Reinforced Concrete Design - Structural holes 2

• Feb 14, 2021

1
• #2

jayrod12

Structural

Mar 8, 2011

6,304

CA

Obviously it isn't ideal, but I don't see the issue with it provided you do the appropriate punching shear checks taking into account the affect of the hole. The effect on punching shear isn't just the reduction of the hole width on the failure surface, but the projected width of the hole at the punching shear perimeter. The further you can keep any holes away from the column, the less of an impact they have on the total failure surface.

 

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• Feb 14, 2021

1
• #3

KootK

Structural

Oct 16, 2001

18,690

CA

I design pretty much every interior column punching zone assuming that there will be one 6" penetration right beside the column. Coordinating the placement of integrity top bars around the penetration often warrants some careful attention.

 

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• Feb 23, 2021

• Thread starter
• #4

architrave

Structural

Aug 21, 2008

6

US

Thank you very much guys!

 

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• Feb 23, 2021

• #5

WARose

Structural

Mar 17, 2011

5,594

US

Is there a rule of thumb in placing holes?

Click to expand...

You generally try to have openings in the "middle" strips (where possible). See Sect. 13.4 of ACI 318-11 for some guidelines.

What you are talking about can be done (with the checks performed).

 

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• Feb 24, 2021

• #6

Lomarandil

Structural

Jun 10, 2014

1,936

US

WARose is correct for the most common case of flat plate/flat slab floors.

Note that in the less common case of two-way beam-supported slabs, the ideal location is in the intersection of column strips (but not in the beam). Depending on your floor, some shear and deflection checks may still be required, but these are generally easy to solve.

----
just call me Lo.

 

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