concrete cover

[FRAN11]

During placement of a foundation for a vertical wall, some of the rebar shifted. When the wall was laid out the cover over the rebars (#6) measured about 3/4". what is the tolerance for acceptable cover?

 

[astructurale]

ACI 318-05 7.7.1:
Concrete cast against earth - 3" cover minimum
Concrete exposed to earth or weather - 2" cover minimum (#6 - #18 bars)

You don't meet code if you are in the US. However, in the commentary it says that if you have an alternate method of protecting the reinforcement from weather you may use it but but you still must meet the cover for conditions not exposed to weather, which in this case would be 3/4" cover minimum (lucky you!).

I would guess that some type of water proofing may be adequate, or you may try painting the surface with a coat of epoxy or resin to act as a barrier. One of the major manufacturers like Sika,

http://www.sikaconstruction.com/,

may have a recommendation for you.

Also, your clear cover is equal to your bar size. If it were less than the diameter of the bar you'd need to use a modification factor on your bar development calculations which could affect the strength of your wall. (See ACI Chapter 12 if you need more information on this.)

Good luck!

 

[henri2]

Tolerance for reinforcing steel cover in walls depends on the effective depth (d).

If the effective depth (d)> 8 inches, the tolerance is minus 1/2 inch but for d values less than or equal to 8 inches it is minus 3/8 in. ACI 318 Section 7.5.2.1