Winning the race against time
This day could have well gone down as one of the coldest days of 2022 in Nagpur. Instead, February 4 is very likely to be remembered as the day when an 80m double decker steel span, weighing 1650MT, was erected over live railway tracks at Reach-2 of the city’s Metro Rail project. The entire task was achieved in just two months, making it one of the fastest such activity in India’s Metro Rail construction history.
“It was a chilly, windy Friday morning,” says Project Manager Arun Kumar, adding, “The double decker Open Web Girder (OWG), which was created with 1,650MT structural steel with 8,000 structural elements, was placed over the busy Gaddigodam Railway Crossing during the extreme winter months. All the activities were done in extremely tight railway block hours, given how busy this route is. The span stands at a height of 28m above ground. Such a critical and complex task has hardly ever been attempted in India.” More than 150 trains pass the tracks daily as do over one lakh vehicles over the construction site.
Apart from the 80m steel span, two adjacent composite girders with RCC deck slab, each of 25m span, had to be completed. During the preparatory stage, the team manoeuvred the project’s technical complexity amidst space constraints at site, severe winter, unseasonal rains, the pandemic as well as a tight deadline. However, Nagpur Metro Rail Corporation Limited (NMRCL) had other plans.
With Afcons already setting a precedent with before-time delivery of complex elements at Reach-3, it was no surprise when the client asked the team to complete the activity in two months instead of the allotted five months. A crack team was formed under Executive Vice Chairman K Subramanian’s supervision and leadership, which innovatively completed the task within two months adhering to all quality and safety standards. Several records were also created in the short period.
“All forces collaborated to make this once-in-a-lifetime challenge a success with the able guidance of our EVC. Apart from our colleagues at the site and Head Office, we also enlisted expert support from the Chenab Railway Bridge Project to critically review our preparedness. Manpower and machines were mobilised at unprecedented pace,” reminisces Project Controller Amarsinh Raut. Four 250-500T cranes, one super lift arrangement, 22 torque wrench machines were deployed, and special lowering arrangements were made.
The road is now clear for what is the highlight of this project - India’s first four-layer transportation corridor. Once the double decker corridor is operational, an existing vehicular and pedestrian underpass will form the bottommost layer with the railway line over it. The National Highway will be the third layer, the Metro line the fourth. The highway layer is at a height of 22m as against a normal height of 6-7m in the country.
Given the merit of this milestone, NMRCL is considering having them featured amongst India and world records. “Constructing this unique transportation system is a dream come true for engineers. We will be humbled if this engineering activity makes the record books,” says Raut.
