Chenab Bridge

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Chenab Bridge
Chenab railway bridge 7770b (9288239078).jpg
Coordinates33°9′3″N 74°52′59″E / 33.15083°N 74.88306°E / 33.15083; 74.88306
CarriesIndian Railways
CrossesChenab River between Bakkal and Kauri.
Characteristics
DesignArch Bridge
MaterialSteel and Concrete
Total length1,315 m (4,314 ft)[1]
Height(river bed to formation) 359 m (1,178 ft)[1]
Longest span467 m (1,532 ft)
No. of spans17
Jammu–Baramulla line
338Baramulla
to Kupwara (planned)
330Sopore
323Hamre
315Pattan
307Mazhom
292Budgam
Srinagar–Kargil–Leh line (planned)
281Srinagar
275Pampore
Jhelum Bridge
269Kakapora
259Awantipora
252Panchgam
245Bijbehara
to Pahalgam (planned)
238Anantnag
231Sadura
226Qazigund
218Hillar Shahabad
Pir Panjal Railway Tunnel
(11 kilometres (6.8 mi))
208Banihal
Charil
Repora
Laole
Kohli
Sangaldan Tunnel
(7 kilometres (4.3 mi))
Sangaldan
Baralla
Surukot
Bakkal
Chenab Bridge
Salal
Anji Khad Bridge
Reasi
78Shri Mata Vaishno Devi Katra
53Udhampur
44Ramnagar
Tawi Bridge
22Manwal
14Sangar
10Bajalta
to Poonch (planned)
BSicon BAHN.svg 0Jammu Tawi
To Jalandhar–Jammu line

[2]The Chenab Bridge is a railway steel and concrete arch bridge under construction between Bakkal and Kauri in the Reasi district of Jammu and Kashmir in India. When finished, 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.[3] In November 2017 the base supports were declared completed allowing for the start of the construction of the main arch[4]. The bridge is scheduled to open in 2019 though that seems highly optimisitic.[5]

Key technical data of the bridge include:[6]

  • Deck height (height above river): 359 m (1,178 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)[7]
  • Arch length: 480 m (1,570 ft)[8]

This makes the Chenab Bridge:

Introduction and topography[edit]

Chenab Bridge construction

Northern Railway has undertaken the mega-project of constructing a new railway line across the Indian state of Jammu and Kashmir between the towns of Udhampur near Jammu and Baramulla on the northwestern edge of the Kashmir Valley. This project has been declared a national project in 2002.[9] It is directed by the Northern Railway.

The extraordinary challenge lies in a large number of tunnels (totalling 63 km in length[10]) 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,[11] by the Chenab Bridge.

Another, smaller, arch bridge proposed in the new railway line was 657 m (2,156 ft) long, 189 m (620 ft) high Anji Khad Bridge between Katra and Reasi over the Raavi river. This proposal has been abandoned by the railways due to the specific geology of the location and a cable-stayed bridge is proposed.

Design[edit]

After many deliberations, taking into account aesthetics, economy, and availability of local expertise and construction materials, 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 of 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. For example, the Indian Railway Standards (IRS) is primarily intended for simply supported bridges with spans up to 100m (although these have been successfully used for higher spans up to 154m). The spans for the Chenab Bridge greatly exceed this limit, and are continuous. Therefore, to assure a safe design, Indian national standards have been supplemented with International standards such as British Standards (BS), International Union of Railways (UIC) and Euro. Also, many experts throughout the globe, based on their versatile and relevant experience, have been involved in order to make the building project a success.

Following are some of the design considerations taken into account:

  • Limit state philosophy of design has been decided to be followed as per BS codes
  • Computation of wind load effects as per wind tunnel tests
  • Site specific seismic spectra developed by Indian Institute of Technology (IIT) Roorkee
  • Provision of Euro code 8 for ductility detailing of very tall and hollow rectangular RCC piers
  • Provision of long welded rail (LWR) over the bridges and resulting force calculation as per UIC – 774-3R guidelines
  • Blast resistant design has been used
  • Design checking for fatigue as per BS codes
  • Deformation limits as per comfort criteria of UIC – 776-2R and UIC 776 -3R guidelines
  • Redundancy provided in the structures, for lower level of operation during mishaps and against collapse in extreme cases of one pier failure

The Quality aspect has been emphasized, as the quantum of fabrication and welding is colossal. Mostly indigenous material compliant to IS codes has been planned to be used, whereas for the design, international codes have been referred, which means the Quality Control work is still difficult.

