This document provides information about industrial training on construction of a metro station. It discusses the cut-and-cover construction technique used to construct underground metro stations. It also describes the top-down and bottom-up construction methods for cut-and-cover tunnels. Bearings are discussed, including their functions, types of bearings like elastomeric bearings, and design of bearings according to code. The tendering process and types of tenders are summarized. Concrete mix design and grades of concrete are also outlined.

1. INDUSTRIAL TRAINING ON CONSTRUCTION IN METRO
UNDER SUPERVISION OF
MR. PRASHANT KUMAR
A.M-CIVIL/TRACK(NMRC)
UNIVERSITY SCHOOL OF ENGINEERING
GAUTAM BUDDHA UNIVERSITY
GREATER NOIDA
PRESENTED BY
AJINKYA RAJ
20/BCE/026

2. Introduction
A metro station is a railway station for a rapid transit system, which as a whole is usually called a
metro or subway.
A station provides a means for passengers to purchase tickets, board train, and evacuate the
system in the case of an emergency.
Most stations are located underground, with entrances/exits leading up to ground or street
level.
In other cases, a station may be elevated above a road, or at ground level depending on the level
of the train tracks.

3. Metro Station Construction
Construction of the underground stations would employ the cut-and-cover construction technique
generally begins by opening the ground surface to an adequate depth to permit support of existing
utility lines and to install soldier piles, or other earth retaining structures. The surface opening is then
covered with a temporary street decking so traffic and pedestrian movement can continue overhead
while excavation proceeds beneath the decking.

4. CUT AND COVER CONSTRUCTION
METHODOLOGY
The cut and cover method is suitable for construction of
station box and cut and cover tunnel in soft for mixed ground
conditions especially for excavation with shallow depth (less
than 30m).
There are two basic cut and cover construction methods,
namely Top down and Bottom up.
Both methods are suitable for station box construction, while
tunnel box structure is usually constructed by bottom up
method.
The system basically comprises of retaining walls and
strutting system.

5. TOP DOWN CONSTRUCTION METHOD
•In the top-down method, the permanent station structure walls are built
along the excavation boundary from top to bottom.
•The walling system, usually in the form of a diaphragm wall, is first installed
and then excavation is carried out up to roof slab level.
•After casting the roof slab, the excavation is continued up to the next level
of slab. This process is repeated until the excavation reaches the base slab
level.
The retaining walls shall usually be used as part of the permanent station
walls. The strutting system is usually the slabs of station structure
themselves and may occasionally be with some temporary steel struts,
depending upon the site specific requirements.

8. BOTTOM UP CONSTRUCTION METHODLOGY
•In the bottom up method, the retaining wall is constructed along the station
or tunnel boundary prior to excavation.
•Excavation is carried out to a certain depth and then a strutting system is
installed to support the retaining walls during excavation and construction
of the station.
•After the installation of the strutting system is completed and the final
formation level is reached, the base slab is cast in accordance with normal
procedure.
The wall can either be temporary or part of permanent structure. The
strutting system is removed after casting the slab.

12. What is Bearing?
The bearings transfer the forces coming from superstructure of a bridge to the
substructure. These also allow necessary movements in the super- structure
which are caused by various reasons like temperature variations.

13. Functions performed by Bearing
Transfer of vertical loads
Allowing rotation of Girders: The girders deflect under vertical loads which is
maximum in the middle. This causes rotations at the ends near supports.
Bearing facilitate this rotation.
Transfer of Lateral & Longitudinal loads: Loads such as Seismic/ Centrifugal/
wind etc are transferred to the substructure
Allowing certain movements: The girder expands/ contracts under thermal
variations. Bearings allow movements arising due to this thermal variations.

14. Elastomeric Bearings
• Elastomeric Bearings consist of synthetic rubber layers reinforced with steel layers in
between which provide the sliding as well as rotation capabilities.
• These bearings have no moving parts and require least maintenance.
• There is no arrangement to prevent lateral movements or to provide fixed end in these
bearings. Separate arrangements have to be made if such a requirement is there.
• Bearings are very stiff in resisting volume change but are very flexible when subjected to
shear or pure uni-axial tension.
• They are generally reinforced with a steel plates in alternative layers to reduce bulging.

15. Design of bearing
As per IRC 83:2015 (part ll)
• Depending upon the plate thickness, the bearing has been classified from type A to I. In our
project, Type B bearing with uniform thickness is used.
• Minimum thickness of top and bottom cover 2.5 mm
• Minimum thickness of side cover 4 mm
• All internal layer shall be of uniform thickness and between range of 8mm to 20mm
• Minimum thickness of steel plate is 3mm

16. Tendering
The tender is an offer to perform some task or to supply goods at a fixed price.
The contractors will be invited to submit sealed bids for construction or for the
provision of specifically designed services or goods during a particular time
frame in the initial step of this tender process.

17. Types of Tender
1. Open Tender: An open tender is the principal tender procedure employed by both
the private and government sectors. In the local newspaper, the customer advertises
the tender offer along with the key information of the proposed works and invites
interested contractors.
2. Selective Tender: Selective tendering is an alternative that has been developed to
address the open tender procedure's limitation. This tender aims to increase the quality
of bids received and ensures that contractors with the requisite expertise are given the
opportunity and submit the bids needed.
3. Negotiation Tender: This is widely used in the engineering and construction industry,
which is the subject of pre-contract and post-contract negotiations.

18. Concrete Mix Design
Concrete is a composite mixture which consists of Cement, Sand and Aggregate. Concrete
mix design is the procedure for finding the right quantities of these materials to achieve the
desired strength. Accurate concrete mix design makes concrete construction
economical. Large constructions such as Bridges, dams requires huge amount of concrete,
using the right quantity of constituents make the structure economical. In order to calculate
or find the right amount of cement, sand and aggregate required in 1m3 of concrete; you
need to know about different grades of concrete.
As per IS456:2000, Different grades of concrete are classified into M5, M7.5, M10, M15 etc.,
whereas M stands for Mix and the number behind M stands for Characteristic Compressive
strength (fck) of the concrete in N/mm2 @28 days when checked with
15cm×15cm×15cm cube in direct compression test.
Mix Design (M) = Cement: Sand :Aggregate

19. Different grades of concrete
Different grades of concrete has different
Concrete Mix proportions which means
different concrete mix ratios. As
Per IS456:2000, the Concrete mix design has
the following concrete mix proportions :

20. THANK YOU