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RE: IRC and Plan Reviewers

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Joe,

The term "irregular" means something completely different for WIND than
it does for SEISMIC (read the commentary at the end of ASCE 7) and it
sounds like you recognize that.  However, even a completely REGULAR
building MUST have a complete lateral force resisting load path and the
conventional construction provisions attempt to set limitations to what
a non-licensed designer can and cannot do.

1997 UBC:
Here in California, we are the only Bozos still using this antiquated
Code (as far as I know), therefore anything listed in there pertaining
to Zones 2B and LESS really are non-issues (except to provide a base to
build other detailing requirements upon). I believe Section 2320.4.4 is
misleading because the BODY of Section 2320.4 gives specific directions
on how to lay out your braced wall lines. There are even special
directions for high wind areas, so clearly the layout of braced wall
lines must also apply to high wind areas (Zone 0). The layout of braced
wall lines is intended to allow for some semblance of continuity within
the building industry at attempting to at least provide SOME sort of
lateral force resisting system, which MUST be effective for BOTH seismic
and wind, regardless of zone or speed/exposure. Specific detailing
requirements will differ in high seismic zones, but the need for some
type of LFRS is obvious.

NOW, that being said, there are three things that a "designer" needs to
consider when deciding whether to engineer the whole damn thing or
whether to take advantage of the prescriptive provisions: (1) Can I
identify a braced wall line layout that meets Section 2320.4? (2) Do the
braced wall panels within my braced wall lines meet the requirements of
Section 2320.11.3 AND Table 23-IV-C-1? (3) In high seismic zones, does
my building have any of the unusual shapes identified in Section
2320.5.4?  I typically find that MOST custom homes will fail BOTH Items
1 & 2 in some respects, therefore Item 3 winds up being looked at anyway
when the engineer goes through their design of the LFRS and attached
elements.

I think this is just a partial-answer to your question, but I need to
eat lunch now.  I'm hungry.

Dave




-----Original Message-----
From: Joe Grill [mailto:jgrill(--nospam--at)swiaz.com] 
Sent: Tuesday, January 18, 2005 7:42 AM
To: seaint(--nospam--at)seaint.org
Subject: RE: IRC and Plan Reviewers


Dennis and Dave,

Part of the problem that I am having is where the line is for low
seismic areas but with substantial wind.  The irregularities referenced
in UBC 2320.5.4 only come in to play in seismic zone 3 (section
2320.4.4).

Now if we move on to the IBC. Section 2308.2(7) limits irregular
structures only in categories D or E, therefore a "designer" in category
C isn't required to look at those definitions of irregular.

Now look at the IRC.  The "irregular" limitations are listed in the
seismic provisions in section R301.2.2.2.2.  A category C structure
would apply with the exceptions of one and two family dwellings.  Again,
a "designer" wouldn't be required to go there.

J. Grill

Joseph R. Grill, P.E. (Structural)
Shephard - Wesnitzer, Inc.
Civil Engineering and Surveying
1146 W. Hwy 89A Suite B
Sedona, AZ  86340
PHONE (928) 282-1061
FAX (928) 282-2058
jgrill(--nospam--at)swiaz.com
 


-----Original Message-----
From: Dennis S. Wish, PE [mailto:dennis.wish(--nospam--at)verizon.net] 
Sent: Monday, January 17, 2005 8:30 PM
To: seaint(--nospam--at)seaint.org
Subject: Re: IRC and Plan Reviewers

Dave,
You are right on and I appreciate everything you said in your reply. The

"line" that the code refers to is still somewhat ambiguous and is based 
on a determination of building irregularities that are referenced in the

code. Section 2320.5.4 of the 97 UBC starts to define Unusual shaped 
buildings and their compliance to conventional construction or 
full-compliance. The final determination is allowed to be done by the 
building official and if he has no real background in engineering or 
architecture, then he might misinterpret the compliance criteria. Plan 
irregularities are defined in Table 16-M of the 97 UBC and some of these

are also difficult to interpret.

