7 days ago
Bullet train project: How a 12-storey high bridge is coming about, segment by segment, over Sabarmati River in Ahmedabad
An under-construction bridge over the Sabarmati River in Ahmedabad, which is part of the Mumbai-Ahmedabad High Speed Rail Corridor (MAHSR) or Bullet Train Project, is being built with the advanced Balance Cantilever Technique — where the superstructure is built segment by segment, without deploying support structures needed in the scaffolding style of bridges. When complete, the bridge, spanning 480 metres, will be 36-metre-high from the riverbed — equivalent to a 12-storey building.
Located adjacent to the Western Railway's Ahmedabad-Delhi main line, which is about 14.8 meter high, the Sabarmati Bridge on the Bullet Train corridor will stand on a total of eight circular piers, four of which will be located in the riverbed.
The National High Speed Rail Corporation Limited (NHSRCL) on Friday said, 'A total of eight circular piers with diameters of 6 to 6.5 meters are constructed; four are located within the river bed, two are placed on the river banks on each side and two are outside the river bank. The bridge has been designed with strategic placement of piers to minimize obstruction in the river waterway… Once completed, the bridge will not only stand as a symbol of modern connectivity but also exemplify harmony between high-speed infrastructure and existing rail network.'
In Ahmedabad district, the Bullet Train alignment crosses multiple structures, including flyovers, bridges, railway lines, and Metro corridors. 'To maintain the mandatory vertical clearance of 5.5 meters from the topmost construction point as per IRC (Indian Roads Congress) guidelines, the piers of the Sabarmati River bridge have been designed with increased height,' NHSRCL said.
The advanced Balanced Cantilever Method has been deployed to construct the bridge across the Sabarmati river, which has a width of 360 metres. 'Balanced Cantilever Method is a specialised construction technique ideal for long span bridges over deep waters and rivers. The concept of this method is to construct a bridge without installing scaffolding systems under the bridge and complete the superstructure by sequentially joining the segments to form a span by post-tensioning and balancing the left and right from each pier using special erection equipment. This creates a continuous and stable bridge deck,' NHSRCL said.
While most river bridges on the Mumbai-Ahmedabad Bullet Train corridor typically have shorter spans of around 40 meters, the Sabarmati River bridge uses longer spans, ranging from 50 to 80 meters, to reduce the number of piers within the riverbed. 'The bridge comprises five spans of 76 meters each and two spans of 50 meters each. Each span consists of 23 segments being cast in-situ (construction at site). The casting of these segments requires meticulous precision, highly skilled workforce and dedicated team at every stage to ensure structural strength and quality… all foundation and substructure works have been successfully completed, the superstructure activities including pier head construction and segment casting are currently underway,' NHSRCL said.
To ensure the highest standards of safety during the bridge construction, a robust set of safety protocols have been put in place particularly for activities involving working at a height. 'A structured work permit system has been implemented to ensure strict accountability and discipline at site. All workers are strictly required to wear Personal Protective Equipment (PPE) including full-body harnesses at all times. To mitigate fall-related risks, catch nets have been installed below the Form Traveler/Bridge Builder structures. CCTV cameras have been installed for real-time monitoring of the construction process,' NHSRCL said.
The Sabarmati bridge is among the 21 river bridges in Gujarat. A total of 25 bridges are part of the MAHSR corridor from Ahmedabad to Mumbai.
