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Re: Conv. Constr. one direction

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At 11:13 AM 7/26/99 -0700, you wrote:
>We're reviewing a wood-framed project designed under the 1988 UBC.  In one
>direction, the lateral design was engineered, with shear walls, holdowns,
>etc.
>
>However, in the other direction, where there are long party walls, the
>engineer stated that Conventional Construction criteria were met, so he just
>put in gyp. bd. shear walls.  When we work the loads backwards from his
>calculations, these walls would be overstressed using the loading for his
>designed direction.
>
>My questions:  Was there anything in the code that said you could use
>conventional framing requirements in one direction even if these
>requirements weren't met in the orthagonal direction?  Was/is this the
>standard of care?
>
>Mike Livingston, SE
---------------------------

Mike, the 88 UBC deems that meeting Conv Constr satisfies the code, even
though Dennis and everybody knows that calculations don't necessarily
confirm stresswise equivalency. 

It isn't an engineer's burden to seek out the most stringent of the several
parallel applicable code-given approaches to design and use the one giving
the strongest result; rather the engineer is welcome to use one giving the
least strength, least cost, etc. That is what the code expects.

See Sec 2303(a) in 88UBC, specifically the exception: "...buildings OR
PORTIONS THEREOF which are constructed in accordance with the conventional
framing requirements of Chap 25 of this code are deemed to meet the
requirements of this section." (and thus in effect meet all of Chap 23.)

I would say that if the engineer saw the non-designed direction was going to
comply with conventional, he had no burden to do an engineered design for
that direction.  That is the same "consideration" a plans reviewer makes in
determining whether to send the plans back for more engineering. Even if the
engineer initially calculated lateral loads and then quit doing a calculated
design, the code compliance basis reverts to conventional without prejudice
to the engineer.

The purpose of code conventional provisions is to obviate engineering and to
leave the matter a two-way interaction between builder and inspector. As
such the engineer doesn't have to design and detail Conventional elements
with any of the usual rigor. The code book covers it and the contractor is
bound to both follow code and use accepted trade standards for good and
workmanlike construction, as per his own licensing act (Sec7109-7110)
without reliance on an engineer.

If you're in California and the project is residential as limited therein,
see PE Act section 6737.1, where the Legislature, as SB790 in 1985, enacted
this same principle outside of mere bldg code: only PORTIONS not meeting
conventional need engineering, and it is the job of the bldg official to
call the shot.  See www.dca.ca.gov/pels to read the PE Act.

Not until the 1994 UBC was conventional constr non-engineered usage limited
by occupancy, primarily to residential.

Presuming that the engineer is OK with respect to following code in
engineering the one orthogonal direction only, I don't see where it matters
about standard of care in the same issue.  Standard of care is what others
in like situations generally do as to their permitted discretionary acts,
and if most others have a mistaken impression of the meaning of codes and
laws, a person using a correct interpretation still isn't a violator. One
main purpose of law is to protect persons who comply with it; to declare
what is permitted.

See the Kardon paper on the website I mentioned in an earlier post today for
a very good discussion of your role. Note that a key item is the scope of
what the engineer was "hired to do."  It may be narrower than one assumes,
and it isn't an engineer's role to become the boss of his client and impose
a different scope or the scope a future critic prefers. Also consider that
the code is a scattered hodge-podge of provisions, alternative routes of
compliance, and exceptions, and you should find and be able to "harmonize",
like in the Supreme Court decision I quoted, all its pertinent provisions in
evaluating the code compliance of another person (or of yourself). In other
words you should be able to cite your "authority" (laws, codes, verified
standards of care, etc) for your findings in a way that is inclusive of, and
relates to, all of it. 

Serious business, this finger pointing after the fact.

Charles O. Greenlaw  SE    Sacramento CA 
Member, SEAOC prof practice commmittee (but not speaking for them)