Metro Viaduct over Punjagutta flyover accomplished

The completion of the Metro Viaduct over the Punjagutta flyover has come as a welcome feat for commuters in the area. The final product is an iconic arch-shaped viaduct crossing the existing flyover and showcasing L&T's engineering skills and talent.

Appreciating the aesthetics of the sleek structure, the Chief Minister K Chandrasekhar Rao stated that Hyderabadis would be proud to see and enjoy the simultaneous movement of road vehicles at the road level and over the flyover and of the Metro trains on the viaduct.

Of the 85 odd traffic junctions in the city, which needed to be crossed by the Metro Rail viaduct, the construction of the viaduct over Punjagutta flyover proved to be the toughest. Being a busy location in the heart of the city, with an already existing flyover, volumes of traffic from different directions and the need for accommodating higher future traffic volumes posed engineering challenges in the design and execution of the viaduct.

Instructed by Chief Minister K Chandrasekhar Rao to convert this challenge into an opportunity and create an engineering showpiece for the city, HMR Managing Director NVS Reddy held brain storming sessions with VB Gadgil and Project Director MP Naidu of LTMRHL, HMR CE Md Ziauddin and Heads of L&T Construction C Sankaralingam and KS Reddy to evolve design and construction strategies.

Taking the height of the existing flyover (23 ft) into account, the Metro viaduct was planned to cross it at double elevation at a height of 51 ft from the road level. To allow future growth of traffic volumes, the central span over the existing flyover was designed as a 190 ft long span supported by high tensioned tendons, which are anchored to adjacent spans of 115 ft each on both sides.

As the headroom available from the top level of the existing flyover to the bottom part of the Metro viaduct is only 21 ft, special type of shuttering and girder arrangements by restricting them to only 7.5 ft height was designed to get enough clearance (height) over the flyover for allowing vehicular movement during the construction stage.

The entire construction was carried out without halting the traffic of any direction even for an hour viz. the BanjaraHills-Begumpet and Ameerpet-Khairatabad directions and vice-versa. This was done by devising ground supported staging with wide gaps in between, leaving enough carriageways for traffic flows at the road level and over the flyover during the construction period.

After carefully arranging the support staging in such a manner, concreting of the viaduct, positioning and stressing of tendons, arrangement of bearings and removal of support shuttering were all carried out in nine stages over a period of four months.