BrIM chasing new highs in India - Chenab Bridge

Yong Wei Tee

Chenab Bridge is part of the new Baramulla—Srinagar—Udhamptur railway in northern India, crossing the river Chenab in the Kashmir valley. It is one of the tallest and longest-spanning railway bridges of its kind in the world.

Tekla Structures has been in use from the beginning of the ongoing project, which has greatly benefitted from the software; all structures, temporary cables and related anchoring towers have been designed using Building Information Modeling (BIM). BIM has also been utilized on site for erection sequence planning, geometry and quality control, and the workshop drawings and CNC data are sourced directly from the model. The contractor employs the models in close co-operation with the designer, and the third-party inspector has made use of it in the reviewing process

Getting people on the move

The measures of the finished bridge are impressive: it is constructed 320 meters above the surface of the river Chenab, and it stretches to a total length of 1,315 meters. The main arch of the Chenab Bridge spans a spectacular 467 meters, making it one of the longest arch railway bridges in the world, and the deck, designed for two rail tracks, is 13.5 meters wide.

Erected on Himalayan bedrock with foundations approximately 40 meters high and 50 meters wide, the arch and piers of the bridge are masses of steel trusses, while the foundations and the approach viaduct piers are made of concrete. The arch is erected with a cableway crane, after which the deck is then launched into placed and joints assembled with a total of 600,000 bolts.

The Kashmir valley is one of the most isolated regions in India, and the mountainous and rough Himalayan terrain lacks a proper road network. The railway, and Chenab Bridge as part of it, is expected to remarkably affect the development of the region, improving accessibility and transportation for the local population. As one of the highest and largest railway bridges in the world, the bridge is also expected to become a popular tourist attraction, with footpaths and cycle trails to be built alongside it.

Tekla Structures from start to finish (and maintenance)

The bridge owner, Konkan Railways Corporation, set specific standards that had to be followed in the design process. Indian Railway Standards had to be applied wherever possible, and British Standards, UIC Standards and other international standards could be used as a supplement.

Using 3D modelling was a prerequisite set by Konkan Railways Corporation. WSP Finland, the designing consultant of the project, chose Tekla Structures, which allowed the company to organize the plate material for better logistics in the difficult terrain and made it easier to receive the approval of local authorities, as visualized 3D models are more practical to present than 2D drawings. WSP Finland used the software to increase efficiency and optimization with its extensive range of connections and automated clash checking, which exposes conflicts at an early stage. Tekla Structures also enabled WSP Finland to execute reinforced concrete, braces, elements and block constructions, and due to its dimensional accuracy and steady coordinates, the end result was reliable and as expected. The 3D model also generated reports for material quantity take-off, assembly dimensions and center of gravity for lifting and transportation. The high level of development (LOD) and accuracy of the model allowed it to be used for fabrication in the temporary workshops on site.

With Tekla Structures, users can create a constructible, parametric model, which means each object holds its own data. This data can then be used for fabrication, erection, construction on-site and asset management during the maintenance of the bridge.

“We use Tekla Structures because it is a parametric modelling tool and the model includes all of the data that is relevant to the project, from conceptual design to detailing and fabrication,” says Matti-Esko Järvenpää, Development Manager, Bridges & Structures at WSP Finland. “The accurate data can be used in construction on-site, and even for asset management later in the maintenance phase.”

BIM boosting workflow

The design practices in bridge projects have gradually moved towards model-based design, where data is exchanged between parties on the model. Visualizing information makes it easy for parties to understand the process, and in the planning period the components can be associated with scheduling information. This information can be utilized in visualizing the construction and planning by using the quantity management and scheduling properties of the modelling software. These components include important information that can be taken advantage of in the implementation phase.

Throughout the process, BIM has proven its capabilities in various ways. Using BIM and Tekla Structures software on the Chenab Bridge has made assessing information at every stage of the design project possible, while improving efficiency and productivity, and minimizing the need for rework. By boosting the level of collaboration, BIM smoothens workflow.

Header image used courtesy of WSP Consulting/Kortes Ltd/Leonhart, Andra and Partner

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