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Re: OOP Wall Anchorage - min. size of wood framing member

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I haven't looked at the new code to see yet, but he is talking about
the wall anchorage sub-purlins in a tilt-up or masonry building, not
the ledger (they frame into the ledger) where you would have a
side-bolted HD, PHD or something and nails from the diaphragm above
meaning a lot of penetrations from both faces in a short distance.

Maybe the gang-nail truss people got them to rescind it or simply
using something like a 2x8 or deeper takes care of the concern.

-gm

On Nov 26, 2007 2:17 PM, WISH DENNIS <dennis.wish(--nospam--at)verizon.net> wrote:
>
>
> If you are refering to a ledger type connection then the recommendation is
> to use a minimum 3x member regardless of whether it still specifically
> exists in the code or not (I have not checked the new code to see). The
> depth of the top flange of the hanger generally governs the ability to use a
> 2x or 3x min ledger connector. Originally, the concern was in cross-grain
> tension failures caused by top flange hangers that pull against the top of a
> wood ledger creating a bending failure parallel to grain - but this was
> generally a concern where the mass of the wall exceeded a wood stud wall
> such as in tilt-up, masonry or concrete buildings with wood ledgered walls.
> Still, the problem was not resolved by simply using a 3x minimum ledger, but
> by making sure that the framing was concentrically connected to the masonry
> or concrete wall directly through the purlin, or sub-purlin and not using
> the ledger for a tension connection.
> If you are only concerned with wood framing on wood stud walls, I would
> still recommend a minimum 3x connection because of the available length of
> embedment of the 10d or 16d nailing. You can order a Simpson N10 nail that
> is 1-1/2" long but conventional nails are somewhat longer and withdrawl on
> the nail is related to depth of embedment which means that you will take a
> loss if using a shorter embedment length of the nails.
> So to answer you directly, I am not sure what the code requires since I have
> not gotten that far in the new code, but I would still recommend a 3x or 4x
> ledger for all connections of wood against wood and especially so if you use
> a top flange hanger.
>
> Dennis
>  Dennis S. Wish, PE
> California Professional Engineer
> Structural Engineering Consultant
>
>
>
>
> ----- Original Message ----
> From: "sutej(--nospam--at)ca.rr.com" <sutej(--nospam--at)ca.rr.com>
> To: seaint(--nospam--at)seaint.org
> Sent: Monday, November 26, 2007 12:45:52 PM
> Subject: OOP Wall Anchorage - min. size of wood framing member
>
> 1997 UBC Section 1633.2.8.1 required the wood framing member of the wall
> anchorage assembly in seismic zones 3 and 4 to have a minimum net thickness
> of 2 1/2".  I do not find this requirement in the 2006 IBC, 2007 CBC, nor in
> ASCE7-05.  Is this no longer required and, therefore, a 2x member could be
> used?
>
>
>
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-- 
-gm

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