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RE: W Shape Field Cope

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"Certify".  I love that word.  I'm always being asked to "certify" some
contractor screw-up or another.  But I digress..

Without knowledge of your exact situation, I will agree with you that the
modified section is probably OK with some qualifications:
- Is the beam subject to repetitive or vibrating loads?  You're describing
pretty severe stress concentration points, which could cause fatigue cracks
on the tension flange.
- Is the beam laterally braced?  The section is no longer doubly
symmetrical, and will be more susceptible to torsion and lateral-torsional
buckling.
- What is the condition of the cut?  With a skilled worker and adequate
equipment, the only major heat build-up is at the point where the cut
started - at the edge of the flange.  This location will have a minimal
effect on the remaining section.  There is, however, localized heat effect
all along the edge of the cut which increases in inverse proportion to the
skill of the worker.  If the edge of the cut is ragged, then assume that
you've lost additional steel.

---
Jason Kilgore
Leigh & O'Kane, LLC
Kansas City, Missouri
________________________________________
From: CanitzCF(--nospam--at)aol.com [mailto:CanitzCF(--nospam--at)aol.com] 
Sent: Wednesday, May 05, 2004 6:09 PM
To: seaint(--nospam--at)seaint.org
Subject: W Shape Field Cope

A steel fabricator has a situation where he is required by the project SEOR
to certify that a simple span W14x90 beam has not become structurally
deficient due to his field crew removing 2"x3" notches from the top and
bottom flanges along its length at 16"o.c. The notches occur at only one
side of the web and occurred via torch cutting.

I determined the modified member's geometric properties and it's still OK
(the CD's required only a W14x53). The SEOR is concerned about the high
temperature required to remove the notches from the 3/4" thick flanges. The
beam's sweep and camber are within AISC spec tolerances.

Since no distortion is visible, can that be considered sufficient evidence
that the beam (A 992) is still adequate or is lab testing of a coupon
required? Are in-situ tests available that would apply in this situation?

TIA,
Charles Canitz
Annapolis, MD



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