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Looking for strategies to make a wood floor behave like a rigid diaphragm (as much as practical)

Looking for strategies to make a wood floor behave like a rigid diaphragm (as much as practical)

Looking for strategies to make a wood floor behave like a rigid diaphragm (as much as practical)

(OP)
This may be common:
I have a house under construction (so currently in framing stage) with a garage portion having narrow walls in front and solid walls on three sides with a full floor above.
The framers did not run the header full width (as per the drawings that were indicated to achieve the "Narrow Wall Bracing" details).
Naturally I can make them do it over but what I really want is some ideas for making the floor above as much like a rigid diaphragm as I practically can so that the three solid walls can work for me.

I have 18" I joists spanning side to side 16" o.c. and 3/4 plywood subfloor bearing on 2x6 studs.
Joist span is about 24 ft and 18" depth is used so that it matches joist depth from another location having a greater span (so, joists are well within their capacity for the gravity loads).

Thoughts, ideas, reference materials?

Steve

RE: Looking for strategies to make a wood floor behave like a rigid diaphragm (as much as practical)

Quote (HouseBoy)

Thoughts, ideas, reference materials?

All I have is some thoughts. In a three sided building scenario, I don't believe that you need to hit any particular rigidity target in order to ensure rigid diaphragm behavior. We're generally only interested in the rigid/flexible designation when diaphragms are statically indeterminate with regard to load distribution to their supports (shear walls, braces, etc). In a three sided building, the diaphragm is statically determinate and you'll know just how the support reactions are distributed to the three walls.

One caveat: three sided building diaphragms warrant extra attention to detail when it comes to:

a) assessing deflection at the free end of the diaphragm and;
b) establishing a competent load path for your chords.

Quote (Jayrod)

I don't believe you can get significant diaphragm capacities using the i-joists.

I hadn't yet seen this. Thanks for sharing it.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

RE: Looking for strategies to make a wood floor behave like a rigid diaphragm (as much as practical)

We often use cross laminated timber slabs to achieve rigid diaphragm. Ofcourse we could use joists and OSB but in the end it's not that expensive and a lot easier to build. I don't know how common CLT is in North America, but here in Europe it's getting more and more popular, especially for floors.

Structural timber engineering

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