Concrete Footing Clear Cover 1

[SeizeTheMoment]

What do you typically use as your specified clear cover? Per ACI318-14, Sec 20.6.1.3, a specified cover of 3" must be used for concrete that has an exposure of "against and permanently in contact w/ ground."

I typically see footings that have reinforcements T&B with 2" clr on top, 3" from bottom, and 3" on the sides. Do you also follow ACI's specifications for the top reinforcements?

Thanks,
S.T.M.

 

[hokie66]

3" when cast against the ground. 2" might be OK for top, if the top of the footing is finished. What's the top reinforcement for?

 

[TLHS]

I basically reinforce all of my footings on the top because I'm in a pretty high seismic area and I'm generally of the opinion that even if it's a situation where you aren't using the weight of soil on top as part of the calculations, it's going to mobilize against it in a high deflection scenario in an earthquake. So my assumption is that a cone of soil could get picked up by the footing as it tries to overturn or uplift.

 

[hokie66]

That's good reasoning, TLHS. The same would apply to high wind areas. But top bars are a waste in lots of areas. They also can contribute to plastic settlement cracking if compaction is less than optimum.