ACI 318 Code

[Ky_Su]

Hello there Structural PEs and EITs.  I have a practical Code question for you.  I believe ACI 318 requires something like 2 to 3 inches of concrete cover over steel rebars to prevent corrosion (among other things).   If the wall of a reinforced concrete vault is cored for electrical conduit and causes the rebar to be exposed, is that an ACI 318 code violation?  Thanks!

 

[PowerStroke79_PE]

Whenever this happens, and it happens often, I always specify an appropriate seal to the penetration on both sides of the vault. Take a look at products like Flexicraft or others to make sure the penetration is done well. Is the vault going to be below a water table? If so, I recommend using a hydrophilic seal around the pipe on each side of the vault (assuming no finishes are placed over the seal). You may also want to look into the Concrete Repair Manual by ACI as their should be good information on an appropriate approach. 

I wouldn't allow the concrete coring to stay exposed. Make sure the penetration is sealed. 

This is my take, others may have different opinions. Below is the ACI Clear Cover requirements by ACI 318-14. 

 

[PE - Jack of All Trades]

I agree. You don't want the rebar to be exposed. Ideally, you don't want the rebar to be exposed in the first place. The cover requirement is for potential crack that could expose the rebar. If you seal the core, corrosion will more than likely not happen. I would still be very careful with the letter and specify it's a repair and corrosion can still happen but this repair will significantly reduce the likelihood. 

 

[Ky_Su]

Thank you for the inputs.  @PowerStroke79_PE  The vault (precast concrete) is not below water table.  Did you specify the sealing product(s) for the reinforced walls you designed or someone else's design?  If the latter, did you seek input from the EOR? 

Just to be clear... I'm not seeking info for my design/report.  Just happened to see something on a record drawing that piqued my curiosity.  

 

[PowerStroke79_PE]

Thank you for the inputs.  @PowerStroke79_PE  The vault (precast concrete) is not below water table.  Did you specify the sealing product(s) for the reinforced walls you designed or someone else's design?  If the latter, did you seek input from the EOR? 

Just to be clear... I'm not seeking info for my design/report.  Just happened to see something on a record drawing that piqued my curiosity.  

I've noticed MEP's, Structural, and Civil always toss around these specs like hot potatoes actually. I guess in the end it will be about liability and not responsibility. However, I always like to add notes regarding penetrations. I cite ACI as much as I can and note recommendations on engineering judgement if necessary. The problem I've always seen is contractors trying to get away with not coring. They end up chiseling till they reach the other side. Don't get me wrong, sometimes that's the only method available. Anyways, yes I call out certain products and "or provide equal." I make sure all parties are involved when it comes to observations.