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ACI 318 7.7 covers requirements for cover when designing rebar placement within concrete. However, they are for general components and makes no exceptions for small irregularities such as lifting hook anchors that one may wish to place. I am not an expert with concrete so I wondered if anyone can point out to me whether there are exceptions to these requirements and whether these minor irregularities are actually required to have the same cover requirements, or are they small enough that it's usually not a significant concern.

Example of hook lift anchors: https://meadowburke.com/product/hook-lift-anchor/ https://meadowburke.com/product/hook-lift-recess-former/

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So, actually, I am more curious about the recess that I am putting in as you can see within that catalogue (I added a link above). It's obvious that the recess can reduce cover for some of the rebars involved, and I wondered if that will be an issue or whether or not that will create issues later. Any advice?

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Yes, the ACI Standard 318 does specify “Concrete protection for reinforcement” (cover) for various issues, including: 1) standard placement in “principle structural members”, 2) reinforcement in extremely corrosive atmospheres, 3) fire protection, 4) bars, inserts and plates intended for future expansion, 5) precast construction.

In (4) it makes a statement that it must provided “adequate covering”. It states that it’s for protection against corrosion, but could imply bonding too. (See ACI-318 808 (f). Note: I have an old edition from 1963 (I’ve been doing this awhile), but I’m sure it’s similar to current editions.)

In your case, if the inserts cannot be placed such that they leave adequate “cover”, to the nearest reinforcing, then adjustments must be made. I’d say that includes recessed pockets that could allow “standing water”.

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  • $\begingroup$ So, I am placing these on the side of concrete precast structure, so it's unlikely that it will actually collect water. I also would be open to painting the depression with something to provide "adequate cover". Will that work? Or is that not acceptable per general industry practices? $\endgroup$ – Isa Nov 23 '20 at 17:39
  • $\begingroup$ If the recess will not collect water (especially corrosive water) AND you can maintain edge distance from rebar, then there is no issue. However, if your edge distance from rebar is less than what ACI requires, then additional steps must be taken....or be prepared for unsightly rust stains and structural failure due to inadequate cover. (Corrosive staining can come from fog, mist, etc. it doesn’t have to be standing water.) $\endgroup$ – Lee Sam Nov 23 '20 at 18:13
  • $\begingroup$ If I don't want to epoxy the bar, can I paint the concrete? Will that resolve the cover issue? $\endgroup$ – Isa Nov 27 '20 at 0:55
  • $\begingroup$ Paint rated for concrete is best. If the paint is exposed to the elements, plan on regular maintenance (repainting every 2-3 years). $\endgroup$ – Lee Sam Nov 27 '20 at 2:52
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By definition, embedded items that stick out of the concrete have to have a reduced concrete cover. Otherwise they wouldn't stick out of the concrete.

What you see specified in the ACI code is concrete cover over reinforcing steel that is serving some long-term purpose. The minimum concrete cover is specified to provide corrosion resistance.

Lifting hooks typically aren't required long enough in the future to worry whether they are corroded or not. If they are required in the future where corrosion could be a concern, then they would need to be protected from corrosion in some way. This is the same as any other embedded item like a connection plate. These ways are typically galvanizing, epoxy coating, or painting if the part is not already made of a corrosion resistant material like stainless steel.

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    $\begingroup$ It's also worth mentioning that though cover constraints aren't relevant for anchors, anchors are a possible infiltration point and should therefore be taken into consideration when calculating cover for other rebars. $\endgroup$ – Wasabi♦ Nov 21 '20 at 0:18
  • $\begingroup$ Hmm, what about the recess? Do I need to account for that as well? $\endgroup$ – Isa Nov 22 '20 at 6:11

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