Dave hit on one point that I think is important. In smaller communities 
such as our desert communities, the building official is under 
tremendous stress by the developers who plead their case (or actually 
threaten) the city council to allow conventional construction to be 
allowed or they will be forced to move into another community that would

allow it. This is a political move that occurs mostly in communities 
that are new and plan a proportion of their building for affordable 
lower income housing. The trouble continues when the community evolves 
into a more affluent community and the developer uses the argument that 
the city allowed their prescriptive design in the past and therefore 
needs to allow it in the future. Thus, more affluent people get the 
shaft as they are buying new homes that are not designed or building to 
a better performing standard in a community where their cost to rebuild 
or repair increases without their knowledge - only so the developer can 
maximize their profits at the expense of the home buyer who does not 
know that there is a difference or that the developer chooses to use the

least materials and the least restrictive code to maximize his profits.

Thanks Dave, it is finally good to see others wake up to the need for 
some responsible determination as to where and when the IRC is 
applicable to be used in new construction.

Dennis


Dave Adams wrote:

> Joe,
> The frontline in the battle between "conventional construction" and
> "engineered-design" is clear. The problem is not that it's difficult 
> to tell where that line is, the problem is that too many building 
> officials are under a lot of pressure to keep residential plan reviews

> "short-n-sweet", so they miss a lot when they give the plans a quick 
> pass-over to determine if anything needs to be engineered. It's 
> unfortunate, but that's what happens. The ICC "Building Plans 
> Examiner" certification exam has nothing (or very, very little) on 
> conventional construction ... or anything structural for that matter 
> ... and it really needs to be changed. I currently hold such 
> certification, which is quite comprehensive on fire/life-safety 
> issues, but I do remember extremely little on the structural portions 
> of the Code.
> I presented a paper at the 2002 Structural Engineers of Southern 
> California conference entitled, "Making Responsible Decisions 
> Regarding Conventional Construction and Engineered Design for 
> Wood-Framed Structures" that you might find helpful. It's based on the

> 1997 UBC, but the principles would also apply to the IRC (for the most

> part, I believe). Let me know if you would like a copy ... e-mail me 
> PRIVATELY. I would imagine that Dennis Wish (a subscriber to the list)

> would have some resources to recommend or pass along as well.
> Regards,
> Dave K. Adams, S.E.
> *Lane Engineers, Inc.*
> Tulare, CA
> E-mail: davea(--nospam--at)laneengineers.com <mailto:davea(--nospam--at)laneengineers.com>
>
> -----Original Message-----
> *From:* Joe Grill [mailto:jgrill(--nospam--at)swiaz.com]
> *Sent:* Monday, January 17, 2005 12:21 PM
> *To:* seaint
> *Subject:* IRC and Plan Reviewers
>
> I have a question to kind of continue our latest discussion. Actually,
> it may be somewhat of a request.
>
>     It has seemed to me that where some of the problem comes from (in
>     the battle between engineers and plan reviewers regarding IRC and
>     IBC) is that there aren't guidelines indicating when conventional
>     framing provisions should stop and an engineered design should
>     begin. Are there any of you out there working within a
>     jurisdiction where the jurisdiction has made that determination
>     for their area? If so, have they put it in a statute or some sort
>     of directive, basically anything like a hard copy? I would like to
>     gather some information if it is out there to take to my local
>     town and county plan reviewers as some sort of ammunition to begin
>     a discussion on this topic. I would rather go in NOT like the lone
>     ranger among the engineering community on this matter.
>
>     Thanks
>
>     J. Grill
>
>     Joseph R. Grill, P.E. (Structural)
>
>     Shephard - Wesnitzer, Inc.
>
>     Civil Engineering and Surveying
>
>     1146 W. Hwy 89A Suite B
>
>     Sedona, AZ 86340
>
>     PHONE (928) 282-1061
>
>     FAX (928) 282-2058
>
>     *jgrill(--nospam--at)swiaz.com*
>


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