Anna Salai’s 3.2-km Elevated Corridor Above Metro Tunnels Gathers Pace

Work on the much-awaited 3.2-kilometre elevated corridor on Chennai’s Anna Salai, a project estimated at ₹621 crore, is steadily gaining momentum. The corridor is being built directly above the Metro Rail tunnels between Teynampet and Saidapet, making it one of the most technically challenging infrastructure projects currently under execution in the city.

According to officials, more than 30% of the construction has already been completed. Special engineering solutions are being adopted to ensure that the twin Metro tunnels remain unaffected throughout the process. Instead of piling, isolated footing foundations are being used in tunnel stretches, while pile foundations are applied in non-tunnel areas. Additionally, soil layers are being reinforced with geo-textile and deep soil mixing techniques to guarantee long-term stability.

The use of steel structures has further reduced the load on the tunnels, while high-precision equipment has been installed inside the Metro tunnels and stations to monitor any potential movement or deflection. These systems provide real-time alerts to station control rooms, ensuring safety standards are never compromised.

Highways department officials have confirmed that nearly 50% of the foundation works are now complete. The target is to finish all foundation activities before the onset of monsoon, so that construction of the superstructure can continue without major interruptions during the rains. To speed up progress, both manpower and machinery at the site have been tripled in recent weeks.

Experts from IIT have also vetted the design, confirming that tunnel pressures remain well within permissible safety limits. With Anna Salai carrying close to two lakh vehicles every day, this elevated corridor is expected to significantly ease traffic congestion while offering a safer and more efficient transport link.

Once completed, this corridor will not only decongest one of Chennai’s busiest arterial roads but also stand as a landmark engineering achievement — the first elevated road of its kind built directly above operational Metro Rail tunnels in the city.