[Greenbuilding] Advanced framing/OVE / 100 years from now

[Rob Tom]

On Thu, 08 Mar 2007 21:25:39 -0500, John Salmen <terrain at shaw.ca> wrote:

> Virtually equivalent meant 'serves the purpose' compressive loading @ 24"
> o.c.. works.
>
> lateral stability with wall sheathed for spf 'stud' grade (which I would
> assume all lumber to be even if marked #2) is 675 psi so the numbers are
> much higher for loading than your giving. We are talking about interior  
> wall loading here not exterior subject to wind loading.
[snip]
>
>> FWIW, for stud-grade SPF dimension lumber "2-bys" 2400mm long (~8 ft),
>> laterally-supported (ie by sheathing), using ... Limit States Design  
>> (LSD)procedurefor compression members, (ie Pr =  
>> phi*Fc*A*Kd*Ksc*Kt*Kh*Kc) and a quickie back-of-the
>> envelope calc, then the axial load capacity of:
>>
>>    a 2x4  = 12.7 KN (~ 2850 lbs)
>>    a 2x6  = 22.8 KN ( ~5116 lbs)

John;

FWIW, the value used for "Fc" (specified strength in compression parallel  
to grain) in the above equation was 5.9 MPa  (ie 856 psi...actually higher  
than the 675 psi number you mention), as specified by CSA Standard  
CAN3-086.1-M84 for #3/Stud grade SPF Light Framing lumber, as were all of  
the other variables in the equation so the axial load capacities mentioned  
above are appropriate and accurate for the criteria mentioned .

I'm not sure what you mean by "interior wall loading" in your comment  
above.

I was under the impression that the example you provided (2x4 studs @24"  
o/c with 3.5" EPS in the bewteen-the-studs cavity + insulating sheathing  
on one face of the studs) was referring to an exterior wall. In  
residential buildings, exterior walls are usually carrying the gravity  
loads from the roof which in my locale, includes live loading due to snow.

=== * ===
Rob Tom
Kanata, Ontario, Canada
<A r c h i L o g i c   at  c h a f f y a h o o   dot   c a >
winnow the chaff from my edress in your reply