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Braced Wall Panel and ICF walls

BayPointArchitect

BayPointArchitect

Sawhorse
Joined
Oct 19, 2009
Messages
516
Location
Lincoln
Given:
The contractor has selected ICF walls (insulated concrete forms).
The building official requires that I show compliance with braced walls per R602.
My thinking is that the ICF blocks are inherently shear walls and this requirement surprises me.
ICF walls do not consist of the typical 2 x 6 wood studs that a structural wood panel would normally nail or staple into.

Question:
So is it legitimate for me to call out where the braced wall panels are located within a "continuously sheathed structural fiberboard" - or CS-SFB - that wraps around the entire house?
Something about this does not make sense to me.

I have attached my foundation plan that illustrates where the braced wall panels will be nailed at 3" and 6" on center.

Thanks in advance.

ICC Certified Plan Reviewer
NFPA Certified Fire Plan Reviewer
 

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seem to me it would be treated like a CMU wall with its reinforcement

2015 IRC section 608

solid wall for resistance to lateral forces
 
Last edited:
ICF foundation or above grade walls? IRC 608 is for concrete above grade walls. I wouldn't think you use 602 since there is no wood.
 
Would R608.7 Solid Walls for Resistance to Lateral Forces help?

R608.7.1 says:
"Each exterior wall line in each story shall have a total length of solid wall required by Section R608.7.1.1. A solid wall is a section of flat, waffle-grid or screen-grid wall, extending the full story height without openings or penetrations, except those permitted by Section R608.7.2. Solid wall segments that contribute to the total length of solid wall shall comply with Section R608.7.2."
 
Might check with the manufacturer. In Canada the major ICF manufacturers have joined forces to create a standardized, engineer-crafted set of reinforcing tables for shear walls in all kinds of seismic and wind configurations; I would anticipate the US side would have done the same?
 
The official response from the ICF manufacturer includes a copy of Section R608 of the 2018 IRC and several pages of ICF wall details. I am not certain which part of those 59 pages was meant to be helpful. The AHJ plan reviewer has said that the waffle-grid provided by the standard ICF does not qualify as a "solid wall". But I see Paul Sweet has given the IRC definition of a solid wall which includes the waffle-grid. Meanwhile, I have spent an hour trying to research the "screen-grid-wall" concept and I still do not have a clue.
 
In my opinion this is another example of an attempt to apply the IRC to situations not contemplated. I believe that the appropriate approach is to use the IBC.
 
Is this a foundation wall? If so how much unbalanced backfill? What type of soils do you have?
Personally I would never use a 6" flat wall for a foundation wall let alone a waffle grid ICF form.
 
No basement. Single story residence located above grade. Maximum wind speed = 115 mph. Seismic zone "B".
Because I don't think that the IBC has anything specific for above-grade concrete walls, I am thinking that the applicable codes would be ASCE 7 and ACI 318. And ACI 318 section 14.3.5 requires that reinforcement be spaced no more than 18 inches on center.
 
BayPointArchitect said:
No basement. Single story residence located above grade. Maximum wind speed = 115 mph. Seismic zone "B".
Because I don't think that the IBC has anything specific for above-grade concrete walls, I am thinking that the applicable codes would be ASCE 7 and ACI 318. And ACI 318 section 14.3.5 requires that reinforcement be spaced no more than 18 inches on center.
Click to expand...
The IBC references ASCE 7 and ACI 318
The IBC does not have prescriptive provisions for this case but an engineer can, by using the standards in the IBC, either determine if it complies or if changes are needed.
 
What is your wind exposure category? Truss length
R608.2 Applicability limits.
The provisions of this section shall apply to the construction of exterior concrete walls for buildings not greater than 60 feet (18 288 mm) in plan dimensions, floors with clear spans not greater than 32 feet (9754 mm) and roofs with clear spans not greater than 40 feet (12 192 mm). Buildings shall not exceed 35 feet (10 668 mm) in mean roof height or two stories in height above grade.
 
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