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RE: Design of Steel Joists

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In the 13 years that I have been using joists for both floor and roof
construction, I have always selected the joists to be shown on the drawings
and that are expected to be used for construction.  I have never seen a set
of drawings that require the joists to be selected by the joist
manufacturer.  I use the term selected because the "design" of the joist
(i.e. the actual sizes of the chord and web members) are the design of the
joist manufacturer and must meet the requirements of the SJI.

The only exceptions to this are the occasions where non-parallel chord
joists are used or where non-uniform joist loads are required.  In such
cases, a schematic joist elevation is shown detailing the joist
configuration and/or loads so that the selection and design can be performed
by the joist manufacturer.

 
 	Warren S. Foy
Structural Design Manager
The Mason & Hanger Group Inc.
 
300 West Vine Street, Suite 1300
Lexington, KY   40507-1814
voice: 859.252.9980
fax: 859.389.8870
web: http://www.mhgrp.com 




-----Original Message-----
From: Kipp.A.Martin(--nospam--at)mw.com [mailto:Kipp.A.Martin(--nospam--at)mw.com]
Sent: Wednesday, May 23, 2001 11:22 AM
To: seaint(--nospam--at)seaint.org
Subject: Design of Steel Joists


I will admit that it has been 3 or 4 years since I last design a project
that used open web steel joists, but I recently finished a job where they
were used.  I "designed" them as I always had done in the past.

   1.  Using design loads, I determined the loads on the joists and used
the SJI tables to choose a preliminary joist size.
   2.  I put this joist size on the framing plans.
   3.  I added notes to my drawings saying that the joist sizes were for
estimating only and that the joist manufacturer was to design the joist.
   4.  I provided the loads and deflection criteria for the joist design.
   5.  I stated that the joist design calcs must be stamped by a PE
licensed to practice in the state the project was located in.

Now that we are in construction, the joist mfr. is refusing to "design" the
joist  They will only provide calcs that show that the joist size indicated
on the framing plans meets the load capacity stated in the SJI tables.  I
asked a co-worker about this and he stated that he had never been able to
get a joist mfr. to do the design.  Has the standard practice changed that
much in such a short time?  I used steel joist on many projects in the
early and mid 90's and always presented the information described above.  I
never once had a joist mfr. refuse to provide design calcs and to pick the
joist.  What is standard practice now?

--Kipp Martin, S. E.\
  Portland, Oregon
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