CHENNAI: The state highways said the cost of the 3.2 km Teynampet–Saidapet four-lane elevated corridor under construction is Rs 390 crore (excluding GST), which works out to Rs 121.88 crore per km. It is the extra cost of Rs 231 crore due to certain additional components that took the total cost to Rs 621 crore.
An official note said the flyover’s design has been tailored for an “extremely sensitive urban context” with adherence to conditions imposed by CMRL as its metro tunnels are running underground at a depth of 11 to 14 metres.
The cost breakdown of additional components, besides the cost of flyover proper (Rs 365.19 crore), included: Soil stabilisation through advanced non-pressurised ground improvement techniques (Rs 38.92 crore), approach road, at-grade improvements, pier protection, illumination, and road furniture (Rs 24.69 crore), maintenance for 10 years (Rs 16.10 crore), shifting of service utilities (Rs 32.00 crore), price escalation of 5% (Rs 26.24 crore), supervisory consultancy charges (Rs 10.5 crore), instrumentation for CMRL tunnel (Rs 10.00 crore), others and contingencies (Rs 17.28 crore), and a GST of Rs 80.08 crore.
To minimise load dispersion on the tunnels, the flyover used steel pillars and composite girders with a nominal span arrangement of 30 metres. The cost of constructing a steel flyover is not comparable with a conventional Reinforced Cement Concrete (RCC) structure, the note said.
The note was shared after TNIE’s report on August 18 about why the flyover is the most expensive of its kind in the state in terms of cost per kilometre, which highlighted the cost escalation due to soil stabilisation and other challenges. However, officials had not offered a detailed explanation with cost breakdown despite requests.
Rs 39 crore extra cost for soil stabilisation via advanced non-pressurised ground improvement techniques