The National High Speed Rail Corporation Limited has completed a 100-metre-long steel bridge over an underground metro tunnel in Ahmedabad district as part of the Mumbai-Ahmedabad Bullet Train Project.
This is the 13th steel bridge completed in Gujarat, out of a total 17 steel bridges planned in the state for the high-speed rail corridor.
In Ahmedabad district, the bullet train viaduct is generally being constructed using span-by-span structures with spans ranging between 30 and 50 metres. However, at this particular location, the alignment crosses over the underground metro tunnel connecting Kalupur and Shahpur metro stations. To ensure that no load from the bullet train structure is transferred onto the metro tunnel, the foundations were kept well away from it, necessitating an increased span of approximately 100 metres.
Due to this constraint, the superstructure design was modified from a conventional span-by-span viaduct to a steel truss bridge, ensuring structural safety for both the bullet train corridor and the existing metro infrastructure.
The bridge was assembled at a height of 16.5 metres above ground level on temporary trestles at the site. After the assembly was completed, the temporary supports were carefully dismantled, and the structure was lowered and placed precisely on its permanent support system to maintain safety and structural accuracy.
Weighing 1,098 metric tons, the steel bridge is located parallel to the Ahmedabad Sabarmati main line of Western Railways. The structure measures 14 metres in height and 15.5 metres in width. It was fabricated at a workshop in Wardha, Maharashtra, and transported to the site using trailers.
To facilitate on-site assembly, a temporary platform measuring 11.5 metres by 100 metres was constructed. The bridge has been built using approximately 45,186 Tor-Shear Type High Strength bolts, and features C5 system protective painting along with elastomeric bearings to enhance long-term durability.
