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Re: We're Not Getting Older, We're Getting DUMBER [WAS: Any Young Engineers Out There?]

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Well, I'm not the person to be discussing steel high rise design and construction (which is what I'm referring to), but my understanding is that the Northridge eq. of 1994 brought to light a very serious problem with the welded connections of moment frames in high rises that had not been recognized before that.  It also caused a reexamination of some buildings that had been thought to survive the 1989 Loma Prieta eq. well, and found that they in fact had been damaged but the damage was hidden by fireproofing. 

Again, I'm not an expert in this area of structural engineering, but this discovery caused a *huge* reexamination of the whole design, detailing, and construction (meaning welding) of steel moment frames because the actual State of the Art of such construction had been found to be faulty.  I.e., the emperor has no clothes.  A multimillion dollar, multiyear crash research project ensued, with major changes to the design and construction methodology. 

In the words, those buildings had *not* been designed to "much earlier codes," but rather to the current codes of the time.

Anyone else with more understanding of this situation listening in?

Ralph Hueston Kratz, S.E.
Richmond CA USA

In a message dated 1/30/06 3:22:24 PM, mailbox(--nospam--at)sgeconsulting.com writes:
Ralph,
But weren't the structures affected/damaged by the Loma Prieta earthquake mostly designed to much earlier codes?  By the same token, many similar structures - again, designed by earlier codes, had successfully survived.
FAIK, our state of knowledge was proven to be lacking on January 17, 1994 and even one year later, in Kobe... 
Steve Gordin SE
Irvine CA

 

----- Original Message -----
From: Rhkratzse(--nospam--at)aol.com
To: BPolhemus(--nospam--at)wje.com ; seaint(--nospam--at)seaint.org
Sent: Monday, January 30, 2006 2:57 PM
Subject: Re: We're Not Getting Older, We're Getting DUMBER [WAS: Any Young Engineers Out There?]

Yes, detailing in the larger sense.  As you probably know connection details are designed & drawn by the design engineer in this area, because they're an essential part of the structural adequacy of the building when push comes to shove. 

In any case such details are governed by codes and those codes must continue to include the current state of knowledge.   Our state of knowledge was found to be sorely lacking on that October 1989 afternoon.

Ralph

In a message dated 1/30/06 2:53:10 PM, BPolhemus(--nospam--at)wje.com writes:

Good point, but isn’t this more a “detailing issue?”

 

From: Rhkratzse(--nospam--at)aol.com [mailto:Rhkratzse(--nospam--at)aol.com]
Sent: Monday, January 30, 2006 4:28 PM
To: Polhemus, Bill; seaint(--nospam--at)seaint.org
Subject: Re: We're Not Getting Older, We're Getting DUMBER [WAS: Any Young Engineers Out There?]

 
In a message dated 1/30/06 12:27:06 PM, BPolhemus(--nospam--at)wje.com writes:


Steel designers have been happily using the 1989 ASD-based MSC for more than fifteen years now, and buildings don’t appear to be falling down of themselves due to inadequate design.

Bill, you're showing that you're not in Loma Prieta (earthquake) country.
Ralph