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Re: FW: Ceiling joists/rafter ties IRC R802.3.1

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Title: Re: FW: Ceiling joists/rafter ties IRC R802.3.1

The Wood Frame Construction Manual (WFCM) provides diaphragm capacities for gypsum sheathing (WFCM Supplement Table 2C) of 70 plf. http://www.awc.org/Standards/wfcm.html

Another publication on our website, Details for Conventional Wood Frame Construction http://www.awc.org/pdf/WCD1-300.pdf shows a detail in Figure 52 that might be helpful.

There's been no testing that I'm aware of.

HTH

Buddy


From: Jim Wilson <wilsonengineers(--nospam--at)yahoo.com>
Subject: Re: FW: Ceiling joists/rafter ties IRC R802.3.1
To: seaint(--nospam--at)seaint.org
Buddy,
That helps a lot considering it comes from the
"source." As Jordan alluded to, are there any
acceptable means of tieing roofs by means other than a
double layer of rafter tie? I.e., gypsum drywall,
diagonal struts, wall top plates in strong axis
bending, etc. And by acceptable, I mean by the code
or by testing and development of prescriptive-type
guidelines.
Thanks for the info!
Jim Wilson
--- AWC Info <AWCInfo(--nospam--at)afandpa.org> wrote:
> If it is a hip-beam system, there is no thrust... So
> it only needs to be
> tied together to resist out-of-plane wind loads...
> Analogous to a ridge beam
> system.
>
> If it is a hip rafter system (conventional
> construction), it needs to be
> tied together in both directions because the hip
> rafter is just a connection
> point... Analogous to a ridge board system.
>
> HTH
>
> Buddy
>
> John "Buddy" Showalter, P.E.
> Director, Technical Media
> AF&PA/American Wood Council
> 1111 19th Street, NW, Suite 800
> Washington, DC 20036
> P: 202-463-2769
> F: 202-463-2791
> http://www.awc.org
>
> The American Wood Council (AWC) is the wood products
> division of the
> American Forest & Paper Association (AF&PA). AWC
> develops internationally
> recognized standards for wood design and
> construction. Its efforts with
> building codes and standards, engineering and
> research, and technology
> transfer ensure proper application for engineered
> and traditional wood
> products.
>
> *********************
> The guidance provided herein is not a formal
> interpretation of any AF&PA
> standard. Interpretations of AF&PA standards are
> only available through a
> formal process outlined in AF&PA's standards
> development procedures.
>
> *********************
>
> >
> > From: Jim Wilson <wilsonengineers(--nospam--at)yahoo.com>
> > Subject: Ceiling joists/rafter ties IRC R802.3.1
> > To: seaint(--nospam--at)seaint.org
> > IRC R802.3.1 Ceiling Joist and rafter connections:
> >
> > "Where ceiling joists are not parallel to rafters,
> subflooring or
> > metal straps attached to the ends of the rafters
> shall be installed in
> > a manner to provide a continuous tie across the
> building, or rafters
> > shall be tied to 1-inch by 4-inch minimum-size
> crossties."
> >
> > Does this apply to the secondary direction in a
> > hip-framed roof? Some inspectors insist so, some
> > don't know, some don't know that they don't know.
> >
> > I've never seen it applied this way in the field,
> but
> > one prominent local builder has been specifying
> > two-way ties on their hip-roof structures. I would
> > like to either back them up, or save them the
> effort
> > and the consumer the added cost and inconvenience.
> >
> > Thanks in advance.
> >
> > Jim Wilson, PE
> > Stroudsburg, PA