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RE: Designing Steel Connections - What Is Required On Drawings?

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Bill,

The practice is very regional for general buildings.  In the Northeast, the
practice is to performance specify the connections.  The connection designer
must be a PE and must be approved by the EOR.  The connection design is let
either directly by the GC or through the steel sub.  In either case the
steel sub works collaboratively with the connection design engineer to
develop the most cost effective connection design.  Often times the
connection designer must submit sample calculations and qualifications that
are used by the EOR to approve the connection designer.  

In the West the tendency is to detail most all of the connections by using
some standard connections.

The fabricators have their own preferences for connections, and they will
vary depending on their equipment and plant layout, and if the fabricators
are erecting the steel or if the erection is contracted out.  The
requirements of the new OSHA Subpart R are not yet law, although they are a
good practice.

The use of A307 bolts as erection bolts is not a bad idea.  The fit up crew
hangs the steel and plumbs the building.  Then the bolt up crew goes through
and replaces all the unmarked A307 bolts with the A325 bolts (if required),
and then the bolts are tensioned (if required).  

If the A325 bolts are "twist offs", they may loose their lubrication prior
to tensioning if they are placed many days before the bolt up crew gets on
the connection.  If that is the case, the tension may not be achieved, but
the end will be snapped off giving the false impression of a properly
tensioned bolt.

Either the performance specification or the complete connection design is
acceptable within the parameters outlined in Section 3.1.2 of the AISC Code
of Standard Practice, March 7, 2000.

Of equal concern is erection stability.  Some subsections of structural
engineering design for erection stability, and get involved with temporary
stability.  Bridges and long span structures (arenas) are designed for
erection stability often by the EOR.  The building industry generally does
not get that involved in erection stability and sequencing. 

As far as what is required by law, the AISC Code of Standard Practice is not
the law, but it infers accepted standard practice.  

Regards,
Harold Sprague


> -----Original Message-----
> From:	Bill Polhemus [SMTP:bpolhem(--nospam--at)swbell.net]
> Sent:	Friday, September 01, 2000 11:30 AM
> To:	structx(--nospam--at)polhemus.cc; seaint(--nospam--at)seaint.org
> Subject:	Designing Steel Connections - What Is Required On Drawings?
> 
> Another question in a similar vein to those I've posted recently.
> 
> The "old practice" in routine (i.e. non-moment resisting) connections was
> to
> simply put the maximum loads needed to be resisted on the drawing, and let
> the
> detailer take care of them, since in theory at least, the detailer "knew"
> the
> preference(s) of the fabricator.
> 
> Then, post-Kansas City--and with the cost of litigation on the
> rise--engineers
> of record began to give more specific information. At least that's the way
> I
> believe I've seen it.
> 
> What is "required"? What are the legal implications?
> 
> I have a set of "go-by" drawings from a client where, for example, a
> connection
> of a W beam to an HSS is shown with a shear plate, and some vague
> instructions
> "3/8" plate weld to column and bolt to beam with 3/4" erection bolts". I
> guess
> you could say that's a "design", but there is no weld size given (my only
> real
> problem with the detail).
> 
> Also, doesn't the term "erection bolts" connote bolts that are "temporary"
> in
> nature? Haven't there been instances of A307 bolts used as "erection
> bolts" for
> example? If so, is this not possibly misleading?
> 
> Any input would be appreciated.
> 


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