Metro viaducts and stations
What it is
Elevated or underground structures that carry urban metro lines.
How it works
Precast segments or U-girders span between piers; stations are frames above or boxes below ground.
Diagram: Indiacon original, not to scale.
Main components
Piers, pier caps, segments or girders, bearings, station concourse and platforms.
Key codes
IRS codes, IS 456, IS 1343. Cited by number only; get the text from BIS or the issuing body.
Notable projects
Chennai Metro, Kolkata East–West Metro, Melbourne Metro Tunnel (Australia).