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Re: Structural Drawings with PDMS ?

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Daryl,
Thanks for your answer. In any case it is out of topic. By the way we
were very concerned, because, besides the over-grade structural issues,
we have to handle the piling designs, which are resulting in an estimate
of works of some $ 6,000,000. BUT, we have been informed that the
whole industrial project is amounting $ 800,000,000. !
In fact, we are not that worried about optimizing the structures, but
how much these softwares, are friendly with our usual structural design
needs.
Thanks again, and regards.
RL
----- Original Message -----
From: "Daryl Richardson" <h.d.richardson(--nospam--at)shaw.ca>
To: <seaint(--nospam--at)seaint.org>
Sent: Monday, June 07, 2004 7:46 PM
Subject: Re: Structural Drawings with PDMS ?


> Raul,
>
>         It sounds great!  I'm sure they also point out that you can
completely
> optimize the structural and keep up to all design changes as they
> materialize!!  But this is utopian and can not be achieved in reality.
>
>         The best the program can do in reality is perform a code check on
> predetermined sizes; it can not optimize sizes for several practical
reasons,
> mostly financial.
>
>         Because these projects (I'm referring to industrial projects such
as
> refineries and the like) take a long time to design, interest charges are
> accruing on the construction financing, and the product is usually pre
sold
> (including the delivery schedule), there is intense pressure to have the
civil
> and structural work done (actually constructed in the field, not just
designed)
> long before all of the equipment loading is accurately known.  This makes
it
> quite common to "take your best guess and add 30% to all loading (they
later
> reinforce those components found to be under designed during the later
> reviews), particularly when the structural cost is a small fraction of the
> total cost.
>
>         For a real life example, I once worked on a gasoline refinery
which
> required piles (with driving tips and using the heaviest section in the
> Canadian steel handbook) 110 feet long.  At the time these cost about $5
000,00
> each; and when I tried to get better information in order to save a few
piles I
> was informed "Daryl, we have $90,000,000.00 worth of piping materials in
Area
> 20 alone!  We don't care if you do waste a few piles."  This same project
had a
> $500,000.00 per day penalty clause for late completion; they really didn't
care
> if we wasted a few piles or if the structural was 30% over designed!
>
>         That's only for design.  Once the project is completed the
operating
> people begin looking for ways to change and improve and fine tune the
> operation.  This includes things like adding monorails and jib cranes in
> addition to modifications to the piping and to the process itself.  Having
the
> structural completely optimized (read that maxed out) would be counter
> productive.
>
>         Just some thoughts.  Hope they're not too far off topic.
>
> Regards,
>
> H. Daryl Richardson
>
> Rlabbe wrote:
>
> > List,
> >
> > I would like opinions on this issue. Regarding large industrial
engineering
> > jobs where all disciplines are involved, piping, mechanical, HV&C,
> > structures, etc. it is coming a usual procedure to handle all of the
design
> > activities through PDS or PDMS modeling tools. It seems to me, that
these
> > fancy models have been conceived for piping / mechanical lay-out issues.
> > How benefitial is this way of design, from a structural standpoint ? The
> > vendors are usually mentioning steelwork design, as one of the resources
> > availabe. The main and critical structural issues, like special seismic
> > connections,
> > or details, are they well covered ? The out-put, is it proper to check
all
> > these
> > issues ?, etc.etc. Anything about the reinforced concrete structures, in
> > this
> > environement ?
> > Any experience, or case study, or opinion about, would be appreciated.
> >
> > Regards,
> >
> > Raúl Labbé S.E.
> > M.ASCE.
> >
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