Hi Siddiq Shaik

The minimum and maximum percentage of steel in concrete elements depends on the type of element, the design code and the loading conditions. Different codes may have different criteria for determining the optimal amount of reinforcement to ensure adequate strength, ductility and serviceability of the structure. Here are some examples of the minimum and maximum percentage of steel as per some international codes:

• According to IS 456:2000, an Indian standard for plain and reinforced concrete, the minimum percentage of steel in beams is 1%, the maximum is 2%, the minimum in columns is 1%, the maximum is 6%, the minimum in slabs is 0.7%, the maximum is 1%, and the minimum in foundations is 0.7%, the maximum is 0.8%1.
• According to ACI 318-19, an American standard for building code requirements for structural concrete, the minimum percentage of steel in beams and one-way slabs is 0.75% for Grade 60 (420 MPa) bars or 0.5% for Grade 40 (280 MPa) bars, the maximum is limited by the spacing requirements and the strain compatibility, the minimum in columns is 1% for spiral reinforcement or 0.8% for tied reinforcement, the maximum is 8% for spiral reinforcement or 6% for tied reinforcement, and the minimum in foundations is not specified, but it should be sufficient to resist cracking and provide adequate anchorage2.
• According to BS EN 1992-1-1:2004, a British standard for design of concrete structures, the minimum percentage of steel in beams and slabs is determined by the crack control requirements, which depend on the exposure class, the concrete cover, the bar diameter and the stress level, the maximum is limited by the ultimate limit state design and the serviceability limit state design, the minimum in columns is 0.8% for normal conditions or 4% for fire conditions, the maximum is limited by the confinement requirements and the buckling resistance, and the minimum in foundations is not specified, but it should be adequate to resist punching shear and bending.

These are just some examples of international codes that provide guidance on the percentage of steel in concrete elements. There may be other codes that have different specifications and requirements. It is important to consult the relevant code and design standards for each project and follow the best practices of structural engineering.

for more information :

https://civilbasics123.com/percentage-of-steel-in-concrete-for-beams-columns-slabs-and-foundations-civil-engineering-building-design/

https://www.concrete.org/publications/internationalconcreteabstractsportal.aspx?m=details&ID=12452

https://www.civilengineeringweb.com/2023/10/percentage-of-steel-beam.html

https://codes.iccsafe.org/content/IBC2015/chapter-22-steel