NHSRCL casts another Full Span Pre-Stressed Concrete (PSC) Box Girder of 40 Mtrs span in the casting yard in Navsari, Gujarat. Last month, on 28th October the first Full Span Girder was casted in the casting yard at Anand, Gujarat.
PSC Box Girder of 40m span weighs around 970 MT, will be the heaviest PSC Box Girder in the construction industry of India. The 40m Span Girder is being cast as a single piece i.e. without any construction joint, involving 390 Cum of Concrete and 42 MT of steel.
To expedite construction of 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 casted Pier Caps.
Most of the Girders for Superstructure will be of Full Span 30,35 & 40 Meter long, however, for locations where there is site constraint, Segmental launching of precast segments will be used. Full Span Girder are preferred over Segmental Girder as Full Span Girder launching progress is seven times faster than Segmental Girder launching.
For casting of Girders 23 casting yards are being developed along the alignment. Each casting yard is spread over an area of 16 to 93 acres as per requirement and is located adjacent to the High-Speed Rail Alignment. 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, quality laboratory and workmen camps have been developed in each casting yard.
The full span pre-cast box girders will be launched using heavy machineries like Straddle Carrier, Bridge Launching Gantry, Girder Transporter and Launching Gantry. To ensure continuous supply of girders for launching, the box girders will be cast in the casting yards in advance and stacked in a systematic manner. The Straddle Carrier will lift the Box Girder from the stacking yard and will feed to the Bridge Launching Gantry, which will lift the Box Girder and place the Girder over the bearings on Pier Cap. Bridge Launching Gantry will launch first 3-4 box girders, on which Girder Transporter will be placed and further launching of Girders in sequential manner will continue for further kilometers using Girder Transporter and Launching Gantry.
Planning of casting yards and heavy machineries for launching has been done in such a way so as to meet peak requirement of approx.300 Full Span Box Girder Casting and Launching in a month, which equals to approx.12 Km. of superstructure casting & erection in a month.
Mumbai-Ahmedabad High Speed Rail Project (MAHSR) is 508 km long. Out of 508 Km, 352 Km lies in in the state of Gujarat (348Km) and Dadar & Nagar Haveli (4Km) and balance 156 Km lies in the state of Maharashtra. Out of 352Km, M/s L&T is the executing agency for 325Km length, through two packages awarded to them i.e. C4 (237Km) and C6 (88Km).