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Re: Tales of Terror #1: Architects doing engineering

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Chuck,

I wouldn't say Dennis is wrong. A continuous beam that  spans over two
supports will have a larger reaction at the center support (about 62.5% of
the total load). This model seems appropriate for large diaph. spans (say
40' deep diaph. spanning 250' with intermediate support at half this dist
125'). Now if the span is short relative to the depth of the diaph. then an
even dist. seems reasonable as you have suggested.

Rand



----- Original Message ----- 
From: "chuck utzman" <chuckuc(--nospam--at)pacbell.net>
To: <seaint(--nospam--at)seaint.org>
Sent: Tuesday, June 29, 2004 11:45 AM
Subject: Re: Tales of Terror #1: Architects doing engineering


Dennis-
IMHO the dumb architect has it right  & you persist in doing  it wrong :o)
Every test I'm aware of shows the distribution to be 1/3, 1/3, 1/3. (If
it doesn't  change the wall construction, I sometimes use 1/3, 1/2, 1/3
just to keep plan checkers like you at bay.)

At a SEOC convention in S.F. a few years back, researchers from Texas
IIRC presented their test results from a simple unblocked pitched roof
building.  The uniform load at the top plate distributed itself  1/3,
1/2, 1/3.  Likewise for every reasonably proportioned floor platform.

Chuck Utzman, P.E.

Dennis Wish wrote:

> I started to write this in order to vent my frustration as a contract
> (sub-contract) plan checker who has found that more architects are
> designing the structural elements of high-end custom homes. This is
> upsetting – I’m actually making money as the more errors I find, the
> more time I spend and the more I make hourly. I don’t need to design
> their homes, I only need to plan check them.
>
> Don’t misunderstand, I know a great many architects who became
> engineers and they went through the hard work to prove they were
> capable. But what I am seeing are architects who think they remember
> their statics and strength of materials from forty years ago and
> attempt to apply it today in order to save the cost of hiring an
> engineer. Three or four plan check cycles later, they tend to find
> engineers to help them through the things they don’t understand.
>
> Just one example – I can’t resist this one. The designer (I am
> hesitant to use the title architect) calculates the base shear of a
> fairly rectangular building with three lines of resistance. Rather
> than waste the time to design the distribution of the two diaphragms
> between the three grid lines as simply supported beams, the architect
> applies 1/3 of the total lateral load to each line of shear. Have I
> missed something? I’ve been used to figuring the reactions which
> almost always ends up with 50% of the shear in the middle wall and 25%
> at each end. He would have been better off eliminating the center
> shearwall had it not been for a re-entrant corner and don’t get me
> started on that one.
>
>
>
> What has this world come to when BORPELS (California) has no control
> over architects practicing engineering and the office of the
> Department of Consumer Affairs that licenses Architects will do
> nothing until the damage occurs and the Architect is considered
> potentially negligent (I’ve checked – trust me).
>
>
>
> Politics has reached every segment of our society – I mention
> certification of Framers and find the BIA (Building Industry
> Association) putting me on their black list.
>
>
>
> So, what’s your take on all of this? Should I just retire to
> Southeastern Arizona and become a hermit (with my wife family and dogs)?
>
>
>
> Dennis
>
>
>
>
>       Dennis S. Wish, PE
>
> California Professional Engineer
>
> Structural Engineering Consultant
>
> dennis.wish(--nospam--at)verizon.net <mailto:dennis.wish(--nospam--at)verizon.net>
>
> http://www.structuralist.net <http://www.structuralist.net/>
>
>
>
>
> ---
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