Minimum Reinforcement Ratio In Concrete

The minimum amount of steel reinforcement is defined as that for which "peak load at first concrete cracking" and "ultimate load after steel yielding" are equal. In this way, any brittle behavior is avoided as well as any localized failure, if the member is not over-reinforced.

A minimum area of reinforcement is required to control the cracking, which occurs in the concrete due to temperature, shrinkage and creep. It enables cracking to be uniformly distributed and therefore minimizes individual crack width.

The minimum ratio of required reinforcement is;

For Shear Walls:

• For horizontal direction : 0.0025
• For vertical direction : 0.0025

For Slabs:

• For one way slab : 0.002 (for both direction)
• For two way slab : 0.0035 (for both direction)

For columns :

• For longitudinal reinforcements : 0.01