Electrical Conduit in CMU walls

[bbartlet]

Where can I find information regarding the effects of electrical conduit inside structural CMU walls? A contractor wishes to run the conduit horizontally in the wall, which would obviously cross through the grouted cells. They also want to place vertical conduit in cores that are to be reinforced and grouted. Is this acceptable practice?

 

[msquared48]

Aluminum conduit - NO!!!!!!!!!!!!!

PVC OK, but ask for his placing plan and make him stick to it.

Mike McCann
MMC Engineering

 

[bbartlet]

It is metal conduit, but I don't believe it's aluminum. We have already told them that they could not place vertical conduit in the walls. I just want to know for future reference. Is there a problem running it horizontally or vertically in the walls as long as it's not aluminum or not in contact with the rebar? Would the voids created by the conduit through the cores weaken the prism strength of the CMU wall?

 

[jike]

It is done all the time, except, I would have them place it in ungrouted vertical cores. Comply with requirements in ACI 530.

 

[hokie66]

I wouldn't have a problem with pvc or galvanized conduit vertically, whether in grouted cells or not. Horizontally, it can be a concern depending on your stress conditions and the conduit size.

 

[civilperson]

The rigid metal conduit has an equal or greater strength than the grout that it displaces and may be used in any orientation with good consolidation.

 

[Zambo]

Very interesting reply civilperson. What about pvc?

I don't see any reason that the conduits need to be in the vertical cores which are to be grouted.

 

[concretemasonry]

If you have vertical runs of conduit to decrease the amount of hotizontal runs, that make good sense.

If you have good engineering and resulting open cores, the only logical thing is to put the conduit in the open cores from a practical constructabilty standpoint and also for cost. Puting conduit in a grouted cell with rebar only decreases the structural liability. Doubtful if you have any cores that are grouted without reinforcement in them.

Dick