] [Thread] [Date] [Author]

["David L. Fisher" <dfisher(--nospam--at)fpse.com>]

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)

 

www.fpse.com

 

 

-----Original Message-----
From: Gerard Madden, SE [mailto:gmse4603(--nospam--at)gmail.com]
Sent: Wednesday, September 09, 2009 12:36 PM
To: seaint(--nospam--at)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(--nospam--at)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

 

In a message dated 9/9/2009 8:49:23 A.M. Pacific Daylight Time, mrkgp.se@gmail.com writes:

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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