Bay Bridge - We'll fix it better this time
Bay Bridge - We'll fix it better this time
(OP)
I haven't really spent too much time trying to figure this out, and very likely the picture is wrong
http://ww w.sfgate.c om/cgi-bin /object/ar ticle?f=/c /a/2009/10 /29/MNLR1A C568.DTL&a mp;object= %2Fc%2Fpic tures%2F20 09%2F10%2F 28%2Fba-br idge1029_g r_SFCG1256 780933.jpg
but can anybody say "Holy indeterminate load path Batman!"
Doesn't this clap-trap add significant resistance to the pin joint's ability to rotate?
Doesn't that introduce shear and moment loading into the eye bars (that they probably weren't designed to deal with)?
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but can anybody say "Holy indeterminate load path Batman!"
Doesn't this clap-trap add significant resistance to the pin joint's ability to rotate?
Doesn't that introduce shear and moment loading into the eye bars (that they probably weren't designed to deal with)?





RE: Bay Bridge - We'll fix it better this time
RE: Bay Bridge - We'll fix it better this time
RE: Bay Bridge - We'll fix it better this time
RE: Bay Bridge - We'll fix it better this time
Is there some reason they couldn't just replace the cracked eye-bar?
Mike Halloran
Pembroke Pines, FL, USA
RE: Bay Bridge - We'll fix it better this time
It's still an ugly repair of an ugly band-aid.
It can't be the first eyebar ever to crack.
Has anyone ever done it better?
Temporarily take the load off a cracked eyebar?
Without welding to adjacent eyebars?
Mike Halloran
Pembroke Pines, FL, USA
RE: Bay Bridge - We'll fix it better this time
Hg
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RE: Bay Bridge - We'll fix it better this time
Mills don't inventory anything anymore. Every run is to-order and done just-in-time (or just a bit late).
RE: Bay Bridge - We'll fix it better this time
Hg
Eng-Tips policies: FAQ731-376: Eng-Tips.com Forum Policies
RE: Bay Bridge - We'll fix it better this time
RE: Bay Bridge - We'll fix it better this time
Bridges have been built with eyebars long before field welding was an option. So how were they replaced?
They seem to always take the same shape; a circular eye with smallish fillets between the eye and the bar proper, instead of the gradual taper in section that one might expect based solely on stress considerations. From that standpoint, eyebar ends in profile should look like swaged cable terminations. So why don't they?
The relative size of the fillets suggests that perhaps, in days gone by, the way to take the load off a given bar was to support its neighbors by paired rounds tied to each other across the fillets, and tied to the other, far distant, neighbor, by long chains or cables with turnbuckles to take up the tension.
Maybe they need to find some really, really old bridgebuilders, or a really, really old book.
Mike Halloran
Pembroke Pines, FL, USA
RE: Bay Bridge - We'll fix it better this time
I hadn't seen this picture of the crack before:
RE: Bay Bridge - We'll fix it better this time
RE: Bay Bridge - We'll fix it better this time
With my most recent eyebar experience, they were located such that they could all be pulled off and replaced. No one was trying to preserve a joint while replacing a single bar. And, by the way, the decades-old retrofits that had been in place to strengthen the old eyebars looked mighty like the 4-rod repair that failed on the Bay Bridge.
There was a project where they recabled a small suspension bridge. That was a very, very serious undertaking.
One more thing--don't read too much into the shape of the eye. It could be as much an artefact of the fabrication process as a well-thought design reflecting stresses or rehab avenues.
Hg
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RE: Bay Bridge - We'll fix it better this time
Closing a bridge carrying 300,000 cars a day (each way) will do a lot to the congestion on the other Bay Area bridges. I haven't seen it mentioned above, but only a "temporary" is warranted.
The "permanent" fix is 100 or so feet to the north.