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RE: REFERENCE TO HSS MOMENT CONNECTION

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Bill,

I apologize for not being specific enough.  It is my understanding that if
you want to sacrifice the benefits of a higher R factor (i.e. designing
with a smaller seismic load), then there are situations where you can
still design and detail moment frame systems that does not require
testing.  This would be that case that you mention of using an R of 1 (or
maybe even an R of 3 or less).

It is my understanding that if you want to use an R factor associates with
an ordinary, intermediate, or special moment frame system, then such a
moment connection either needs to be pre-approved (i.e. one of the
connections tested for FEMA 350 which was only on specifically sized WF
beam to WF columns) or have such a connection tested to verify that it
mets certain ductility and rotational requirements.  And this has nothing
to do with 200x AISC requirements, as I believe such things came into
effect in California after the Northridge quake, where I believe you are
still dealing with 1997 AISC Seismic provisions with supplement #1.

I did not mean to offend in any way or to imply that I know more about
seismic design than you.  While I do believe that there are some
California structural engineerss that think that they know more about
seismic design than everyone else in the country put together (and I am
not implying that you are one) and while I personally feel that such
individuals are likely arrogant smucks, I KNOW that personally the amount
that I know seismically likely is microscopic compared to what many
structural engineers who practice on the West Coast (including California)
know.  I KNOW that while I might feel at times like I know a lot, I still
only have a few grains of sand of structural engineering knowledge in my
hand with a whole beach worth to learn...and it will remain that way until
I die, no matter how much I learn along the way.

HTH,

Scott
Ypsilanti, MI (about as non-seismic as you can get in this country)


On Wed, 16 Jul 2003, Bill Allen wrote:

> Scott-
>
> I don't think you're correct in your assumption with regards to testing.
> Not EVERYTHING has to be tested. I think it depends on things like
> Applicable Building Code, etc. Yes, where the 200x AISC Seismic
> Provisions have been adopted as "law", WFs need to either be
> pre-approved (FEMA 350), proprietary or tested. Of course, testing for
> an individual small project is not realistic. For example, I'm sure I
> could design for R=1 and not have to test anything. Maybe design for R=3
> and just use structural mechanics as someone else has mentioned. Makes
> sense to me.
>
> And, while I'm at it, yes I'm aware of ductility requirements, etc.
> except that they are different for SMRFs and OMFs.
>
> If you have a specific code section you would like to quote (rather than
> vague philosophy), please continue.
>
> I scanned the archives and saw a post from Rick Drake who mentioned a
> limitation of b/t for HSS sections that seem (at least according to him)
> to be highly restrictive. However, in my applications, the load is low
> and TS6x6x3/8" would be O.K. These sections meet the b/t requirements.
>
> Also keep in mind that, here in LA LA land (where earthquakes are
> reality, not academic), we have over 90 building departments, some
> subscribing to the LARUCP (Los Angeles Regional Code Program) but most
> not and, most certainly, every one of them interpreting our shameful,
> antequated Applicable Building Code (2001 UBC which looks an awful lot
> like the 1997 UBC).
>
> And, puleese don't school me on FEMA 350, etc. either. I've been to the
> seminars, worked the examples, set up standards, designed REAL projects,
> submitted them to building departments, received building department
> approvals, and then subjected them to the poor steel fabricators who are
> convinced that I am personally trying to drive them out of business. I
> am not in academia.
>
> The purpose of FEMA 350 is to provide some pre-approved solutions to the
> problems with welded FLANGES of WF sections in moment connects used in
> HIGH SEISMIC REGIONS. I'm not sure what performance problems TS frames
> have experienced nor have I spent a lot of time (like none) reviewing
> the HSS design manual, so I am admittedly weak here. I just thought
> lightly loaded tube frames could skirt the FEMA problem here in
> applications where cantilever columns are not practical (for whatever
> reason).
>
> Regards,
>
> T. William (Bill) Allen, S.E. (CA #2607)
> V/F (949) 248-8588
> San Juan Capistrano, CA
>
>
> :-----Original Message-----
> :From: Scott Maxwell [mailto:smaxwell(--nospam--at)engin.umich.edu]
> :Sent: Wednesday, July 16, 2003 6:16 PM
> :To: seaint(--nospam--at)seaint.org
> :Subject: RE: REFERENCE TO HSS MOMENT CONNECTION
> :
> :
> :Bill:
> :
> :I believe what Ben was trying to point out is that there are
> :no pre-approved HSS moment connections.  The only connections
> :that have been tested and pre-approved for use (i.e. requiring
> :no further testing on your part prior to use) are wide flange
> :beam to wide flange column full moment connections (of certain sizes).
> :
> :You can still use ANY type of connection (at least to my
> :knowledge) of any type of steel members (HSS, WF, etc) BUT you
> :have to have them tested before they are permitted for use.
> :This is also true for WF beam to WF column connections that
> :have members that do not include the WF sizes used in
> :pre-approved/tested connections (i.e. for example, "deep" WF
> :columns have not been pre-approved so you are limited to
> :10x10, 12x12, and 14x14 nominal WF columns, etc).
> :
> :Thus, if you want to use a HSS to HSS moment connection, then
> :you will need to have the connection tested to determine if it
> :meets the minimum requirements for the connection type that
> :you want to use (i.e. ordinary, intermediate, or special
> :moment frames).  These requirements include things like
> :minimum ductility requiremenst and rotation limits (if I
> :recall correctly).
> :
> :HTH,
> :
> :Scott
> :Ypsilanti, MI
> :
> :
> :On Wed, 16 Jul 2003, Bill Allen wrote:
> :
> :> Ben -
> :>
> :> Is this (prohibition of tube frames) just in the LARUCP "sphere of
> :> influence" or is there a specific section in the Applicable Building
> :> Code (in my case, the 2001 UBC) that you can reference specifically
> :> prohibiting the use of tube frames?
> :>
> :> This might turn into a Jeffersonian/Hamiltonian argument: if
> :it's not
> :> specifically excluded, is it allowed or if it's not specifically
> :> allowed is it excluded?
> :>
> :> Thanks,
> :>
> :> T. William (Bill) Allen, S.E. (CA #2607)
> :> V/F (949) 248-8588
> :> San Juan Capistrano, CA
> :>
> :>
> :> :-----Original Message-----
> :> :From: Ben Yousefi [mailto:Ben-Yousefi(--nospam--at)ci.santa-monica.ca.us]
> :> :Sent: Wednesday, July 16, 2003 8:00 AM
> :> :To: seaint(--nospam--at)seaint.org
> :> :Subject: Re: REFERENCE TO HSS MOMENT CONNECTION
> :> :
> :> :
> :> :There is no such thing for seismic design!
> :> :
> :> :Currently there is no approved moment connection type, for :seismic
> :> application, using HSS section. All the tested :connections so far
> :> have been with rolled W sections. Even the :built up boxes are not
> :> approved at this time.
> :> :
> :> :Ben Yousefi, SE
> :> :Santa Monica, CA
> :> :
> :> :>>> dnae(--nospam--at)cox.net 07/15/03 04:24PM >>>
> :> :Hi
> :> :I need reference in the code or AISC or FEMA  for HSS moment
> :> :connection normally it shows full penetration all around the walls
> :> :is there reference to support that to acceptable
> :> :
> :> :Thanks
> :> :Dave
> :> :
> :> :
> :> :
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