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Residential references WAS Re: Valley Rafters

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If a lateral design is required, the APA has a wealth
of good information, some of it very recent.  I
understand that some of their newer bracing methods
are being written into the 2006 codes.  I'm not too
well versed on that as lateral design is very uncommon
here in northeast PA.  Vertical loads are all about
developing the load paths and sizing beams
accordingly.  Hips and valleys and intersecting roof
lines are the big trick, especially when working with
architects who tend to ignore basic engineering

A great non-engineering resource is "Residential
Structure & Framing" from the editors of Journal of
Light Construction.  Its written more for builders,
but is very informative and explains residential
structures very well.

The Wood Frame Construction Manual has many design
tables and guides for prescriptive and engineered
design.  The other two resources I work with are the
NDS and Breyer's Design of Wood Structures.

And then there's always SEAINT if you can filter
through the political discussions...

Good luck with the residential design, and stay away
from signing entire house plans if at all possible.

Jim Wilson, PE
Stroudsburg, PA

--- "Randall Moore, PE, SE" <ranmoo(--nospam--at)> wrote:

> In that I have a strong interest in moving towards
> more residential design / analysis (from a
> background exclusively heavy industrial) and from
> reviewing this thread, there seems to be a myriad of
> ways to look at residential component design.
> Can you recommend resources (TEXT BOOKS, design
> guides, software, etc.) that can be used to design
> the components of a residential structure.
> Waiting for "Ophelia" in Southeastern NC!!!
> Randall Moore PE, SE
> Wilmington NC 
>   ----- Original Message ----- 
>   From: Nels Roselund 
>   To: seaint(--nospam--at) 
>   Sent: Saturday, September 10, 2005 2:02 PM
>   Subject: RE: Valley Rafters
>   Thor,
>   The design of a valley has more to do with the
> connections than with design of the member itself. 
> And it has to do with the roof structure as a
> system. The components of the system include the
> rafters, the ridges, valleys and hips, and the
> continuous double top plate.
>   In a rational and properly designed roof system,
> only the rafters need to be designed for flexure. 
> If the rafters are tied in each direction, their
> axial components of force resolve into an axial
> force in the valley or hip, so that neither the
> valley nor the hip acts as a beam.  However, as you
> follow the axial forces through the system, the
> forces at the connections can become pretty large,
> and even unmanageable.  And it can become
> impractical to tie rafters in each direction.  If
> you can't follow the axial forces through the system
> and resolve them all with designed connections, you
> should not hesitate to design ridges, valleys and/or
> hips as beams.
>   The conventional light-frame construction rules
> for framing can result in roof systems that cannot
> be rationalized.  Nevertheless, they seem to work
> O.K..  If they are not magical, perhaps, as Barry
> suggested, it has something to do with the
> buttressing or diaphragm action of the sheathing.  I
> have not figured out how to take advantage of the
> action of the sheathing in a gravity-load design of
> a roof-framing system.  
>   Nels Roselund, SE
>   South San Gabriel, CA
>   njineer(--nospam--at)
>   From: Avicpeng [mailto:vicpeng(--nospam--at)] 
>   Sent: Friday, September 09, 2005 3:04 PM
>   To: SEAINT
>   Subject: Valley Rafters
>   And just to start ... does anyone design the
> valley rafter of a roof, or do you write it off as
> "standard framing"?  If not, why not?  If so, why?
>   Thor Tandy P.Eng MIStructE
>   Victoria, BC
>   Canada
>   vicpeng(--nospam--at)

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