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RE: electronic data exchange

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Mark,

I think the issue is bigger than that - the way this is headed is that a
fabricator could take your computer model as the basis for their detailing.
In the northeast it's customary to performance spec the connection design.
If I understand it correctly, with EDI a detailer could take a RAM model,
input it into their detailing software, and the framing layout and reactions
would be imported automatically.  The detailing software takes those
reactions and automatically chooses connections.

If a stick on a CADD file drawn a couple of inches out of scale is a
problem, imagine a beam modeled without outriggers and other miscellaneous
loads that you've checked by hand afterward.  An incorrect reaction in the
model leads to bad info to the detailer, leads to an underdesigned
connection. 

-----Original Message-----
From: Mark Gilligan [mailto:MarkKGilligan(--nospam--at)compuserve.com]
Sent: Thursday, July 04, 2002 2:42 AM
To: seaint(--nospam--at)seaint.org
Subject: RE: electronic data exchange


Scott

Has anybody given some thought to some of the real difficulties that will
occur when the Engineer is asked to provide the Contractor with his CAD
files so that the Contractor can automate the preparation of shop drawings?

In todays structural office I believe you will find that the electronic
files are not as exact as the paper plots imply.   You will find things not
on the right layers and the member locations may not be within a couple of
inches of where they belong.  If we are to change this, drafting costs will
go up and the Engineers will need to spend considerable more time checking
the CAD files.  There are some real reasons why disclaimers are commonly
attached to CAD file provided to the Contractor.

As long as the paper drawings are the governing version, you will find that
there will be instances where it is necessary to draw a member out of scale
in order to make it readable.

A reality is that Architects and Owners make many changes during a project.
 In many cases where the change is small the Engineer may decide to revise
a dimension or two but not redraw the member.  In quite a few instances it
would probably be cheaper to start the drawing over rather than attempt to
make many small changes.

In those cases where the CAD files have been used to define the member
location you will find that it cost the Engineer considerably more than for
a normal project.  Until these issues are resolved I believe that the
primary use for electronic data interchange will be to transfer data from
the detailer to the fabricator.


Mark Gilligan.

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