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RE: Wood interior wall studs

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Might as well go all the way and use 2.0 for impact loads - that is what the
NDS says. 

-----Original Message-----
From: Joseph R. Grill [mailto:jrgrill(--nospam--at)cableone.net] 
Sent: Friday, July 13, 2007 1:03 PM
To: seaint(--nospam--at)seaint.org
Subject: Re: Wood interior wall studs

1.0 for the people on the floor, 1.6 for the additional "impact" for the
bodies diving off the stage.  Sorry haven't designed any mosh pits lately.

Joe
----- Original Message -----
From: "Haan, Scott M POA" <Scott.M.Haan(--nospam--at)poa02.usace.army.mil>
To: <seaint(--nospam--at)seaint.org>
Sent: Friday, July 13, 2007 1:56 PM
Subject: RE: Wood interior wall studs


Do you design a mosh pit floor with Cd=1.6 or 1.0?

-----Original Message-----
From: Joseph R. Grill [mailto:jrgrill(--nospam--at)cableone.net]
Sent: Friday, July 13, 2007 12:50 PM
To: seaint(--nospam--at)seaint.org
Subject: Re: Wood interior wall studs

"impact" being an important descriptive word, therefore, 1.6 Cd.


----- Original Message -----
From: "Andy Heigley" <aheigley(--nospam--at)jgaeng.com>
To: <seaint(--nospam--at)seaint.org>
Sent: Friday, July 13, 2007 1:45 PM
Subject: RE: Wood interior wall studs


> Actually the 5 psf is due to HVAC.
>
> Here's and excerpt from the IBC Handbook:
>
> "According to BOCA/NBC, the requirements of this section, reproduced from
> the 1999 BOCA/NBC section 1606.9, are intended to provide sufficient
> strength and durability of the wall framing and wall finish, so that a
> minimum level of resistance would be available to nominal impact loads
> that
> commonly occur in the use of a facility and to HVAC pressurization."
>
>
>
> Andrew Heigley, PE
>
>
>
> -----Original Message-----
> From: Haan, Scott M POA [mailto:Scott.M.Haan(--nospam--at)poa02.usace.army.mil]
> Sent: Friday, July 13, 2007 4:25 PM
> To: seaint(--nospam--at)seaint.org
> Subject: RE: Wood interior wall studs
>
> I think the 5 psf is intended for people slam dancing on the walls - not
> for
> pressure from HVAC.  The IBC has the 5 psf in the Live Load section. The
> 97
> UBC says the 5 psf is "L" and does not need to be applied with wind or
> seismic.
>
> I would use the 1.15 Cr and 1.0 for Cd for the 5 psf.
>
> -----Original Message-----
> From: Joseph R. Grill [mailto:jrgrill(--nospam--at)cableone.net]
> Sent: Friday, July 13, 2007 12:16 PM
> To: seaint(--nospam--at)seaint.org
> Subject: Re: Wood interior wall studs
>
> There is also repetitive member increases in bending.  15% usually, but
> the
> code allows 50% if a wind load.
> Joe Grill
>
>        ----- Original Message -----
>        From: Jordan Truesdell, PE
> <mailto:seaint1(--nospam--at)truesdellengineering.com>
>
>        To: seaint(--nospam--at)seaint.org
>        Sent: Friday, July 13, 2007 1:07 PM
>        Subject: Re: Wood interior wall studs
>
>        I do a lot of wood, and here's my take:
>
>        The 5psf should be at a Cd of 1.6.  Why? Unless I have an
> intentionally pressurized room (which is not the case here), there is no
> possible way that common construction techniques can _maintain_ that kind
> of
> pressure differential over an extended period of time, and if you have a
> constant load (say, a commercial kitchen with doors that seal
> tight...right...) making the pressure differential then the HVAC engineer
> should already be providing makeup air in that area.  The building code
> can
> call it a "live" load all it wants, but the actual duration of load will
> never reach 10 years in the 50 year design life of the building.
>
>        Roof live load should be given a Cd of 1.25; snow is 1.15.
>
>        I don't recommend a loadbearing wall of 10' in height be made of
> 2x4s. Why? Because the walls will not be sheathed before the floor joists
> are
> set into place. The code limits the L/d ratio to 75 for construction, and
> a
> 10' 2x4 has an L/d of 80. The contractor cannot build the wall unless he
> plans on bracing every stud without violating the code.
>
>        And, for the record, I agree with Don that 2x4s 10 feet long look a
> lot like spaghetti. And as a bearing wall they give me the willies. My
> answer
> to such a request is normally to do it as designed, or provide another PE
> to
> seal off on the change with full calculations, and provide me with a full
> release of liability should anything happen.  I've never been taken up on
> the
> offer.
>
>
>        Jordan
>
>
>        Andy Heigley wrote:
>
>                Everyone:
>
>                <!--[if !supportEmptyParas]--> <!--[endif]-->
>
>                Thanks for your responses...
>
>                <!--[if !supportEmptyParas]--> <!--[endif]-->
>
>                Here are my responses to some of your questions back:
>
>                <!--[if !supportEmptyParas]--> <!--[endif]-->
>
>                *       I would design for LL and LLr if the wall were
> supporting both the floor and roof loads.
>
>                <!--[if !supportEmptyParas]--> <!--[endif]-->
>
>                *       I am designing to ASD.
>
>                <!--[if !supportEmptyParas]--> <!--[endif]-->
>
>                *       I guess I'm a little leary of using the Cd of 1.6
> for
> this reason.  The duration factor is applied to both bending and axial
> capacities.  Applying 60% more to the allowable axial stress makes a huge
> difference.  And if you have a 4 story building, for example, you are
> going
> to be approaching the capacity of the stud just due to DL and LL...  you
> then
> add a "little bit" of short term horizontal loading to the stud and
> increase
> the capacities by 60% seems non-conservative.
>
>                <!--[if !supportEmptyParas]--> <!--[endif]-->
>
>                *       Scott:  I haven't found the rated wall design
> reduction factors you've mentioned.  Can you tell me the code section that
> is
> in?
>
>                <!--[if !supportEmptyParas]--> <!--[endif]-->
>
>                *       10'-0" high 2x4's... exactly why I initially called
> for 2x6 stud walls, but the GC is flipping out about it... I get the old,
> "I've been doing this for 30 years, and never had to do this before"...
>
>                <!--[if !supportEmptyParas]--> <!--[endif]-->
>
>                <!--[if !supportEmptyParas]--> <!--[endif]-->
>
>                Andrew Heigley, PE
>
>                <!--[if !supportEmptyParas]--> <!--[endif]-->
>
>                <!--[if !supportEmptyParas]--> <!--[endif]-->
>
>                <!--[if !supportEmptyParas]--> <!--[endif]-->
>
>
>
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