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RE: Metal Building Notes and Other Gripes

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Comments below.  Some stuff deleted for brevity.
--- "Effland, Greg" <geeffland(--nospam--at)butlermfg.com> wrote:

Stuff deleted
> 
> 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?

Generally, I would prefer that embedment be included in the design.  By the
time I receive metal building submittals, the foundation reinforcing submittals
have usually been reviewed and returned, and the GC has approved those drawings
for fabrication.  By that time it is too late to alter foundations design.

So...

Stuff deleted


> 
> 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. 

Agree.
 
> 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.  

Disagree.

Again, I would prefer you specify anchor rod embedment length, concrete mix
design minimums, and tie requirements, should you feel the last two are
necessary.

> 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.).

Agree.

> 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.

Agree.

Portions of this are news to me.  I will hereafter specify pre-installed
anchors, and permit post-installed anchors only after a change is requested.
> 
> 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.

Disagree.

Design structural engineers do not get paid for designs after the contract is
bid.  [Yeah, that's a gross generalization, but exceptions to it make the
rule.]  Such is the nature of the industry.  Either the GC must hire a
"foundation" engineer, or the EOR must do the work after the contract for
construction is awarded.  ALL I NEED IS THE EMBED.  If you can provide that,
even with a long list of caveats and clauses, I'm good.  If nothing else, it
gives us a starting point.
> 
> 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?

Not the foundation configuration (though that's often ignored).  Just give me
an embedment length.  If it doesn't fit in the foundation, I'll fix it, or
we'll talk about alternatives.

-Keith Fix, PE
-Little Rock, AR

> 
> Respectfully,
> Greg Effland, P.E.
> KC, MO USA
> 
> 


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