
Launching of Precast Pier arm

36. Bearings

37. Bearings
•Abridgebearingisanelementofsuperstructurewhichprovidesaninterfacebetweenthe
superstructureandsubstructure.
•Bearingperformsthefunctionof
(1)allowingtranslationandrotationalmovementofsuperstructuretooccurand
(2)transferstheentireloadfromsuperstructuretothesubstructureofbridge.
•TypesofbearingsinMetrorail:
1.Elastomericbearing:AnElastomerisapolymericsubstanceobtainedbyvulcanizationofrubber.
Elastomericbearingconsistsofelastomerlayerswith1mmto3mmthicksteelplatesbetweenthe
elastomerlayersbondingfirmlywiththeelastomer.Usedforbridgespanupto45.7m.

38. Bearings (Contd.)
2.POT-PTFEbearing:Usedforrelativelylargerspan/heavierload.PTFE(PolyTetraFluoro
Ethylene),alsoknownasTeflon,isahard&durablematerialanditpossesseshigh
chemicalresistance.TheelastomerpadinsidethePOTprovidesrotationalmovementby
differentialcompressionofelastomer.Thetranslationmovementtosuperstructureismovement
isprovidedbysteelplateslidingoverPTFE.ThecoefficientoffrictionbetweenPTFEandstainless
steelisthelowestbetweenanytwomaterialswithinthenormaltemperaturerange.

40. Bearings (Contd.)
3.Spherical Bearing:It consists of a set of concave & convex
steel backing plate with a low friction sliding interface (PTFE) in
between
(i) permits rotation by incurve sliding,
(ii) for providing sliding movement, the bearings may be combined
with flat sliding elements, guides and restraining rings.
SphericalbearingisprovidedinMetrorailwaybridgeswithspans
of61m.ormoreorinopenwebthroughgirderswherehigh
rotational&slidingmovementareneededandthevertical
loadtransmittedthrougheachbearingistoolarge.

41. Components of Spherical bearing

42. Girder / Truss

43. Girder or Truss
•Different types of girders and Truss used in metro are:
1.Segmental precast pre-stressed Concrete (PSC) box girder:Number of precast PSC
box segments each of 2.5 m. to 3.0 m length are post tensioned at site. Used for
spans of 22 m. to 37 m. and up to sharpest curve of 140 m. radius. Precast PSC box
segments weighing about 35t to 50t are casted in casting yard, transported to site,
erected in position & segments are stitched together by post tensioning. Suitable
for metro viaduct construction in congested city areas.

44. Match casting of PSC box segments in casting yard Stacking of casted segments in yard
Transportation of box segments to site Erection of box segments using launching gantry
Construction sequence of Precast PSC box segmental bridge

46. Girder or Truss
2.Precast pre-stressed Concrete (PSC) U girder:U girders are precast post tensioned U
shape concrete girders of length varying from 16 m. to 28 m. (weighing about 100 t
to 165 t each) casted in single piece for one track of a span. Can be used in curves of
radius more than 400 m. Girders are casted in casting yard, transported to siteand
erected in position using lifting cranes.
U girders are not suitable for viaduct in heavy congested areas due to problem in
transportation of long girders to site of erection (difficulty in manoeuvringof
narrow lanes by long road trailer.)

47. Casting of U girders in casting yard
Transportation of U girders to site
200 MT road trailer
Stacking of casted U girders in yard
Erection of U girders at site by cranes
Construction sequence of Precast U girder bridge

48. Girder or Truss
3. Precast pre-stressed Concrete (PSC) I girder:Precast post tensioned I girders are generally
used on sharp curves in viaduct, where PSC box girder & U girder can not be used and in
stations / approach spans of stations, housing points & crossings. PSC I girders are used for
span up to 31 m.
PSC I Girders on long spans
PSC I Girders on sharp curve
PSC I Girders in casting yard

49. Girder or Truss
4. Steel I girder composite superstructure:Steel I girders with RCC deck slab are used
for spans more than 34 m. Steel I girders are fabricated in workshop, transported at site
and erected on span using cranes. RCC deck slab is casted at site on the I girders. Used
for span up to 47 m.

50. Girder or Truss
5.Steel truss composite superstructure:Steel trusses, generally known as
open web girder (OWG) with RCC deck slab are used for spans more
than 47 m.
Truss members are fabricated in workshop, transported at site and
assembled at site.
Assembly of fabricated members at site on scaffolding

51. Girder or Truss
•If OWG is to provided spanning a busy road or railway tracks, it is not possible
to assemble the truss on its final location. In such cases the truss is assembled
on one side of the abutment of bridge and then incrementally launched on its
final position. RCC deck slab is casted at site on the launched truss.
Assembled Truss with launching nose on scaffolding
Launching nose

52. Launched Truss at its final position

53. Girder or Truss
6. Cast-in-situ PSC segmental balanced cantilever bridge:The Balanced Cantilever
method is a construction method in which PSC box segments of superstructure
are sequentially joined to form a span by post-tensioning and balancing them
left and right from each pier using special erection equipment. The method does
not require scaffolding systems under the bridge Used for longer spans; more
than 47 m.

55. Launching of PSC segmental Box girder superstructure
Lifting beam
Main Components of launching gantry

56. Middle support

57. Step 1:
1.Middle support is moved slightly
ahead to make room for rear
support to take its position.
2.Rear support is moved ahead.
Active

58. Step 2:
1.Rear support is moved up to pier
location. Lifting front support from
telescopic leg
2.Lifting front support from telescopic leg
ActiveActive Active

59. Step 3:
1.Middle support is moved to the
edge of erected span
2.Telescopic leg is removed.
Active

60. Step 4:
1.Launching gantry is moved ahead.
2.Rear support is moved close to middle
support
3.Telescopic leg is erected on pier ahead
Active

61. Step 5:
1.Front support of launching gantry is supported
over telescopic leg on pier ahead
2.Sliding beams and hangers are moved towards
front support
ActiveActive

62. Step 6:
1.PSC box segments are lifted one by one by lifting beam
and crab hoist
2.The segments are held hanging by vertical hangers on
sliding beams
Active
Active
Active

63. Step 7:
1.All PSC box segments are lifted and supported by hangers
2.Epoxy glue are applied on segment joints and are
temporary prestressedwith adjoining segments one by
one.

64. Step 8:
1.Prestressingtendons are inserted in sheathing and
tendons/cables are permanently prestressed
2.Hangers are detached from segments and PSC box
girder is supported on bearings
Prestressing
tendons
5

66. Elevated Metro station

67. Elevated Station
Station box: 21 m. wide & 140 m. long

68. •OPTION –3 (2019.05.28)
CROSS SECTION OF A TYPICAL ELEVATED STATION

69. LONGITUDINAL SECTION
•OPTION –(2019.07.20)

70. Cross section of a metro station

71. Concourse Level Plan

72. TYPICAL CROSS SECTION
•OPTION –1 (2019.05.28)
Cross section at location of stairs Cross section at location of Lift shaft

73. Platform Level Plan

74. THANK YOU