Q. Minimum and maximum area of reinforcement?

Minimum area of reinforcement vs. maximum area of reinforcement

Beams can be designed to be larger than required for strengthconsideration because of aesthetics or other reasons. As such, corresponding steel ratio is very low and moment capacity of pure concrete section based on the modulus of rupture is higher than its ultimate moment of resistance. Consequently reinforcement yields first and extremely wide cracks will be formed. A smallest area of reinforcement is specified to avoid the formation of wide cracks.

Contrariwise, a maximum area of reinforcement is specified to allow the placing and compaction of fresh concrete to occur easily.