Well, then it’s a damn good guess, sir.
David L. Fisher SE PE
Senior Principal
Fisher and Partners
372 West Ontario
Suite 301
Chicago 60654
312.622.0409 (m)
312.573.1701
312.573.1726 (f)
www.fpse.com
-----Original Message-----
From: Gerard Madden, SE [mailto:gmse4603@gmail.com]
Sent: Wednesday, September 09, 2009 1:18 PM
To: seaint@seaint.org
Subject: Re: Cracks at Bay Bridge Eye Lug
Answer? More like a guestimate
On Wed, Sep 9, 2009 at 10:38 AM, David L. Fisher <dfisher@fpse.com> wrote:
Somehow, I knew Gerard would have the answer on this one.
David L. Fisher SE PE
Senior Principal
Fisher and Partners
372 West Ontario
Suite 301
Chicago 60654
312.622.0409 (m)
312.573.1701
312.573.1726 (f)
-----Original Message-----
From: Gerard Madden, SE [mailto:gmse4603@gmail.com]
Sent: Wednesday, September 09, 2009 12:36 PM
To: seaint@seaint.org
Subject: Re: Cracks at Bay Bridge Eye Lug
I'm betting its a combination of Fatigue and loadings from the construction work that happened this weekend.
The bridge is 72 years old I believe. It's a tension-only pin connection where a crack has happened on the eye part of the plate from the pin edge to the edge of the eye-plate
They use the term I-Bar on the news, but's its really a flat plate (a series of them) with a EYE end (like an eye-bolt) with a pin thru the eye of the sandwiched plates.
-gm
On Wed, Sep 9, 2009 at 9:20 AM, <FSRahbar@aol.com> wrote:
Does anyone know how old this particular connection is?
Farzin S. Rahbar, SE
David C. Weiss Structural Engineer & Associates, Inc.
(818) 227-8040 Ex. 13 Fax: (818) 227-8041
Yes it seems to be an unexplained problem!
Is there a batch of bad connectors from way back when made? Did they
cause this during the current construction? Were there strain gage
monitors on the bridge elements. Did they over rely on the computer
modeling parameters? Is there unexpected settling of foundations? Is
there a now discovered higher risk?
David Merrick, SE of Sacramento
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