I want to ask about the minimum ratio of steel for mat foundation?

[Sbander]

HI
I want to ask about the minimum ratio of steel for mat foundation (RAFT)?
Thank you

 

[boo1]

ACI-ASCER Committee 326 "Shear and Diagonal Tension" part 3, "Slabs and Footings", "ACI Journal Proceedings", Vol 59, No. 3, March 1962, pp353-396

ACI Committee 436 "Suggested Design Procedures for Combined Footings", "ACI Journal Proceedings", Vol 63, No. 10, October 1966, pp1041-1058

check ACI 10.5.3 and 7.12.2 for min steel reinforcement

 

[Wopshistos]

if you have not gone down to the library yet to look that lot up the answer you are looking for is simple. Around 0.2% minimum - but even that can go down depending how you designed the thing to work.
Less than 0.15% is a bit mean and might lead to problems as far as crack control goes.
Thick slabs can be designed using the "marzipan" technique to cut down on % but you need to know what you are doing for that.
Hope that helps.

 

[rmonterroso]

Wopshistos:

Could you please be more specific on the meaning of 'marzipan' technique?

Thanks