The reinforcing steel—rods, bars, or mesh—absorbs the tensile, shear, and sometimes the compressive stresses in a concrete structure. Plain concrete does not easily withstand tensile and shear stresses caused by wind, earthquakes, vibrations, and other forces and is therefore unsuitable in most structural applications. There were 25mm, 20mm, 16mm diameter bars are used in construction of tunnel. There were M25, M20, M15 grade of concrete is used. For more details and information download drawing file.
