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RE: Tales of Terror #1: Architects doing engineering

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Chuck,
It did get a rise, but not as seem to think. When checking plans there is a
section of the code that requires the use of rational analysis based on
principle of mechanics. I wrote to the list because, in a sense, I was
frustrated to see so many design to a standard much lower than I do (I use
your 20% philosophy and haven't used Keylat or any other commercial software
in a long time). I don't believe in complicated rigid analysis for
light-framed residential structures and I've voice my opinion as to why many
times on the list.
What bothers me is that the quality of the package, the analysis or the
comments and anger from the developers are not improving as the code
intended. They are simply looking for ways to circumvent the code while
meeting the very minimum requirements that they can. It isn't because the
building official will allow this, it is because the developer believes that
they have a right in a free enterprise system to maximize their profit as
long as they meet the minimum requirements of the code and this includes the
conventional construction crap. However, the unfair part of this is that
there is no disclosure in the state or the US that I know of to inform the
owner of their potential liability related to performance. Why is Southern
California using as little plywood on a home to meet lateral design while
Arizona to Illinois almost sheath the home in entirety? 

Maybe I'm rambling, but I guess I believe that the code establishes a
standard that should be followed. If anything, blame the code writers for
the ambiguity that divides the community (those who believe that they can
follow the Static design without a rigid analysis (2.5Ca) and those that
interpret the code to add the 20% you are talking about by using the
Simplified Static design (3.0Ca). Considering that 99% of designers are not
using RDA in their analysis, there is a definite split as to whether they
should follow the Static design or the Simplified Static design. Both
require the analysis for diaphragm deflection and both require that the
building irregularity be investigated, yet no engineer or architect I've
reviewed has used that rationale. 

Furthermore, when I brought up the example of 1/3,1/3,1/3 split of base
shear - mother nature doesn't know how the loads will end up flowing through
the structure - you are right. However, the code does call for a recognized
rationalization in the code by specifying a principle of mechanics - statics
when designing a horizontal diaphragm. At the very least, the designer
should follow this method. What upsets me more is that this particular
Architect applied his ignorance to design the building - his details were
just a poor and I mean generic and far from representing the existing
condition. It was an assembly line structure based on pushing it in and
pulling it out of design to accommodate the profit of the builder/developer.
I can't plan check as I would design - I understand this, but I can enforce
the plan check agency's interpretation of the code (the building official is
not an engineer in our communities and the cities don't employ engineers).
The final word is left to the plan check agency and the one I work for is as
liberal as each of the others in the area - allow the minimum compliance to
the code.

Finally, seeing a design by an architect that can not demonstrate a basic
understanding of statics is a slap in the face for our profession. I do
resent it and was venting as I have to be accommodating and civil when
discussing it with the architect.

I did receive a call from the developer/owner of the project. He was very
upset that I had new comments on his second submittal and wanted to set up a
meeting at the city. I called him (I have known him for many years) and
refused to have a meeting if his architect or engineer was not at the
meeting. In the phone conversation, he was upset that I indicated the shear
wall was damaged by the protrusion of plumbing in the wall. He claimed that
the plywood was on the other side of the wall. When I told him that I was
referring to the plumbing coming through the mud-sill, he was outraged I did
not specifically mention this. The same argument ensued when he cut through
the plywood above a high load shearwall to run 12-inch diameter ducts for
air conditions from the garage into and exiting the home. Almost 60% of the
shearwall was destroyed above the top plate and he disagreed with me. I
asked him if he considered a drag truss so he did not have to extend the
paneling up to the roof and he did not understand the concept of a shearwall
load path. While I was offering him advise, he believed I was targeting him
because he never hired me to do his projects. While this is true, I did work
with him once but he did not want to pay my price after the first project
and this did not upset me as I never worried about work. I do worry about
construction quality and the finished product that the home owner moves
into, but he only believes I'm in it for the money. I don't think so - or
I'd be working for a large office doing bigger projects. But then, who
believes a guy who is not in this business for the money but happens to
enjoy the challenges and the ability to create our own monoliths?>)

Your Friend,
Dennis

PS. Chuck - you can't get me going any more than Bill Allen can. We don't
have to agree on all issues and have locked horns on our disagreements in
the past, but for both of you and a handful of others I can think of, my
ultimate thoughts are about the engineers I'm debating and my admiration of
them as people. I think at the end of the day, and I think Chuck Greenlaw
would agree, we are all friends who admire each of us immensely. 


Dennis S. Wish, PE


California Professional Engineer

Structural Engineering Consultant

dennis.wish(--nospam--at)verizon.net

http://www.structuralist.net

 


-----Original Message-----
From: chuck utzman [mailto:chuckuc(--nospam--at)pacbell.net] 
Sent: Thursday, July 01, 2004 9:05 PM
To: seaint(--nospam--at)seaint.org
Subject: Re: Tales of Terror #1: Architects doing engineering

Dennis-
I thought I'd probably get a rise out of you on this :o)

I guess the bottom line is that it doesn't really matter how the 
"analysis" is performed as long as the resulting construction is 
adequate to meet the code required loads.  If you model your beam on 
infinitely stiff  supports, the middle one gets more load.  If you hung 
it on 3 rubber bands they would each  carry equal loads.  For typical 
wood framed residential construction I think we're a lot closer to the 
second model than the first.  Testing & the plain language of the code 
confirm this to my satisfaction (up to aspect ratios of 1:6 per Ed 
Diekmann IIRC) .

It's true that "I've been doing  it this way for xx years" & "27 out of 
27 engineers are ignoring the code" might be an adequate defense--as 
long as a rigorous analysis doesn't show that the structure fails to 
meet the code requirements.  Most of the time I just bump up the load 
20% & don't worry about it.  If I think it's important enough I run 
Woodwork's Shearwall program. Keylat is too much work.

The reason engineers ignore the code is that the plan checkers let 
them.  City employees enjoy sovereign immunity.  Do you?  If the local 
jurisdiction has legally adopted  some exception, you are covered. If 
they haven't, it seems like you are obligated to enforce the  UBC as 
written.

As practicing engineers we've all made our individual peace with 
flexible/rigid diaphragm issue.  I confess that it amuses me to 
occasionally revisit the matter because I'm convinced I'm correct (even 
though I'm an M.E./C.E. instead of a real C.E. :o)  I'd hate to see a 
friend get into trouble because he has recently chosen to become a 
windmill operator instead of merely tilting at them as a hobby.

Your friend,
Chuck Utzman, P.E.

P.S. The conference was the 98SEWC  in  S.F. & I may have the 
proceedings on a CD.  The testing was at the U. of Texas IIRC. I know it 
wasn't Ficcadente.  Those tests & my discussions with Ed Diekmann, Dan 
Dolan, & Kelly Cobeen about the matter was plenty enough to convince me, 
YMMV

>  
>



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