Construction[edit]

The Chenab Bridge was originally intended to be completed in December 2009.[12] However, in September 2008 the project was halted due to fears over the bridge's stability and safety.[13]

Work on the bridge restarted in 2010[14] with the plan to complete it in 2015.[15]

The construction has been given to Afcons Infrastructure Limited,[16] a part of the Shapoorji Pallonji Group, the third-largest construction group in India.

The erection scheme for the bridge is a project in itself. Two pylons (about 130 m and 100 m high) were erected on either side of the river, and two auxiliary self-propelled cable cranes (capacity of 80t each) were used to tow temporary auxiliary ropes across these pylons. The ropes were used to support the partly finished arch parts. After arch completion, the trusses will be added, finally the girder will be constructed as a horizontal sliding type platform.

  • Nov 2017:The Work On Arch Bridge To Completed By May 2019.[2]

Maintenance[edit]

Regular painting of such bridges is an intimidating task; hence, a painting scheme has been developed, having life over 15 years, compared to approx. 5 to 7 years of life in most of the Indian railway bridges.

References[edit]

[17]

  1. ^ a b "Salient Features of the Chenab and Anji Khad Bridges" (PDF). Official Webpage of the Konkan Railway Corporation Limited. Archived from the original (PDF) on 2003-12-08. Retrieved 2008-08-14.
  2. ^ a b "Worlds Tallest Railway Bridge On Chenab To Complete By May 2019".
  3. ^ "World's highest rail bridge to come up across Chenab river". Hindustan Times. 2013-02-17. Archived from the original on 2013-02-17. Retrieved 2013-02-17.
  4. ^ "Railways launches main arch of Chenab: World's highest rail bridge an impressive feat but are celebrations misplaced? - Firstpost". www.firstpost.com.
  5. ^ "World's highest rail bridge taller than Eiffel Tower on Chenab to be completed in two years". The Economic Times. Retrieved 4 May 2017.
  6. ^ Narayan, Laxmi (March 2006). "TECHNICAL PAPER ON ANJI KHAD AND CHENAB BRIDGES" (pdf). Advances in Bridge Engineering: 101–114. Retrieved 2008-01-14.[dead link]
  7. ^ "Chenab Bridge". Trimble Solutions Corporation. 25 June 2016.
  8. ^ "Indian Railways makes history;Awards largest bridge contract in J&K". Project Monitor. Archived from the original on 2008-02-20. Retrieved 2008-08-14.
  9. ^ "J&K Rail Link Project". Northern Railway Website: Official Page on the Kashmir Railway Project. Archived from the original on 6 May 2008. Retrieved 2008-05-08.
  10. ^ "At 359 metres, rail bridge over Chenab will be world's highest". Times of India. Retrieved 2011-05-31.
  11. ^ "Chenab bridge will be highest in the world". Online edition of The Hindu, dated 2008-01-17. Chennai, India. 2008-01-17. Retrieved 2008-08-14.
  12. ^ "J&K to have world's tallest bridge". TOI News. 2007-11-05. Retrieved 2008-01-14.
  13. ^ Reasons for cancellation, reinstatement against security concerns
  14. ^ "Work Resumes on Tallest Rail Bridge in India - Railway Technology". 10 June 2010.
  15. ^ "Highest railway bridge in J&K to be ready by 2015". The Times Of India. 18 June 2012.
  16. ^ "India joins the superlative club, we now have the world's highest rail bridge". India Today. Retrieved 2013-07-04.
  17. ^ Tiwari, Neelam. "World Tallest Railway Bridge, Being Built Over Chenab In Jammu and Kashmir ", Dainik Bhaskar,3 May 2017

External links[edit]