The Hyderabad Metro Rail Limited made a record of sorts on Sunday surpassing Mumbai, Bangalore and Chennai Metro Rails by completing 38 per cent (27 km of total 72 km) of the total viaduct in shortest period of time (20 months) with the construction of 1,000th span of the total 2,665 spans. The HMR authorities said that Mumbai took about seven years to complete 11 km of Metro viaduct, Bangalore and Chennai took over five years to complete about 25 Km of viaduct each and Delhi took more than three years to achieve the same.
1,000 pillars built in a short time of 27 months
The officials said that it has created an all India construction record on Sunday by completing 27 Km of Metro viaduct in just 20 months. The first viaduct between two pillars was erected near Genpact in Habsiguda in December 2012. The 1,000th completion span was 38% of the viaduct works (out of a total of 2,665 spans required for 72 Km) so far. The Chief Minister K Chandrasekhar Rao congratulated the HMR MD N V S Reddy and his team of engineers in HMR and L&T for the engineering record achieved by Hyderabad.
N V S Reddy said that this kind of spectacular engineering feat of fast construction in congested roads of Hyderabad with a good safety record was possible due to a number of proactive measures taken by the state government and HMR and the engineering capabilities of L&T. The MD said that as on Sunday, 1,473 foundations (56%), 1370 pillars (52%) are completed. State government facilitated setting up of India’s two biggest precast yards, one at Uppal in 70 acres and another one at Qutubullapur in 62 acres.
L&T established factory-like precast yards with sophisticated machinery like automatic steel cutting and bending machines etc., to produce precast segments each weighing about 40 tons. These precast segments are being transported in the night on low bedded trolleys to various Metro construction sites and erected between Metro pillars with the help of ‘launching girders’.
In all, 15 launching girders are being used to carry out these erection works simultaneously at several spots. While the average length between 2 pillars is 100 feet which is bridged with 11 precast segments, the average length between 2 station pillars is about 50 feet which is bridged with six precast segments. After dry matching these prearranged segments, they are glued and tied with a bunch of iron strands from inside, which are elongated to their maximum capacity in ‘post tensioning’ method and then permanently grouted. The so erected viaduct spans can withstand heavy loads and 21 types of stresses caused by two running trains and natural forces including heavy gales and earthquakes.
The HMR authorities said, this kind of precasting method where almost 85 per cent of the Metro works including station construction are precast, has facilitated super-fast construction and minimum inconvenience to road users. Usage of state of the art shuttering material, single pour of concrete up to 40 feet height with very good surface finish, usage of curing compounds instead of conventional water curing, multilevel quality checks ensuring safety and good quality works and other global best construction practices have already won Hyderabad Metro several international and national awards including ‘The Global Engineering Project of the Year’ award for 2013 at the 6th global Leadership Forum in New York, RoSPA Royal Society for Prevention of Accidents) ‘Gold’ awards for 2013 and 2014 at Glasgow (UK), ‘Metro Rail Project of the Year 2013’ at Mumbai, etc., stated the L&T Metro Rail Hyderabad Limited MD V B Gadgil.