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RE: Steel Connection Design Costs

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Charlie 

Having seen both approaches I agree with you that this question does not
lend itself to simple answers.

You are correct to make the point that with either approach it is necessary
that things be done properly.  It is my belief that is harder to do things
properly using the  East-coast approach.  On the West-coast the fabricators
have gotten together and published guides showing the relative costs of
different types of connections.   As a result most West-coast engineers use
these connections which should minimize
shop and field labor.

An Engineer with a well known firm East-coast firm that has done work in
California has stated that the engineer will spend essentially the same
amount of time under both systems if he does the job right.  On the West
coast we spend the time desiging the connections during the CD phase while
on the East-coast the Engineer will spend the time reviewing the
contractors designs.  Remember the Engineer of Record for the building
still shares responsibility for the final connection design even though it
was designed by the Contractor.  Thus if you do the necessary checking of
the design the design fees should be similar so any savings to the Owner
can only result if the Contractor's Engineer can create a cheaper design to
offset the cost of his fees.

On one fast track East -coast project that I worked on, the Engineer of
Record designed the connections since this eliminated the time required to
review the Contractors submission of connection designs which had to be
done before the start of shop drawings.  Any potential saving in
construction cost was less important than the saving in schedule.  In fact
on this project the EOR got an additional fee to design the connections.

The big argument in favor of having the contractor design the connection is
that the fabricator can use the connections that are most efficient for him
to produce.  Some shops seem to like to punch holes all day long and find
angles and bolts cheaper than welding.   Before counting the savings I
would suggest that you compare the errection costs since what is cheapest
for the Fabricator to fabricate may not be the cheapest to errect.  

To the extendt that the savings is tied to a preference for bolting or
welding it would be possible to provide a schedule of acceptable bolted
simple connections that could be used in place of welded simple connections
thus allowing the fabricator to chose the connection that he believes is
the cheapest.  The point being that the percieved cost savings is not
necessarily tied to who designs the connections.

I believe that you will find that the reasons for the different approaches
have more to do with historical circumstances and the relationships between
the various players.   Both systems work not necessarily because they
produce the lowest costs but rather because they result in a system where
costs can be reasonably predicted thus allowing decisions to be made.  

Costs are important but you will find that on most projects the Owners
decision to build or not to build is not greatly influenced by a 10% or
possibly larger variation in the cost of the structural system.  This is
born out by the fact that each time the seismic design forces were
increased there has been great concern expressed about increases in cost
slowing construction.  Based on these concerns ou would expect the
West-coast to be an economically depressed region, yet today most firms
have more work than they can easily handle.


Mark Gilligan



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Message text written by INTERNET:seaint(--nospam--at)seaint.org
>>how much difference would there be in the Steel fabrication budget
>if a fabricator bid the same job each way: once from a West Coast
>E.O.R. with connections provided and once from an East Coast
>E.O.R. with reactions provided?
 
This is a tricky question.
 
I think the best situation from an economy (and a design) standpoint is
somewhere in between the two extremes you mentioned. That is, use the
engineer's knowledge of the structure and design together with the
fabricator's knowledge of how the shop works best and how the building will
go together. Of course, in the real world, that's pie in the sky. So back
to
your question.
 
This is a gut reaction, but I don't think there will be much of a cost
difference between East-coast and West-coast approaches if everything is
done properly. Properly? Here's what I mean.
 
For the East-coast approach, properly means the nature of the framing,
connections and connection design requirements have been clearly defined by
the engineer of record. A few specifics: Are stiffeners required or not?
Can
shear tabs be used or not? Are the actual (or at least reasonable)
reactions
shown on the drawings or is it one of those jobs where the connections
can't
be made to develop the inflated reaction requirements specified arbitrarily
in the contract documents? Economy in this approach is probably inversely
proportional to the number of ambiguous and catch-all statements on the
contarct documents.
 
For the West-coast approach, properly means has the engineer of record
understands how the components of the building will be fabricated and how
the building will go together. A few specifics: Are the connections such
that the building can be fabricated in pieces that are shippable and
erectable? Are the framing and connection details configured to minimize
shop and field labor?
 
The thoughts above are quick and I probably left a lot of the details out.
In the end, I think economy can be had with either system. Economy is
probably more a function of how good the communication is with either
system. I'd be interested to hear what some of the fabricators and other
industry types on this list think.
 
Charlie