Delhi Metro on Sunday commenced trial runs on the fully elevated 14 km-long Badarpur-Faridabad corridor, setting in motion the process of formally opening the line by June.
Specially Designed Beams Fast-track Badarpur-Faridabad line
The Badarpur-Faridabad corridor of Delhi Metro, set to be made commercially operational by June 2015 has come up at a record pace as specially-designed beams were used in building the viaducts of the fully elevated line. Officers in-charge of the project explained that the use of U-shaped support beams or U-girders, which can measure up to 27 metre, helped in fast-tracking the construction work of the 14 km-long corridor.
“Single segment of a viaduct can be built using only two spans of U-girders whereas several spans of normal girders would be required in building the same span as they have a length of not more than 2.5 metre,” an official said, adding that the technology was used at the Airport Express Line also, however, by a foreign contractor.
To further expedite the construction process, Metro also used precast girders, which could be brought to the sites and installed in a short span of time, even in a single day. Preliminary work for the corridor started in February 2012. Trial runs on the same commenced on Sunday, the official said. In contrast, another official said that it takes at least five days in building a segment through the conventional method. “Through engaging more labourers it can be done in three days,” the official said.
Moreover, portals were generally constructed on site due to their long size and heavy weight. But the plan had to be shelved due to possibilities of hampering traffic on NH-2 for at least six months. “Therefore, for the first time in DMRC’s history, the decision to install precast portal beams was taken. These portal beams were cast at the casting yard and brought on site for installation,” a spokesman said.
Giant 400-500-tonne cranes were employed to carry the girders to the construction sites from the casting yard. Metro faced further challenges on building certain alignments of the corridor, especially where the line moves to the left side of the highway from the right near the Badarpur toll plaza towards NHPC Chowk. “On this stretch, the alignment curves about five times on a 300 metre length. To take the alignment through these curves, six portals and five extended pier caps were also used for the first time on which the tracks rest,” a Metro official said.