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RE: Square notch on wf beams

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The AWS you cite is also in the AISC 13th Edition.  Now to your questions.

 

Is there a procedure of fixing the re-entrant corner? 

There are many procedures depending on the nature of the problem, the position of welds, the stress, dynamic considerations, thermal constraints, etc.  Cracks that appear in air frames of aircraft have traditionally been "fixed" by drilling a hole at the terminus to eliminate a stress riser. 

 

Can I weld a plate over the notch?

You can, but is this an effective solution to the problem?  Further, what is the problem?  If the steel is always in compression, do you need to do anything?

 

Can I provide a weld at the reentrant corner to reduce the built up stresses?

First, what are the built up stresses?  Can they be relieved by applying heat?

 

Being a former iron worker, I can assure you that there are thousands of notches in structural shapes in buildings that have performed well for decades with no problem.  I can also point to notches serving as generation points for cracks that required repair after less than a year. 

 

Read AISC Steel Construction Manual, 13th Ed:

Page 9-15 "Copes, Blocks, and Cuts"

Page 9-16 This shoes examples of how to reinforce a cope if required. 

Page 16.1-92 Beam Copes and Weld Access Holes

Page 16.1-327

Basically, if you terminate the cope with a drilled hole you eliminate inspection requirements and you eliminate the stress riser.  So if you can live with the reduced section, get a mag drill, and drill a 3/4" hole (3/8" radius) at the terminus of the re-entrant corner and it is Miller time!  Actually a good porter or stout is more my preference.

Regards, Harold Sprague




Subject: Square notch on wf beams
Date: Wed, 17 Dec 2008 17:15:36 -0800
From: mbrodrig(--nospam--at)mbrodriguez.com
To: seaint(--nospam--at)seaint.org

I have a situation where a contractor has notched a W10x49 beam.   The inspector on the job informed me that a notch was made.  The notch was a square notch with a sharp re-entrant corner.  This does not meet section 5.17.1 of  AWS D1.1/D1.1M 2004 where it states that “…all beam copes and weld access holes shall be shaped free of notches or sharp reentrant corners …”  The contractor informed me that the notch was made for installation purposes.

 

Is there a procedure of fixing the re-entrant corner? 

Can I weld a plate over the notch?

Can I provide a weld at the reentrant corner to reduce the built up stresses?

 

Thanks in advance for your input.

 

Marlou B. Rodriguez, S.E.

MBRodriguez Engineering, Inc.

2355 Oakland Road, Suite 14

San Jose, CA 95131

Tel: 408-432-4866 x200

Cell: 408-761-5013

email: mbrodrig(--nospam--at)mbrodriguez.com

 



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