GUWAHATI, Sept 11 - Work is progressing as per schedule at Bridge No. 164 on the new Jiribam-Imphal broad-gauge line in Manipur, which will be the world�s tallest rail girder bridge when completed. Officials at the Northeast Frontier Railway (NFR) Construction Organisation said the Rs 450-crore bridge would be ready by June 2019.
�Once completed, the Bridge No. 164, across the valley of the Ijai river near Noney, will be the world�s tallest rail girder bridge. It will have a pier height of 141 metres. It will thus surpass the existing record of 139 metres of the Mala-Rijeka viaduct at Montenegro in south-eastern Europe,� SK Ojah, Senior Public Relations Officer (SPRO) of the NFR (Construction), told The Assam Tribune.
He added, �Progress of work has been good so far. More than 50 per cent of work on the bridge is complete.� The new broad-gauge line from Jiribam to Imphal in Manipur, which has been declared a national project, is scheduled for completion by 2020 and will serve as a vital link in the proposed Trans Asian Rail Network.
The entire engineering of Bridge No. 164 � right from conceptualisation to detailed design and construction � has been done indigenously by the NFR (Construction). The length of the bridge will be 703 metres.
Ojah said that large-diameter RCC circular piles are being used for constructing the foundation of the bridge, while RCC circular hollow columns are being used for the piers and open-web steel girders of 106.5 metre span have been used for the superstructure.
�The material requirements for the bridge include 65,000 cubic metres of concrete, 12,000 tonnes of reinforced steel and 600 tonnes of high tensile steel for girders to add greater strength and resistance to dynamic forces caused by moving trains. Materials are being transported from different parts of the country as they are not locally available. While piers are being driven by using hydraulic augers, the self-erecting electric lifts at each pier will facilitate safe and speedy conveyance of men and materials to the top,� he said.
A laboratory at the site has been established to test and pass all the materials that are being used in the bridge construction. Experts from outside are also consulted for double-checking the quality control system.
�Once completed, the health and in-service performance of the bridge are proposed to be monitored by using sensors at critical locations. The sensors will also record climatic features like wind speed,� said the NFR (Construction) official.
The new railway line cuts across the lower Himalayan ranges, necessitating construction of a series of tunnels through the hills and tall bridges across the deep valleys.
�Besides being located in a seismically active zone, the area is also marked by very high wind speeds and heavy rainfall for much of the year. The general soil profile is shale, which is not suitable for a bridge of this magnitude. The biggest challenge is to ensure sustainability of the bridge against hostile weather conditions. It needs adoption of state-of-the-art design, and construction and maintenance techniques. Site-specific earthquake studies, detailed model studies and wind tunnel analysis were performed to ensure a safe, economical and sustainable design,� Ojah pointed out.