Concrete Shear Wall Penetrations

[brquigle]

I have an existing concrete shear wall. There's a proposal to core out some holes. The California Building code requires a full upgrade of the wall if the wall's capacity is decreased by more than 5%. Let's say the wall is 7" thick, 10'-0" long, and the hole penetration is cirular with a diameter of 3".

ACI 318-08, Section 11.9 has provisions for shear capacity of walls. They appear to be based solely on the length of the wall.

Could I just say that pre-penetrations d=0.8L, and after penetrations, at the location in question, d=0.8(L-Dhole)? Then calculate capacities and see if 5% was lost?

 

[csd72]

It really depends if it is shear critical or bending critical, but if the hole is in the middle third then bending shouldnt be the issue.

I would take the new shear length as 0.8L - DHole as the 20% reduction is for the section in tension and your hole may not coincide with this.