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RE: STEEL: Lateral Support for Open-Web Steel Joists

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Bill,
 
I've had to deal with this type of thing before.  BEFORE you do ANY work on the addition, have a meeting with the owner and plainly tell them that the posted load is incorrect (make sure it is first) and they cannot load it up to that magnitude.  Ask them if they would like you to determine what the REAL capacity of the system is OR if they want you to determine a retrofit solution to bump it up to the rated capacity (if this is possible -- might be very costly).  If they don't want you to do anything with it, then tell them that you will design the NEW bays to be independently supported (including against lateral ... do you guys have "interior" lateral in Texas?).
 
In regards to WHO you should inform regarding the existing system, check with your licensing board first:  Is it enough to simply alert the owner or does Texas law require you to inform the Building Official (or someone else) as well?  Does the existing system show obvious signs of distress?  If so then anyone and everyone should be notified if the owner refuses to take action (I can't imagine they'd do this).  If the system does NOT show signs of impending failure, perhaps it is enough to simply notify the owner, IN WRITING, that the rated load MUST be changed.  Be careful, though, because whistleblowing can also backfire if it is not done responsibly.  I have a very good Canadian book on engineering ethics entitled "Canadian Professional Engineering Practice & Ethics" (Gordon Andrews, 1992) in which he states:  "A whistleblower must also be aware that the process may involve public exposure and scrutiny of the engineer and may place his or her career in jeopardy. Therefore, whistleblowing is not an act that should be entered into casually, unknowingly or wantonly."  BEST course of action is to seek the opinion of your licensing board.
 
I would be very curious to see other opinions of action.
 
Regards,
Dave K. Adams, S.E.
Lane Engineers, Inc.
Tulare, CA
 
 
 
-----Original Message-----
From: Bill Polhemus [mailto:bill(--nospam--at)polhemus.cc]
Sent: Wednesday, August 04, 2004 2:00 PM
To: seaint(--nospam--at)seaint.org
Subject: STEEL: Lateral Support for Open-Web Steel Joists

Greetings.

 

I have a job that requires adding on a couple of bays to a mezzanine level in an auto parts supply warehouse. The existing mezzanine level has steel bar grating supported on K-series steel joists. The real kicker is that the floor is rated (sign is posted) at 200 psf!

 

Yet the bar grating is attached to the top chords of the joists using typical “saddle clips” (e.g. http://tinyurl.com/6gkdp, illustration at upper left), which IMO will not provide adequate bracing against lateral torsional buckling of the joists under service load. Further, the bridging provided for the K-joists appears to be the standard for construction phasing before a solid deck is put down.

 

First, am I misinformed about the ability of the bar grating with only saddle clips to brace the joists? Of course the owner would say “hey, it’s worked this way for several years, never had a single problem yet! And will want me to put into the new addition exactly what is already there.

 

Second, what would be best: Use K-joists still, but make sure that the joist supplier puts adequate cross-bridging to assume there is no lateral torsional buckling problem? Or use wide-flange girders? I’m tending toward the first option because I could probably quietly slip it by without the owner’s curiosity being piqued.

 

Finally, what is my ethical responsibility with regard to the joist-supported floors which (if my assessment is correct) are not adequate for the posted load? This place is actually within the city limits of a small, well-to-do south Texas town that actually has a building official. Do I need to bring this up to the owner and inform the building official (thus possibly incurring wrath?)

 

This business is a high-profile outfit. I wouldn’t be surprised, in fact, if the building official didn’t choose to look the other way even if I did complain.

 

Sheesh.