Nagpur: In probably the first construction exercise of its kind for Nagpur Metro, 80 massive precast pier arms — some weighing up to 120 tonnes — will form the structural backbone of four elevated stations on the upcoming Lokmanya Nagar-Hingna corridor.A senior MahaMetro official said precast structures of such weight were not required during Phase-I. Reach-3A marks the first time the agency is handling components this heavy, and in such large numbers, along a single Metro stretch.The 6.4-km Reach-3A corridor, part of Nagpur Metro Phase-II, will have seven elevated stations. “Advanced precast technology is being used to accelerate construction while minimising prolonged on-site work and disruption to road traffic below,” the official added.Each station will use 20 giant concrete (pier) arms — 10 to support the concourse, where passengers will find ticket counters and other facilities, and 10 to support the platform above. Altogether, 80 such arms will be installed across the first four stations.An 800-tonne crane is being used to lift these huge arms and place them on both sides of the station’s central pillar. At Hingna Mount View station, all the arms needed for the concourse level are already in place, while work on the platform-level arms is underway. The same construction process has now begun at APMC station.The scale of the exercise is enormous. Some of the giant concrete arms being used to build the stations weigh as much as 120 tonnes — roughly the weight of 20 elephants — while the smaller ones weigh about 47 tonnes. Each arm takes about a week to make before being transported from MahaMetro’s Khairi casting yard to the construction site on specially designed heavy-duty trailers.Once these massive arms are lifted into place on either side of a station’s central pillar, they act like giant ‘shoulders’ that support the station. Workers then connect the two arms and place huge concrete beams, known as I-girders, across them. These girders form the main frame on which the station floors and platforms will eventually be built.Each station will need 60 such girders, each weighing between 30 and 45 tonnes. MahaMetro expects the installation of these beams, followed by construction of the station floors, to take about 45 days per station. Work is progressing simultaneously at multiple stations to keep the project on schedule.
