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RE: Mechanical Engineer wants me to stamp his M sheets

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Dang, Conrad.  You have a lot of time on your hands!  LOL?

Terry Weatherby
Weatherby-Reynolds-Fritson
Engineering and Design
Jackson, California
 

From: Conrad Harrison [mailto:sch.tectonic(--nospam--at)bigpond.com] 
Sent: Tuesday, April 01, 2008 11:23 PM
To: seaint(--nospam--at)seaint.org
Subject: RE: Mechanical Engineer wants me to stamp his M sheets

Gerard Madden wrote:

? Just finished a big project for DSA (a division of DGS) who had the
architect sign and seal all 447 sheets of the drawings set, including the 35
structural sheets. ?
<end quote>
It makes sense. The architect as principle designer is responsible for
delegation of work to specialist consultants. If they wanted to they could
design everything themselves. But it would be beneficial to get certain
aspects of the design reviewed by specialists. Evaluating
fitness-for-function against mandated performance criteria is not the same
as design, nor is documentation and presentation the same as design. If I
want to design a structure using 2kPa wind load I can, and the resultant
specification will in most instances be found code compliant because the
code will produce a pressure of around 1kPa or less. There are also other
issues to consider in design, such as economy of fabrication and
construction: there are a multitude of other issues where the minimum size
for a member is larger than that recommended by purely structural
considerations. So design first, code checking last.

The architect as principle designer is responsible for bringing all those
other issues together and deciding on the final specification. By sealing
all the documents the architect is declaring everything has been
coordinated, all issues have been considered, and the whole building is
fit-for-function. They are also declaring a confidence in the SE they
appointed for the structural design. If the architect refuses to sign the
structural drawings, then they must have issues with the competence of the
SE they appointed, in which case another SE needs to be appointed to review
the proposal. The architect should have the competence to read the SE?s
drawings and accept or reject as suitable for their project. The architect?s
prior experience should alert them as to whether the current SE is under or
over sizing: leading to a requirement for the SE to justify or be replaced.

Personally I don?t see why the architect cannot document the entire project,
it would be far more efficient, and they would have done so historically.
The engineers and other sub-consultants are employed to provide design
input, and specialist skills in evaluating sufficiency-of-purpose. Drafters
produce the formal documents, and can produce about 80% of the content
without engineering or architectural input. Designers may present their
ideas as technical drawings but it is the drafter who turns it into a
controlled document. So the architect could employ all drafters in their
office, and doing so would re-integrate a lot of the design content into the
mind of a single design-drafter. Especially more efficient when using layers
and external references in CAD, or the more hi-tech BIM packages. The
drawings are simply a virtual model built on paper, and the engineers and
other designers simply supervise its construction on paper. The division
between specialists is relatively artificial and arbitrary: specializations
increase by the year. So having the principle designer in control of all
documentation and presentation standards has its benefits.

For that matter separate the documentation process from the designer?s
altogether. Traditionally technical drawings were produced to solve
problems: now drawings seem only to exist as a means of presenting
solutions. With documentation becoming an end within itself: rather than a
means to an end. So architects and engineers can both get their documents
produced by an independent drafting service. Forcing the designers to
reconsider the value of drawing as a problem solving tool, and that they
themselves should still be working at a drawing board (or CAD). Also to
further recognize the real value of their services, given that many projects
are simply documentation exercises, in need of technical review. And also
noting that past documentation potentially presents design content more
robust than what modern incomplete codes of practice permit. That is if do
not have experience of past practice, then design purely to the code will
most likely produce something defective: because there are a multitude of
design issues not covered by the codes. So a drafter with 30 years
experience may produce a better solution than a code-cruncher.

So what really matters is that a design proposal is properly documented, and
that such documented proposal has gone through an adequate series of checks
to ensure that the proposal is fit-for-function, sufficient-for-purpose and
ultimately code-compliant. The code issues coming last. Further that there
is a principle designer to address issues not properly addressed with
respect to fabrication and construction, and to properly coordinate and
re-evaluate design changes arising from the need to make the implementation
of the proposal feasible and practical. For a building that person is
usually the architect.

Regards
Conrad Harrison
B.Tech (mfg & mech), MIIE, gradTIEAust
mailto:sch.tectonic(--nospam--at)bigpond.com
Adelaide
South Australia
 


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