World's highest rail bridge on Chenab in J&K to withstand 40 kg-TNT blast

The Chenab Bridge, the world's highest rail viaduct linking Kashmir Valley with the rest of the country by rail route, is designed to withstand 40 kg of TNT blast and earthquake of magnitude eight on Richter Scale, said a Konkan Railway's top engineer on Tuesday. The upcoming "next man-made wonder", being built under the direct supervision of the PMO and Railway Board, is likely to be completed by December 2021, said Chief Engineer (Coordination) R K Hegde of Konkan Railways, which is executing the project.

A national project with 100 per cent of central funding, the bridge is being built on Chenab River between Bakkal and Kauri in the Reasi district of Jammu and Kashmir. The bridge is being built under around-the-clock monitoring directly by the Prime Minister's Office and the Railway Board in New Delhi through "electronic eyes", he said. After the completion of the bridge, the Chenab Bridge will boast of having the world's highest rail bridge -- 359 metres above the river and around 35 metres taller than the Eiffel Tower. The bridge forms a crucial and the most difficult link in the 111 km-stretch between Katra and Banihal, which is part of the Udhampur-Srinagar-Baramulla rail link project, he said.

"So far, 83 per cent of the work has been completed. For the overall completion of the Chenab bridge project, the deadline is December 2021," Hedge said. Once completed, it will surpass the record of Shuibai Railway Bridge (275m-high) on Beipan river in China, Hegde told PTI at the project site. The bridge construction, which was halted in 2008 in wake of concerns over its safety and alignment, was restarted in 2010. It has already missed many deadlines in 2015, 2016, 2017 and 2019. The construction of the bridge was started in 2002 when Atal Bihari Vajpayee was the prime minister. Talking of the bridge sturdiness, Hegde said, "It can withstand high intensity blasts of up to 40 kgs of TNT and an earthquake of magnitude 8 on Richter Scale. Even after the blast, a train can run at a speed on 30 kmhp," he said.

Blasts of such intensity cannot damage any of the bridge pillars either, he added. To ensure its sturdiness, the bridge is being built with 63 mm-thick special blast-proof steel owing to Jammu and Kashmir's propensity to frequent terror attacks, he said. Even the concrete pillars of the bridge is designed to withstand explosions and painted with a special corrosion-resistant paint, which lasts for 15 years, he said. Detailing various measures to make the bridge blast proof, Hegde said, "It is for the first time that self-compacting concrete is being used for filling steel boxes and ends of plate girders."

The Konkan Railway has also set up a blast lab at the site to test steel plates' the strength to withstand blasts of up to 40 kg of TNT. "Before being used in the project, each high-grade steel plate is being tested at the project site itself for its capacity to withstand the blast load," said an engineer at the lab. "There is no compromise with quality. We have rejected a large number of steel plates being procured from SAIL and two other companies," he added. Steel plates for the bridge have been procured from the Bhilai plant of Steel Authority of India, while the girders are assembled at a fabrication workshop adjacent to the bridge. "Each girder plate is eight-metre-long and we have estimated that 161 girders will be required for the purpose," he said.

Talking of the highest-level interest in the project, an engineer said, the PMO and Railway Board directly monitor its work progress every day through "electronic eyes". "If the CCTVs goes off for one minute, we get a call from the PMO as to what is happening. They are monitoring it round the clock through electronic eyes," an engineer said. The bridge, a 1.315 km-long engineering marvel is also designed to withstand wind speeds of up to 260 km per hour.

"The railways will also install sensors on the bridge to check the wind velocity and as soon as the wind speed exceeds 90 kmph, the signal on the track will turn red, preventing train movement," the engineer said. According to the plan, a ring of aerial security will also be provided to safeguard the bridge. "An online monitoring and warning system will be installed on the bridge to protect passengers and trains in critical conditions. Footpaths and cycle trails will also be built adjacent to it," he added. The Chenab Bridge, an arched steel and concrete structure, will connect Baramulla to Jammu via Udhampur-Katra-Qazigund with a travel time of six-and-a-half hours.

Currently, it takes exactly double the time, 13 hours, to reach Jammu from Baramulla in northern Kashmir, which is 60 km from Srinagar. Talking of measures to make the bridge earthquake-proof, Konkan Railway Chairman Sanjay Gupta said a detailed, site-specific seismic analysis has been carried out by experts from the Indian Institute of Technology, Roorkee, and the Indian Institute of Sciences, Bangalore. "The most difficult phase of the project now is the construction of the section between Banihal and Katra. This is most challenging for Konkans," he added. 

Image Credits: PTI