The National High Speed Rail Corporation (NHSRCL) has erected the first full span pre-stressed concrete (PSC) box girder of 40 mtr span in a casting yard in Navsari district in Gujarat.
This 40 mtr full span box girder weighing about 970 tonne, involving 390 cu mtr of concrete and 42 tonne of steel was cast in a single piece i.e. without any construction joint on 1 November 2021.
This is also the heaviest PSC box girder in the construction industry of India. To expedite the construction of a viaduct for Mumbai-Ahmedabad High-Speed Rail Corridor, NHSRCL is adopting full span launching method.
The precast girder was picked up from the stacking yard by the straddle carrier and moved to the predefined location from where it was lifted by the bridge gantry for erection.
The 40 mtr full span girder was then placed between Pier P11 and P12 at Ch 238 of MAHSR Corridor. The height of the piers is 13.4 mtr from the ground level.
To expedite construction of a viaduct, construction of substructure and superstructure has been taken up in parallel.
While the work of substructure i.e. pile, pile cap, pier and pier cap is in progress, for superstructure, casting yards have been developed along the alignment to cast full span girders and segmental girders so that they can be launched using heavy machineries over the cast pier caps.
Twenty-three casting yards are being developed along the alignment for casting of full span girders of 30,35 and 40 mtrs. Each casting yard is spread in an area of 16-93 acre as per requirement and located near to the high-speed rail alignment.
The planning of casting yards and heavy machineries for launching has been done in a way to meet peak requirement of superstructure casting and erection.
For expeditious casting of girders with quality, facilities like jigs for making rebar cage, casting beds with hydraulically operated pre-fabricated moulds, batching plants, aggregate stacking area, cement silos and labour camps have been developed in each casting yard.
The Mumbai Ahmedabad High-Speed Rail Project is 508 km long. Out of 508 km, 352 km lies in the state of Gujarat (348 km) and Dadar & Nagar Haveli (four km) and balance 156 km lies in the state of Maharashtra. Out of 352 km, the civil contracts of 343 km are already awarded.
Larsen & Toubro (L&T) is the executing agency for 325 km length, through two packages awarded to them i.e. C4 (237 km) and C6 (88 km).