A first: Runway over river in TN

By K S Sravanan

The southern metropolis will by next year have something in common with Atlanta, Brooklyn and Madeira Island—a runway across a river.

A year from now, aircraft using the secondary runway at Chennai airport will make its run for take-off over a bridge across the Adyar river. The Airports Authority of India (AAI) has started construction work to extend the 2,035-metre secondary runway by 1,400 metres, including 835 metres on the northern side of the river. The AAI is getting technical assistance from IIT-Madras as the river is flood-prone. Mumbai airport has an end of its runway across the Mithi river, but this stretch is used only for taxiing.

The existing runway ends on the banks of the river. A bridge, to be designed similar to that of a box culvert, will be constructed across the river and the runway will extend over it towards the north. Land filling and levelling works that started December-end are progressing well to meet the 2010 deadline. The state government has acquired 120 acres and handed over to AAI for the project.

The extension of the secondary runway is being carried out at a cost of Rs 430 crore. “The runway work without the bridge will cost Rs 230 crore, while construction cost of the bridge is estimated to cost Rs 200 crore,” said a senior AAI official.

KGL Constructions has bagged the contract to build the runway excluding the bridge, while a separate contract will be awarded for the bridge construction. “The tender will be awarded very soon,” said airport director K Natarajan.

“The extended secondary runway will help us operate one departure for every arrival, which will be highly useful to manage peak-hour traffic. The secondary runway intersects the primary runway only at the end portion near the GST Road side of the airport. This leaves the entire runway free for operation. The runway can also be used as a taxiway when a parallel runway is constructed,” he added.

An official at the engineering wing said the runway construction would be completely mechanised, completing the faster than conventional methods.

“We have taken all precautions to prevent water from flooding the runway. AAI had been monitoring the flood levels for the last couple of years. The runway level is going to be at least one-and-a-half metre above the highest flood level marked during the 2005 rains.”