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Re: Does AISC Seismic Section 11.2a apply to MBMA ordinary moment connections?

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> From: "Mark D. Anderson PE" <mark(--nospam--at)>

> > Does AISC Seismic Section 11.2a apply to MBMA ordinary moment 
> > connections?

I can't address Scott's original question directly but I have some
general comments.

> I suspect a number of us are waiting for a clear response....

In order to get a clear response, you have to ask each manufacturer
individually. Neither MBMA or AISC determines the practices of
individual manufacturers and not all manufacturers are MBMA or AISC
members. Whether a manufacturer follows the letter of the code will
depend on their sophistication. It is also possible that, despite the
apparent practices, they may meet the requirements of the code.

As I have said several times on this list, the PEMB manufacturers are
not exempt from designing their structures to the same design standards
as a conventional steel structure BUT you need to be aware of all the
nuances of the standards and read the commentary/footnotes/reference
documents. The PEMB manufacturers can afford to optimize their designs
in ways that nobody else can economically touch without investment in
the design tools.

But this doesn't answer the original question.

> There are special divisions in the MBS industry that deal with 
> heavy/industrial structures, and these entities can and will perform the
> design and manufacture to the AISC Seismic Provisions-2002.  But their
> systems generally bear little resemblemence to the MBS systems we are
> accustomed to. 

It would seem that you have experience with specific project(s) of this
nature. When you get beyond the simple stand-alone "shed" you will find
a group of designers dealing with more sophisticated aspects of design.
When things start to fall outside the proprietary software, design
starts to look more conventional.

These issues usually arise from (as I call them) second tier suppliers.
If the manufacturer doesn't have the right personnel resources, you may
get less than you expect but everything that you paid for.

> The question is, what about everybody else competing for the remaining
> 98% of the MBS market?.

That's why the customer (EOR) must be very careful when selecting the
supplier/manufacturer pair to ensure that they can deal with the special
requirements. Don't accept the word of the design/build GC's sales rep
(who probably doesn't know a kip from a kipper), go straight to the
engineering dept of the manufacturer BEFORE awarding the contract. Put
it in your specs as an explicit requirement. The onus is on the
manufacturer to prove that their design meets the EOR's requirements if
those requirements are appropriately defined in the RFQ/order to the
manufacturer (e.g. by code reference). On the other hand, don't be a
stick in the mud if they can prove adequacy (no smoke and mirrors) in
ways that you don't anticipate.

> Mark D. Anderson
> Anchorage

Is this apparent geographically localized interest related to a
substantial project that was recently awarded in your neck of the woods?
Just wondered because I had some design scheduling inquiries (now gone
past) ...

Paul Ransom, P. Eng.
Burlington, Ontario, Canada
<mailto:ad026(--nospam--at)> <>

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