Delhi Metro Constructs bridge with 100 metre long Span at Okhla Over Indian Railways Tracks
The Delhi Metro has constructed a bridge with
a hundred metre long span at Okhla over the Indian Railways tracks on the Central
Secretariat – Badarpur corridor. The bridge is a major engineering landmark as
it has been constructed without hampering the railway traffic below.
The main details of this bridge are:
- This is the
longest span ever built by the DMRC. Earlier, the Delhi Metro had
constructed a bridge over the Indian Railways lines near Pragati Maidan,
where the length of the main span was 93 metres.
- The DMRC had to
use such a long span over the Northern Railways track as four Indian
Railways lines are passing below the bridge. The bridge, which is located
between the Okhla and Jasola Metro stations, has a total length of 250
metres and is divided into three spans. While the middle span is of 100
metres, the other two spans on the sides are of 75 metres each.
- The Delhi Metro
has employed the ‘Balanced Cantilever Construction methodology (BCLC)’ for
its construction so that the rail traffic below the Metro corridor is not
hampered. This technique employs the use of a bridge builder that
constructs the bridge segment by segment at a time.
- This bridge has
been built using M-60 grade concrete and about 130 workers were engaged in
the construction of the bridge on a daily basis.
- The construction
of this bridge was difficult since the bridge was built on a very sharp
curve with a 300 metre radius and the installation of the individual
segments of the bridge on the curve was difficult as the rail traffic
moving below could not be obstructed during the construction.
- The heavy works
such as gantry movement were done under traffic blocks on railway tracks.
Since the bridge balance was always in a see-saw condition, engineers had
to maintain strict construction sequence. Additional temporary supports
were designed for added safety.
Engineers monitored the stresses and strains in these temporary
supports as well as inclination and tilt in the super structure of the
bridge at every stage of construction.
electronic indicators were also installed with the help of Japanese
scientists and the Japan International Cooperation Agency. Japanese consultants on DMRC works
interpreted all monitoring data regularly and kept designers in the loop.
Strict survey control and monitoring could ensure a safe construction with
- The existing
railway tracks below this bridge link New Delhi with Agra, Mathura on
Mumbai main line and then to other parts of the country and therefore is a
very important railway stretch.