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RE: Premanufactured wood trusses without

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This brings up an interesting question of liability. In my area, the EOR is
not responsible for manufactured truss calculations - only the compliance of
the truss to the "intent" of the structural design and conformance to code
Live and Dead loads.
I'm not sure how it is handled in other areas, but one problem that I would
foresee is that if you questioned the validity of the calculations (which I
have even though I implied that I don't) I found that you will not get the
cooperation of the truss engineer who stamped the truss package. If I
insist, I get put in the advisarial position between the owner who is
anxiously waiting for his permit, the contractor how is waiting to break
ground and the Architect who is waiting to get paid.
Tough position when you find that a truss manufacturer is not providing you
the information you request and only gives the package that he knows the
City will accept based upon his stamp.
The upside is that the EOR of the structure is only liable for the
connection of the truss as part of the load path. If a truss fails, the
manufacturer and his engineer who calculated the trusses becomes the liable
On the downside, it is our (the EOR) responsiblity to bring any error to
their attention and to the attention of the building official, however, we
can not necessarily make him correct or justify his design.

Any comments?

Dennis Wish PE

-----Original Message-----
From: Roger Turk [mailto:73527.1356(--nospam--at)]
Sent: Thursday, October 29, 1998 10:15 AM
To: seaint(--nospam--at)
Subject: Re: Premanufactured wood trusses without


If the person that you talked to cannot tell you any more than "the program
...", then he/she has no idea what the program did/does and is merely
someone else's calculations.

I would not accept anything until I was satisfied that the trusses were
appropriately designed.

AFIK, ICBO, or anybody else, does not issue approvals for computer programs.

Is the truss designed for unbalanced loading?

Good Luck,

A. Roger Turk, P.E.(Structural)
Tucson, Arizona

. > I am reviewing a truss submittal where the truss manufacturer has used a
. > rectangular panel in the truss in the center to make room for duct and
. > some light equipment.  When I asked about the moments in the members
. > around the rectangular panel, I was told that the program is designed to
. > handle panels without diagonals and that the interaction equation shows
. > the effects of axial and bending forces. When asked about the ability of
. > the connector plates to transfer moments, I was told that an ICBO report
. > would be faxed to me.
. >
. > I would like to know if others have reviewed trusses like this and what
. > comments they have.
. >
. >