1. the tensile strength of steel is much more times greater than concrete.
2. Steel is also ductile in nature.
3. Steel has also the high strength to weight ratio as compared to concrete.
4. Steel structures are also preferred when time span is small. Construction rate is very fast.
5. Steel bars are also reusable. 
6. Steel structures can be extended in any direction.
7. Steel has smaller columns as compared to concrete columns, so do to this more space will be available for some other functions.
8. as steel structures are lighter then concrete, therefore there is less cost used and foundation of structure become less expensive.
9. Steel structures are cost-effective