Strip Footing Minimum Thickness ???

[TekEngr]

what is the minimum strip footing thickness as per American and British code with T & B layer of Steel ??
below is the general sketch of strip footing with PCC slab so my question is that we should pour the concrete monolithically (pouring of concrete for strip footing and PCC Slab together) or first we should pour the strip footing and then PCC floor slab which way is better in structurally and site convenient point if view ?
if we pour the concrete in footing and slab together can i get the more resistance against uplift and what will be the connection between footing and floor slab however the floor slab is PCC ???

thanks in advance

 

[jayrod12]

Minimum width is generally dictated by loading and recommendations in the geotech report (the geotech recommendations are quite often governed by settlement).

I've done it both ways in terms of pouring monolithic or in 2 separate pours. A lot of the time it depends on whether the client is willing to accept a cold joint on either side of the footing. And in the case of two separate pours, you could provide dowels to tie the slab and footing together.

 

[901STR]

Minimum thickness of the footing will likely be dictated by several issues:
- ACI 318-11, Section 15.7 requires a minimum depth above the bott reinforcement no less than 6". with cover of 3 inches below and reif. diameter, you are looking at a min of 10"

-Look into section 1809 of IBC 2012. There a a few requirements listed. 1809.4 lists the depth of the footing at a minimum of 12" below undisturbed soil (this does not mean the footing must be 12" thick, but it must bear 12" below undisturbed ground). It also mentions it must bear below frost line (1809.5), however I don't think this applied to you since your detail appears to be from an interior wall. section 1809.7 also has prescriptive values for footing supporting lightweight walls if a design in not provided (must meet all conditions listed in table, and thickness vary from 6 to 8").

- check geotech report as suggested by jayrod12.

 

[dik]

How does ACI 318-11 treat plain unreinforced concrete? I've often used 8" min thickness.

I usually put a sawcut at one of the sloped edges in contact with the 4" slab. For bottom reinforcing, I usually do a 45deg bend in lieu of a 90 degree bend extending the rebar to the top reinf layer.

Dik

 

[901STR]

ACI 318-11, section 22.7.4 says plains concrete footings shall not be less than 8".
But, since this particular footing is reinforced, I wouldn't' think it applies.

 

[dik]

901STR: Thanks... and would agree... but, wouldn't likely use less than 8"... reinforced or otherwise.

Dik