Massive steel structures dot either end of the Gaddigodam Railway bridge as M/s Afcons Ltd., a leading infrastructure company, executed perfect launch of first of the 28 tonne girders as work on the much anticipated first-ever four-way transport project of the country git going. During the two-and-a-half hours of traffic block on early Monday morning, the huge cranes lifted the mega iron girders and placed them across the railway network. This was the basic lift and second similar one is scheduled later when second block will be provided by Central Railway’s Nagpur Division. The real test would come when the open web bridge would be launched across the railway bridge over a height of 11 meters above the Overhead Equipment (OHE). The lifting and launching of girders marked the start of the most complex work on the Reach-II of Nagpur Metro that stretches from Sitabuldi Inter-change till Automotive Square. In between lies the Gaddigodam railway bridge where a unique transport arrangement is envisaged wherein there would be four layers, including two roadways and one railway and one for metro.

 

The specialty of the project can be gauged from fact that final weight of the open web bridge that would be launched later would be 1800 tonne. The bridge is already casted at a factory in MIDC and would be transported in pieces through trailers and later lifted for placing it across the railway network for the final connectivity across the Gaddigodam bridge. When completed, the project would have RuB at the ground-level for light traffic, then the existing railway carriageway, above that road overbridge (RoB) that would cater to fast moving traffic and then on top, a metro viaduct. Maharashtra Metro Railway Corporation Limited (MMRCL) is executing the project in association with National Highway Authority of India (NHAI). Explaining the rationale during talk with ‘The Hitavada’ on Monday, Amarsinh Raut, Project Director, Afcons, said two pieces of girders each of them weighing 28 tonne each and spanning 30-meter-long were placed on the either end of tubular columns and put in place at the spot. The two girders were lifted separately and then binded together in a seamless operation under watchful eyes of the J K Sinha, Senior Section Engineer, of Indian Railway, who was on duty throughout the block period, said the Afcons team. The tubular columns are fitted with 16 mm liner at bottom to provide further strength for adjusting the final weight when the pre-fabricated bridge would be assembled over head.

 

Now, a similar operation is needed for placing the other two pieces that are readily assembled at the construction site. Once the girders are positioned, a composite bridge, similar to the one put up at Variety Square for metro viaduct, would be launched. A 500 tonne capacity super lift crane has been positioned on the ground for the same. He also informed that total 900 to 950 tonnes of iron and steel material was used along with reinforcement concrete cement (RCC) blocks for supporting the launch of final bridge structure. Extra safety measures are put in places as per directives of Commissioner of Railway Safety (CRS) as the girders have been affixed with FRP insulation for heightened precaution. This is special type of affixture pasted underneath the girders so that in case the OHE comes in contact, no incident would occur as same is bad conductor of heat. The same was insisted upon by CRS in case heavy wind blows during the time of launching of bridge, it would touch the overhead iron girder and therefor presence of insulation would negate any adverse effect.