Flat Plate 2 Way Concrete Slab Thickness - Mild Reinforced 1

[neffers]

For those of you out there who have quite a bit of experience with 2 way flat plate construction...what sort of slab thickness would you expect for a 32'x32' bay size? I know ACI has minimum thickness requirements, but that doesn't seem thick enough once you take into account long term deflections. What have you used for deflection criteria? Any info is greatly appreciated. Thanks!

 

[hokie66]

Try this for starters. I wouldn't use a flat plate for those bay sizes. As per page 17 of that reference, reinforced flat plates are normally not economical beyond 7 metres, or about 23 feet. But when you design flat plates, the first check to make is for punching shear.

http://www.ccaa.com.au/imis_prod/do...es/CCAAGUIDE2003-T36-Long-span floors-TBR.pdf

 

[neffers]

Hokie66...thanks for the link, I will check it out. Believe me...I am not the one pushing the issue. I agree with you. Perhaps my terminology wasn't correct either, perhaps I meant flat slab i.e. including column drops for punching shear. The punching shear isn't really what concerns me, it is the long term deflections.

 

[hokie66]

As it should. Yes, a flat slab is a possibility. Or maybe a banded slab.

 

[rapt]

neffers

You have left out a lot of information needed to work it out, but I would say in the order of 375-400mm (15-16") slab with drop panels the same depth again and about 10' square!

 

[dik]

Hokie, easily worth a couple of stars... great publication.

Dik

 

[hokie66]

I didn't write it, but it is a handy reference.