Chenab Bridge

The Chenab Bridge is located in the Jammu and Kashmir area, approximately 600 km North of New Delhi. It is part of the new Baramulla−Srinagar−Udhamptur railway connection.

The total length of the bridge is 1315 m. The free span length of the bridge is 467 m measured from the surface of the river below, the height of the bridge deck is 350 m. Thus, the Chenab Bridge is the tallest and longest-spanning railway bridge of its type in the world. Because it is located in an extremely demanding mountainous area with modest roads and infrastructure, the construction of the bridge has been extremely challenging.

The end result is a convincing demonstration of WSP's world-class steel bridge design expertise. The project was carried out on a "design and build" contract model. The contractor and client required the use of BIM modelling of the structures from the very beginning of the project. All steel structures were modelled using Tekla software, which ensures the compatibility of the steel components during installation. All steel structures were modelled. The total steel volume of the bridge is 27 000 tons. The design of the bridge was also challenged by the demanding earthquake and wind conditions. The bridge design team was led by Pekka Pulkkinen from WSP in Finland.

The WSP-led team designed the bridge and its steel structures using information modelling. A considerable amount of detailed steel structures drawings were produced.

• The arch bridge is made of steel. The foundations and the piers of the inlet bridge section are of concrete construction. The arch section was installed in place using a cable crane and the deck was pushed into place. All the installation joints are practically bolted joints, with a total of about 600 000 bolts. The bridge is founded on rock. The foundation of the arch span is about 40 m high and about 50 m wide.
  
  
• All bridge structures are accurately 3D modelled and the model of the steel structures even included correct welding grooves. The steel structure fabrication drawings were printed directly from the information model.
  
  
• The temporary ropes and their anchorage towers used in the outrigger installation of the arch have also been modelled. The designers had to take into account the demanding earthquake load and the potential explosive load on the structures. The data model of the structure has been implemented in a pre-stressed form.

The main challenge in wind engineering was not the size of the bridge itself but the site and altitude at which it is located. In extremely rough topographies, standard models of wind and turbulence are unlikely to be realistic; a special type of wind tunnel testing was therefore conducted to assess the design wind parameters. Wind engineering of the bridge was conducted by combining in-house wind engineering expertise and the wind tunnel tests of FORCE Technology in Denmark.

Thanks to truss structures in the arch and the piers, the bridge is not sensitive to aeroelastic instabilities, but the lateral wind load itself was of main interest. This was due to the need to control lateral displacement of the deck for smooth railway operations.

The structure must also withstand major storms. Continuous surveillance of wind conditions and a warning system will help manage rail traffic. 

Additional information:

• Interview made during the construction of the bridge: Chenab Bridge: Connecting the Arch Up in the Clouds
  
  
• Full bridge overview, published in e-mosty, about the years-long project to build the Chenab Bridge, including an article by Pekka Pulkkinen, WSP in Finland
  
  
• Article published by e-BrIM about BIM modelling in the design of the Chenab bridge , by Matti-Esko Järvenpää's, WSP in Finland