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Re: UBC Section 2213.51

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Thanks for responding Jeff,

I have printed up a "procedure" for omrf frame design for use in our office.
Thought about posting it in a message but due to the lack of interest in my
posts (based on yours being the only response) on this issue I probably
won't. Seems everyone is more interested in non technical issues this week
and last.

I was floored by the shotgun approach of this plan checker. It was clear
thru our conversation that he is as befuddled as anyone else and just came
up with a "simple" solution. I checked my frame based on his suggestion and
noooo way am I going there.

Any way, thanks for your insight.

Regards,

Mark

----- Original Message -----
From: Jeff Coronado <jcse(--nospam--at)flash.net>
To: <seaint(--nospam--at)seaint.org>
Sent: Wednesday, October 11, 2000 7:50 AM
Subject: Re: UBC Section 2213.51


> Mark,
>
> It looks like your procedure is sound.  Yes, I do think you have to
> factor 1.4 back into E.
>
> As far as your frustration, I don't think I know anyone who isn't
> frustrated with this code, or for that matter, the general direction
> that the code has been going in over the last few years.
>
> As far as the plan checker is concerned, wow!  This takes "ignorancy
> leads to conservancy" to a whole new level.  That person sure doesn't
> want to have anything built in their jurisdiction.
>
> Good luck.
>
> Jeff Coronado, S.E.
> West Covina, CA
>
>
> Mark D. Baker wrote:
> >
> > > Mark,
> > >
> > > The UBC section you allude to only applies to columns.  The member
sizes
> > > you reference appear to be beams.
> >
> > I realize this applies to columns, I had however applied omega to the
> > lateral load acting on my frame instead of applying omega to the axial
force
> > in the frame column.
> >
> > >
> > > I don't recall having to bump up the size of a column so much because
of
> > > this code provision.  Are you aware that this is a strength expression
> > > and you need to factor your column load capacity by 1.7.
> >
> > Yes, but this brings me to another question: The frame analysis from
which
> > the column axial force is taken, is a result of which load combination?
Am I
> > doing the following correctly:
> >
> > 1. Calculate load to the frame.
> > 2. Use ASD load combination equation 12-9, 12-10 or 12-11 to analyze
frame
> > (note E/1.4).
> > 3. Take column axial load out of analysis results.
> > 4. Check column axial capacity based on section 2213.5.1.
> >
> > Here, I get hung up. The frame analysis was done with E/1.4. Now I have
a
> > column axial load at service level forces to which I'm going to check
> > against ultimate capacity (Psc=1.7FaA) of section 2213.5.1?? I do need
to
> > factor my column axial load by 1.4 prior to checking against Psc, don't
I?
> >
> > >
> > > Since it is the nailer transferring the shear to the frame, don't
> > > understand how the nailer capacity can be less than the design shear.
> > >
> > It can't, don't know what I said to give you that impression.
> >
> > > Hope this helps.
> > >
> > Yes, thanks, it has somewhat but as can be seen above, I am still
confused.
> > I have spent far to long trying to sort this fu$%ing code out and have
just
> > about reached my limit.
> >
> > You might be interested to hear a local building officials opinion on
how to
> > design omrf under 97 code. "Design the entire frame for D+2.8E". Don't
> > divide E/1.4 and don't take any stress increases. He understood I was
> > talking about ASD design for the frame.
> >
> > Regards,
> >
> > Mark
> >
> > > Jeff Coronado, S.E.
> > > West Covina, CA
> > >
> > >
> > > Mark Baker wrote:
> > > >
> > > > The load combinations of section 2213.51 are increasing the size of
my
> > > > ASD OMRF members from W12x35 to W16x57.
> > > >
> > > > This frame is located at the end of a 65' x 40' structure, wood
framed
> > > > with diaphragm @ 26' above fin. flr. The frame is also receiving
load
> > > > from a 26' x 40' open canopy, wood framed.
> > > >
> > > > Section 2213.51 states the exception  "Axial load combination need
not
> > > > exceed max. force that can be transferred to the column by elements
of
> > > > the structure......".
> > > >
> > > > I interpret this to mean I can design the nailer/beam connection
(for
> > > > example) for the applied lateral load (no more, no less) and proceed
> > > > with only meeting load combinations of 1612.3.
> > > >
> > > > If this is true, under what circumstances does one not "cheat the
> > > > code" by taking this exception and instead design for the load
> > > > combinations of 2213.51?
> > > >
> > > > Regards,
> > > > Mark
> > >
> > >
> >
>
>