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Re: Question on wood Roof Trusses

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I agree with Roger Turk, i tell the truss mfgr that they are responsible for
the design of the braces.  I also tell them i will provide the diaphragm to
support their braces, and i also show a detail that shows their brace
connecting to a nailer and what the allowable load  this nailer can transfer
to the diaphragm.

Ed Jonson



----- Original Message -----
From: "Neil Moore" <nmoore(--nospam--at)innercite.com>
To: <seaint(--nospam--at)seaint.org>
Sent: Friday, January 12, 2001 2:11 PM
Subject: RE: Question on wood Roof Trusses


> Dennis:
>
> You missed the point of the whole discussion.  The point is that some of
> the compression web's of these members have to be braced.  They are
usually
> braced back to the structure.  The loads have to be accomodated by the
> supporting structure.  The truss company has provided you with the values
> (although you have to hunt for them carefully in some of the truss
> company's output).  Everyone complains that this is a fairly messy
situation.
>
> If your local building department is only having you review the truss
> company's analysis, then they are not enforcing the code.  I'm not
> defending this situation; I'm trying to only to alert our community to a
> long term problem, especially submittals.   Our local building department
> requires that the bracing is completed before a permit is issued.  Review
> the 97 code section I mentioned and if you have the TPI code, that also.
> What you want to do and what you have to do are two different things.
>
> We're not talking about future codes - the problem is current - and with
> the litigation problems in this State, this is something to be aware of.
>
> Of course, I've always wondered how contractor's get their permits with
> projects that include prefabricated trusses that they've ordered over the
> phone and no engineer of any kind is involved.
>
>
> Neil Moore, S.E.
>
>
>
> >Roger,
> >I have not read all of the posts, however I did read Neil's last comment
and
> >this one from you.
> >I agree with you on this. The plated truss roof system is isolated as a
> >separate system in my area. The EOR is only responsible for the lateral
> >connection of the truss system to the structure and any gravity support
of
> >the girder trusses. A letter is required from the EOR that indicates he
or
> >she has reviewed the calculations ONLY TO VERIFY THAT THE CALCULATED
LOADS
> >ARE WITHIN COMPLIANCE OF THE ACTUAL LOADS USED IN THE STRUCTURAL DESIGN.
> >If I recall correctly, the latest code or upcoming changes in the next
code
> >require the truss company to provide more information including the
> >connection of truss to truss or truss to girder truss or truss to hip
etc.
> >
> >There is, in my opinion, a practical reason for this. The EOR does not
have
> >the resources to design the truss connections or even to verify if the
> >calculations are adequate since the truss analysis is based on
proprietary
> >values protected by the plate manufacturer.
> >
> >The second issue, in my opinion, would purposely keep the EOR from
assuming
> >any responsibility in the design of the roof system as to place the sole
> >responsibility for the structural integrity of the roof system upon the
> >plate manufacturer and the truss fabricator.
> >
> >While I agree that the information Neil brought up should be considered
in
> >the design of the roof, I am inclined to believe that this is the
> >responsibility of the truss manufacturer as all information on the loads
> >applied to the roof are provided by the EOR or Architect of record. To
> >become involved in a design that you have no control over is taking
> >unnecessary responsibility.
> >
> >The EOR, as I stated, IS responsible for the connections at points of
> >bearing of the roof system to the structure and the appropriate transfer
of
> >shear to the foundation.
> >
> >You May wish to consult the WTCA (Wood Truss Council of America) on this
> >issue - (http://www.woodtruss.com).
> >
> >Dennis
> >-----Original Message-----
>
>
>
>