The document discusses the need for mass rapid transit (MRT) systems in urban areas, highlighting the rapid urbanization and challenges faced due to increasing population and personal vehicles in India. It details the growth of metro rail systems in the country, with significant expansions and various types of metro structures such as elevated viaducts and tunnels, alongside key construction considerations. Furthermore, it outlines the types of civil engineering structures involved, including foundations, piers, and girders essential for metro rail construction.

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

2. Need for Mass Rapid Transit
System

3. Need for Mass Rapid Transport (MRT) System
 Today, about some 56% of the world’s population (Total population 8.0 billion) i.e.
about 4.5 billion inhabitants live in cities. This trend is expected to continue, with the
urban population more than doubling its current size by 2050 (70% of total
population).

4. Need for Mass Rapid Transport (MRT) System
 There is no universal definition of what constitutes an ‘urban area’; definition vary widely across
countries, both in terms of the metrics used to define them, and their threshold level.
 The data of shown for a given country in the map on previous slide is its nationally-defined minimum
threshold. 2000 and 5000 inhabitants are the most frequently used threshold level (by 23 countries
each). However, these ranges vary widely. 133 countries do not use a minimum settlement
population threshold in their ‘urban’ definition. Some use a variation of population density,
infrastructure development, or in some cases no clear definition.

5. Need for Mass Rapid Transport (MRT) System
 By 2030, the world is projected to have 43 megacities with more than 10 million
inhabitants, most of them in developing regions. However, some of the fastest-growing
urban agglomerations are cities with fewer than 1 million inhabitants, many of them
located in Asia and Africa.
 However, the speed and scale of urbanization brings challenges, such as meeting
accelerated demand for affordable housing, viable infrastructure including transport
systems, basic services, and jobs.

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. 25 km
248 km
Growth of Metro Rail…
First modern energy efficient ACmetro
services started in Delhi; 8 km stretch
between Shahdra and TisHazari
1984
First metro service started in Kolkata -
a small section of 3.4 km underground
metro network; 12 years toconstruct
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
Major thrust through Policy, Planning, Options, Financing, Innovations and
‘Make in India’
2014
Growth of Operational Metro Network in thecountry
2021
5
0 km
1 city 2 cities 5 cities 18 cities 27 cities
Item Before 2014 Addition after 2014 Current Status
No. of cities with operational Metro Network 5 13 18
1,70
Commissioning of new metro rail lines (km) 248 454 702 733 km
Approved metro networks, including RRTS for construction(km) 659 1,059 1,718 operational
metro network
Approved RRTS corridor for construction (km) 0 82 82 202
Metro passengers per day (ridership in lakh) 17 68 85
(pre-Covid19)

8. Metro Rail Spread
Under Construction Operational
Bhopal
Indore
Patna
Agra
Delhi & NCR
(8 cities)
Ahmedabad/
Gandhinagar
Surat
Mumbai, Thane &
Navi Mumbai
Pune
Bengaluru
Jaipur
Kochi
Chennai
Hyderabad
Nagpur
Kolkata
Lucknow
Kanpur
Meerut
RRTS
Metro Rail 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 continuous fencing
/ Kerb separating 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
tyred coaches 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
≤ 10000 5-6 Km.
Rail
Rapid
Mass
Transit
System
Mono
Rail
Monorail trains
(electrically propelled
rubber tyred rolling
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 LRT
LRT 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
metres and each coach weighs 15 tonnes.
Maximum Operational speed: 80 Kmph.

15. Mono Rail System

16. Skybus Metro 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. Skybus Metro System

18. Skybus Metro 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
 Metro lines are mostly constructed in congested urban areas.
 Since metro line is constructed in urban areas, major challenges in its
construction are:
(1) Constraints in construction due to limited working space (in congested
urban area), limited working hours for transportation of materials to & from
site (during night time only) and for actual construction activities (during
day time only).
(2) Dealing with large number of sub-surface, surface and overhead public
utility services, viz. sewers, water mains, storm water drains, gas pipe lines,
telephone cables, electrical transmission lines, electric poles, traffic signals
etc. falling in metro alignment:- Either redesign of metro structures or
shifting utility/supporting & maintaining them during construction.
(3) Regulation of vehicular traffic during construction.

22. Civil Engineering Structures in
Metro rail System

23. Civil Engineering Structures in Metro rail
From construction point of view, metro Civil Engineering
Structures can be broadly classified in to:
(A) Elevated
(i) Viaduct
(ii) Station
(B) Underground
(i) Tunnel
(ii) Station
(C) Maintenance depot

24. Elevated Viaduct

26. Pile Foundation

27. Construction of Pile foundation
• Generally, in metro rail construction bored cast in situ R.C.C. pile
foundation of 0.8 m, 1.00 m & 1.20 m diameter with varying depth (22 m.
to 32 m.), depending upon foundation soil properties, are used.

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
• Metro piers are generally cast-in-situ Reinforced Cement Concrete
(RCC) structure. They are generally circular, oblong, square or
rectangular in shape.

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
• Pier cap is either cast-in-situ RCC or precast post tensioned Prestressed
Concrete (PSC) structure. But now, mostly precast post tensioned
Prestressed Concrete (PSC) is used for both pier cap (viaduct) and pier arm
(stations).
Cast-in-situ Pier cap construction

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

36. Bearings

37. Bearings
• A bridge bearing is an element of superstructure which provides an interface between the
superstructure and substructure.
• Bearing performs the function of
(1) allowing translation and rotational movement of superstructure to occur and
(2) transfers the entire load from superstructure to the substructure of bridge.
• Types of bearings in Metro rail:
1. Elastomeric bearing: An Elastomer is a polymeric substance obtained by vulcanization of rubber.
Elastomeric bearing consists of elastomer layers with 1 mm to 3 mm thick steel plates between the
elastomer layers bonding firmly with the elastomer. Used for bridge span up to 45.7 m.

38. Bearings (Contd.)
2. POT-PTFE bearing: Used for relatively larger span/heavier load. PTFE (Poly Tetra Fluoro
Ethylene), also known as Teflon, is a hard & durable material and it possesses high
chemical resistance. The elastomer pad inside the POT provides rotational movement by
differential compression of elastomer. The translation movement to superstructure is movement
is provided by steel plate sliding over PTFE. The coefficient of friction between PTFE and stainless
steel is the lowest between any two materials within the normal temperature range.

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.
Spherical bearing is provided in Metro railway bridges with spans
of 61 m. or more or in open web through girders where high
rotational & sliding movement are needed and the vertical
load transmitted through each bearing is too large.

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 site and
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 manoeuvring of
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
Active
Active 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
Active
Active

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 prestressed with adjoining segments one by
one.

64. Step 8:
1. Prestressing tendons 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