characteristic strength of concrete

[Anonymous]

hello,everyone,
Why when i am change the (characteristic strength of concrete) from grade to another the quantity of steel remain the same , especially in foundation ???thanks....

[Refaat]

Hi @hazim.slevane

Could you attach specific  example to clarify your inquiry ?

Refaat

[Romanich]

It might happen in the case when you have only minimum reinforcement according to a design code.

[Anonymous]

It is normal. It is not by increasing the strength og the concrete that you'll change a lot the reinforcement ratio (with the same effort).

Try with an excel sheet to see..

[Anonymous]

Do you mean there isn't relationship between concrete strength and steel ratio????

[Anonymous · Accepted solution]

No but the tensile strength of concrete is less or neglected in the fiber subjected to tension. So that it does not impact really your sizing.

Look to the formulae calculating the As...