Minimum thickness of concrete slab to put only single reinforcement layer

[h-badawy]

Dear experts

In the Egyptian code the minimum slab thickness to put only one single layer of reinforcement is 16cm because of shrinkage otherwise you have to put second layer.
I don’t know what is the corresponding value in the ACI-code maybe it is same.
my question is what is theoretical reason for this value(16cm) and also if we don’t have any tension force and we did an ideal curing during construction so what is the need of the shrinkage additional layer ?
Thanks

Thank you

 

[r13]

16cm thickness is quite reasonable for slab with single layer reinforcement Quite a few times I've seen 5" (127mm) or less (with wire mesh) were used. I won't go that far though. Below is ACI recommendation on thickness of one way slabs. And for two way slab, the minimum is 125mm (ACI318-11).

 

[hokie66]

Is this for slabs on ground or for suspended slabs? Do you mean the maximum thickness for only one layer?

 

[MotorCity]

Minimum thickness = minimum top cover + bar diameter + minimum bottom cover

 

[Agent666]

I'd add to motorcity's condition by saying you also need to satisfy balanced strain conditions which may mean you need more cover depending on the reinforcement and spacing requirements.