Utility Penetration Through Precast Double Tee Deck

[charliealphabravo]

I am locating a utility penetration in a school for a contractor who will core a 4" to 6" diameter hole through a double tee (8DT24) roof deck for a 4" dryer exhaust. I see various other similar and larger penetrations in the deck but I would like to see if there is any scientific method to properly placing them or if it is standard practice to use a sensor to avoid cutting deck reinforcement. I have chosen a spot at the middle of the deck span between the stems. I believe that only mild reinforcement should be encountered in the deck and that the pre-stressed tendons are in the stem.
Thanks in advance.

 

[msquared48]

4" to 6" is rather inconsequential for the slab portion of the double tee. And you are correct about the PS steel being in the stems. You should be OK of you stay 6" or so from the upper edge of the double tee section.

Mike McCann
MMC Engineering

 

[Ron]

Agree with Mike..I don't get excited about penetrations until they exceed 12"

 

[dcarr82775]

Warn the contractor of the obvious. I once had the contractor call and ask why if the flange was only 2.75" thick was his core driller still in concrete after 16 inches....