By IANS,
New Delhi : The Delhi Metro Rail Corporation (DMRC) is using extra-long girders to build an elevated stretch on its new line to the Delhi airport.
The 25 metre-long girders are being used for the first time in the country. This will speed up completion of the project ahead of the 2010 Commonwealth Games.
The Airport Express Line of the Delhi Metro is 22.7 km long, of which a distance of seven kilometres is elevated – between Buddha Jayanti Park and Mahipalpur.
A total of 504 such girders will be used on this elevated stretch.
“Such girders, which are 25 metres long and weigh approximately 120 tonnes each, have been earlier used only in Shanghai and Taipei and are being used for the first time in India,” said O.P. Singh, chief project manager for the line.
Generally, 2.5 to 3-metre long girders are being used at the other Delhi Metro corridors under construction.
“These girders are being used on the Airport Express Line to expedite the construction process. The line is to be opened by October 2010,” said Anuj Dayal, chief public relations officer of the DMRC.
The use of these girders will also save up to 10 percent cost and average time by 20 percent.
While it takes up to six days to set up the smaller girders with a casting launcher, it takes 20 minutes to fix the 25-metre-long girders on pillars, according to Singh.
Two specially designed cranes are being used to fix the girders.
The girders are being cast at a yard in Mahipalpur from where they are carried by specially designed trailers. These trailers are 35 metres long and have 64 tyres.
“It is feasible to use this type of girder only in open places with less traffic where they can be transported and the site space is large – a reason why it was not used in the Metro lines in the past,” said Dayal.
The Airport Express Line is expected to revolutionize the transport scenario of the city as a trip from the New Delhi railway station to the Indira Gandhi International Airport will take only 18 to 20 minutes.
The stretch will have six stations – New Delhi Railway Station, Shivaji Stadium, Dhaula Kuan, NH 8, Airport and Dwarka Sector – 21.
“The maximum speed on this line will be 135 km per hour as opposed to current 80 km per hour,” chief project manager Singh added.
For this the thickness of the girders has been increased, the track design would also be different and reinforcement heightened.