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Re: Metal Building Notes and Other Gripes

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Greg,

Skipping the rhetorical questions for the most part (HVAC designers ARE
responsible for the attachment of their units to the structure, including
spring isolation systems, base curbs, or whatever)  and recognizing that:

A. I did not indicate that the PEMB manufacturer should be responsible for
the foundation design, only the required Anchor bolts (i.e. attachment)

B. The "facts" portion of your post was most informative.  If indeed the
PEMB engineer provides layout, diameter and required force for the anchors I
stand corrected.  My impression from the previous posts was the information
is not typically so complete.

As I stated, I do not and have not worked with metal building projects.  But
a couple of additional observations / questions from the comments so far:

As the PEMB I would think it would be necessary for you to ensure the
connection of your frame system to the foundation is consistent with your
analysis.  Do you review the foundation design relative to your building
design?

I agree the base plate will not "know" whether the anchors are pre or post
installed, but to design a base plate for post installed anchors the
required capacities and spacing requirements of the post installed anchors
will dictate the anchor pattern. Inherently you must make an implied
assumption regarding the type of anchors to be used, and the available
footing geometry,  your pattern with the specified diameter bolts must be
capable of developing the required forces.

Respectfully,

Paul Feather PE, SE
pfeather(--nospam--at)SE-Solutions.net
www.SE-Solutions.net
----- Original Message -----
From: "Effland, Greg" <geeffland(--nospam--at)butlermfg.com>
To: <seaint(--nospam--at)seaint.org>
Sent: Wednesday, November 27, 2002 11:08 AM
Subject: RE: Metal Building Notes and Other Gripes


> Sounds like the light pole manufactures provide a minimum embedment that
we
> don't.  Does that really help out the foundation designer to a great
extent?
> If it does then repeatedly ask for it...  if enough people want it we will
> provide it.
>
> But what if the designer wants a different type of anchor bolt due to
> geometry restrictions and a lesser embedment is required than what we
might
> specify?  Should the designer be tied to providing only what we specify?
> What if the footing ties into the slab?  Should we then design the slab,
> retaining wall and all other pieces connected in some indirect way to the
> building?  Should we design the sprinkler systems on the lot so that we
can
> control the moisture content of the clays around the footings to avoid
> differential settlement?  Somewhere a reasonable line must be drawn.  The
> HVAC designers don't design the joists which support their equipment and
the
> frames which support those joist and the footings which support those
> frames...  Why not? aren't all of those things required to support their
> equipment?  Doesn't that leave them with no proof that their design is
> adequate or achievable?  They don't just hang in the air...  Why is this
the
> expected procedure for HVAC and "completely inappropriate" for PEMB?
>
> Enough rhetorical questions, here are some facts:
>
> 1) PEMB manufacturers ARE responsible for determining the diameter and
> placement of the anchor bolts.  Typically A307/A36 material is assumed for
> the anchor bolts.
> 2) Embedment length, concrete mix (strength, slump, etc.), tie
requirements,
> etc. are not determined by the PEMB manufacturers and the chosen design
> requirements may not even be known by us.
> 3) All of the required information to design the frames and base plates is
> known by the PEMB manufacturer.  (Reactions, Bolt diameters, bolt
patterns,
> base plate dimensions, welds to columns, etc.).
> 4) Your comments regarding pre or post installed anchors are correct.  We
> MUST know if they are pre or post installed.  For the case of post
installed
> anchors (which is the exception for us) the uplift cones and anchor
> manufacturer recommendations and/or design procedures are used for
> determining adequacy of the anchor.  For post installed anchors you still
> need to make sure that the concrete slab/footing can handle the loads from
> the anchors...  Again we have no reasonable way to check the adequacy of
> that.  As far as the base plates, they don't care if the anchors are post
or
> pre installed.
>
> With all of this in mind, giving the designer: 1) the size of the anchor
> bolt, 2) minimum material properties for the anchor bolts, and 3) the
> reactions, this seems like a fairly solvable problem (designing the anchor
> bolt embedment and footing sizes) yet this approach also offers a lot of
> flexibility for the footing "expert" to come up with an efficient design.
>
> Do you really want someone who has no knowledge of the concrete mix being
> used, slab layout desired, quality of soil on the local jobsite (more
> detailed than what is required for seismic calculations) to determine the
> anchor bolt embedment and foundation configurations?
>
> Respectfully,
> Greg Effland, P.E.
> KC, MO USA
>
>
> -----Original Message-----
> From: Paul Feather [mailto:pfeather(--nospam--at)SE-Solutions.net]
> Sent: Wednesday, November 27, 2002 10:43 AM
> To: seaint(--nospam--at)seaint.org
> Subject: Re: Metal Building Notes and Other Gripes
>
>
> I have been reading this thread with interest.  I typically will not get
> involved in Metal Building Projects, so my comments are form the "outside"
> so to speak, and not from any direct experience.
>
> The single item that strikes me in the positions / communications from the
> metal building manufacturers is the point that you do not design and are
not
> responsible for the anchor bolts that attach your buildings to the
provided
> foundations.  This in my opinion is completely inappropriate.  If you do
not
> design the anchor bolts, how do you design the base plates?  How can you
> separate yourself from the realities of whether or not the anchor bolts
are
> pre or post installed?  If the end product is going to require
> post-installed anchors, the anchor bolt layout and the base plate need to
be
> compatible with the capacities of post-installed systems, with all the
> spacing and embed requirements considered.  How do you know if your design
> requirements are even achievable?
>
> It is one thing to provide an anchor bolt requirement with delineated
force
> requirements to another engineer to enable the appropriate design of the
> foundation system.  It is quite another to design in a bubble and absolve
> yourself of any responsibility for how your structure is attached.  Even
> light pole manufacturers provide specific base plate and anchor bolt
> requirements, including size and embedment.
>
> Just my opinion.
>
>
> Paul Feather PE, SE
> pfeather(--nospam--at)SE-Solutions.net
> www.SE-Solutions.net
>
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