‘Infrastructural marvel’: World’s highest railway bridge in J&K is simply breathtaking
Introduction and topograph
The Chenab Bridge is an Indian railway steel and concrete arch bridge between Bakkal and Kauri in the Reasi district of Jammu and Kashmir, India. The bridge will span the Chenab River at a height of 359 m (1,178 ft) above the river, making it the world’s highest rail bridge.
Northern Railway has undertaken the mega-project of constructing a new railway line across the Indian union territory of Jammu and Kashmir between the towns of Udhampur near Jammu and Baramulla on the north western edge of the Kashmir Valley. This project was declared a national project in 2002. It is directed by the Northern Railway. In April 2021: Both the end of the arch touched and closed on 5 April 2021. Suspecting the bridge to be opened in 2022
The extraordinary challenge lies in a large number of tunnels (totalling 63 km in length) and bridges (7.5 km) to be implemented in highly rugged and mountainous terrain, with the difficult Himalayan geology. The most difficult part is believed to be the crossing of the deep gorge of the Chenab River, near Salal Hydro Power Dam by the Chenab Bridge.
Key feature :
- The world’s highest railway bridge
- The bridge with the longest span in the Indian broad gaugerailway network.
Key technical data of the bridge:
Deck height (height above river bed): 359 m (1,178 ft), (height above river surface): 322 m (1,056 ft)
Bridge length: 1,315 m (4,314 ft), including the 650 m (2,130 ft) long viaduct on the northern side
Arch span: 467 m (1,532 ft)
Arch length: 480 m (1,570 ft)
The Chenab Bridge was designed as a large span single arch steel bridge with approach viaducts on either side.
The arch is two-ribbed, fabricated from large steel trusses.
The chords of the trusses are sealed steel boxes, internally stiffened and filled with concrete to assist in controlling wind-induced forces on the bridge. Another advantage of concrete filling is that internal painting will not be required.
The number of bearings has been minimized, particularly on the approach viaduct, through the use of continuous construction. This is advantageous, as it reduces the maintenance and inspection efforts, and improves the riding quality.
The viaduct piers are of concrete, while the piers near the arch are steel.
The design of major arch rail bridges requires considerations of a number of additional parameters, such as fatigue, global stability, second order effects, composite action, etc.
It also requires that such a bridge is designed to achieve a consistent level of reliability for all load cases, and that the design standards match the construction standards. Indian construction standards such as the Indian Railway Standards (IRS), the Indian Road Congress (IRC) and the Indian Standards (IS) were found inadequate for the large spans of the Chenab Bridge.
Following are some of the design considerations taken into account:
The bridge is designed to withstand high wind speed of up to 266 kmph and earthquake forces of highest intensity
“Approximately 584 kilometers of welding was done to join the different parts of structure, which is to the tune of distance between Jammu Tawi to New Delhi,”
“This bridge is 1,315-metre long and is the highest railway bridge in the world being 359 metres above the river bed level. It will be 35 meters higher than the iconic Eiffel Tower in Paris (France),”
The sophisticated Tekla’ software has been used for structural detailing and the structural steel is suitable for -10 degrees Celsius to 40 degrees Celsius.
The 1.3-kilometre-long bridge aims to boost connectivity to the Kashmir Valley and it is being constructed at a cost of Rs 1,486 crore as part of the Udhampur-Srinagar-Baramulla Railway Link (USBRL) project.
Construction of the bridge involves fabrication of 28,660 metric tonnes of steel, 10 lakh cubic metres earthwork and 66,000 cubic metres of concrete.
Overall weight of the arch is 10,619 metric tonnes and “the erection of members of the arch by overhead cable cranes was done for the first time by the Indian Railways”.
Blast resistant design used.
Talking about safety measures, Gangal said the bridge was designed for blast load in consultation with the Defence Research and Development Organisation. This is the first such design in the country and it can remain operational at a restricted speed of 30 kmph after removal of one pier or trestle