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Re: Permit Requirement Question

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At 10:32 PM 11/8/97 -0500, Lew Midlam, PE wrote:

snip

>As I've written before, I consider the TPI requirement that the building
>designer design web stiffeners for the trusses to be analogous to having a
>pre-engineered building designer NOT be responsible for the design of
>cross-bracing or for the bottom flange bracing for uplift.  Luckily, I have yet
>to have a truss designer ask me to design web stiffeners for him

I agree with your comments with regard to bracing of the members of a truss.
I would not approve a submittal where the truss designer did not design the
bracing. Don't the computer programs generally in use by truss manufactures
do this automatically?

>My other pet peeve is TPI's requirement that the Building Designer design the
>truss anchors.  I've always wondered how I'm to do that without reactions,
which
>aren't calculated until after I've provided signed and sealed drawings to be
>submitted for permits, certifying that the design complies with the code.
Using
>the pre-engineered building analogy again, this would be asking me to
design the
>anchor bolts for the building.  I've yet to have a pre-engineered building
>designer not design the anchor bolts.

Clearly you would need the reactions, but isn't asking the truss engineer to
design the anchors asking him or her to design a part of the building that
the truss company will not furnish and will be installed by a contractor
totally beyond their control? What happens when the truss designer changes a
member in your building because of the connection design? The same goes for
anchor bolts which are dependant upon the concrete strength you select and
the edge distance your footing design provides. I have always felt that it
was the responsibility of the engineer for the manufacture of the
pre-engineered building to insure the anchor bolts had adequate capacity in
the base plates while it was the responsibility of the engineer of record
for the building to insure that the anchor bolts had adequate capacity in
the concrete footing.

Both of these examples provide good reason for the building department to
require complete plans and calcs and not allow deferred submittals. Deferred
submittals create planchecking inefficiencies, increase the possibility of
error and increase the planchecking time, which everyone will then complain
about.

Robert