Multiple Sleeve holes in Concrete FDN Wall

[MyCupboard]

I'm looking for some guidance as to what limitations, or design strategies you all use for multiple sleeve penetrations in a concrete fdn wall. Typically, we have a detail that puts some extra bars around it to prevent cracking and to transfer the load around the hole. But for this project, i have concrete walls, varying 11' to 13' tall, that are 16" thick and they have approximately (50) penetrations (spread out over 5 different walls) that vary from 2" to 5". most of them they are requesting to be horizontally aligned and 12" apart from each other.

At first, my boss and I were thinking, why can't they just run their penetrations up through the slab. But then figured we would try to come up with a solution for the wall penetrations as they requested. Then we were considering asking them to align them vertically (or at least some of them vertically) instead of aligning 10-12 holes horizontally at 12" o.c.

I have had trouble finding any guidelines or calculations or codes regarding multiple holes so close together. Not sure if i'm overthinking it, or on the flip side if this is a major issue.

 

[Gr8blu]

Did the ones asking for penetrations indicate what they were for?

My guess, based on number and size, is that these are either for liquid conduit (water, oil, etc.) or electrical (wire inside protective/supporting conduit) or both. If the assumption is correct, the runs are generally horizontal for distribution, with vertical runs exposed to get to where the final connection needs to be - which in turn means that orienting the openings vertically within the foundation wall(s) is not an option.

 

[MyCupboard]

we have flexibility. they are for various utilizties: water, sanitary sewer, electrical, low voltage (electrical), and communications.
They said we have some flexibility in moving them, but i honestly don't even know what resources to check out at this stage. my first instinct is to get them into some amount of columns so that it is disrupting less length of wall, then treat it like a concrete beam spanning an opening (but the opening is just the bank of holes).

as of this point, i've proposed to them a few clusters of holes with that beam concept to see if that's acceptable to them. i just want to make sure i'm not overlooking an important analysis piece to this.

 

[Gr8blu]

You'll be limited (by code) on how close the different systems can be to one another - and possibly how close you can put different electrical voltages as well. As top orienting the holes to run the conduit vertically - do you want to get called whenever there is a leak and have to pull down the WHOLE WALL to get at the pipe problem?

Likewise, you probably cannot set the holes for the water piping over the electrical piping (and vice versa) - particularly if the next piece of either pipe heads toward the bank of holes you just placed above it.

 

[MyCupboard]

You'll be limited (by code) on how close the different systems can be to one another - and possibly how close you can put different electrical voltages as well. As top orienting the holes to run the conduit vertically - do you want to get called whenever there is a leak and have to pull down the WHOLE WALL to get at the pipe problem?

Likewise, you probably cannot set the holes for the water piping over the electrical piping (and vice versa) - particularly if the next piece of either pipe heads toward the bank of holes you just placed above it.

I am just the structural engineer. I don’t care at all what is going inside the holes, I just need to design the holes so the foundation wall doesn’t fail and looking for some guidance. Unfortunately; by this point I have already needed to submit my design to the contractor. So what’s done is done.