Posted on 07/20/2013 9:04:04 AM PDT by NormsRevenge
While broken bolts on the new eastern span of the Bay Bridge are commanding everyone's attention, Caltrans has another problem on its hands - 96 seismic shock absorbers on the western span, some of which began leaking lubricant just three years after they were installed.
The estimated cost of the fix - $13 million.
And, like the brittle bolts on the eastern span, there are questions as to whether Caltrans ordered the right shocks - or dampers, as they are known - in the first place.
The dampers are located between the bridge towers just below the roadway, and are intended to dissipate energy from an earthquake and reduce stress on the structure.
Caltrans installed them in 2004 as part of a $670 million seismic upgrade of the western span and its approaches. Transportation officials expected them to last 20 years.
But by 2007, Caltrans officials say, a dozen of them began leaking.
The number has since grown to 37.
(Excerpt) Read more at sfgate.com ...
Good Herb Island....as far as the best translation Ive been able to find goes.
is there any wonder that there’d be a Good Herb Island in San Francisco Bay?
Nah they didn't need the him on the project. But I am sure the price tag for the structure was close to what such a thing would actually cost, to make it out of gold.
Lowest bidder?
Senator Diane Feinstein and her husband Dick Blum own steel mills in Shanghai.
That is why the democrats ordered the project be done by the Chinese. Its a win—win for the Blums and the communists.
Jerry Brown and former governor Arnold Schwarzenegger also in bed with the chicoms.
Brown is sending a lot of California taxpayer dollars to China as well, he is a penultimate jerk.
And the MSM recently has been praising Brown for solving California’s budget problems, and turning around California. Go figure. A Democrat can do no wrong, apparently.
Big Whoops! You’re right, of course. No coffee yet today. My Dad learned SONAR on TI back in WW II.
Different bridge and project, HT!
There are to bridges connected by an island. This story is about the section that is not being replace. It was built in the 1930’s and I am fairly sure we were not importing parts from china back then.
Naw, I'd guess they're getting excessive piston and cylinder wear from the unexpected daily temperature excursions. Those are big old shock absorbers.
“They could have built a pontoon bridge for half the price and twice as reliable as the monster now standing (but no one knows for how long it will remain doing so).”
So tell us, how would you get up to the level of the tunnel on Yerba Buena Island the feeds onto the western span? That would be some ramp!
You got it right. From the article:
“The original specifications weren’t very clear,” said Bob Schneider, a project manager for Taylor Devices, the North Tonawanda, N.Y., company that supplied the dampers.
Schneider said Caltrans had understated how much bridge movement the dampers would be subjected to on a daily basis from wind, traffic vibrations and temperature changes.
Actually the bolts that are failing were made here in the US. What is vexing to me is that they had them “plated” to protect against corrosion when they knew ( or should have known) that plating causes “hydrogen embrittlement” which makes the bolts susceptible to brittle fracture.
You actually expect FReepers to read an article before commenting? WoW! The Hubris!
I’m 4th gen Bay Area (Oakland). Stationed on TI 60-61. General electronics and RADAR.
It connects Little Africa all the way to Fairyland!
The dampers are not on the new bridge. They are on the old suspension bridge between Yerba Buena island and San Francisco. They are intended to damp out the longitudinal “slamming” motion of one section of the bridge slamming into the neighboring sections during an earthquake. The intent is that when a jarring earthquake is done shaking the bridge, the sections come to a rapid stop rather than continuing to smash each other to smithereens.
To deal with the extra wear and tear, Shuck says, Caltrans is “looking at replacing them in a way that the absorbers don’t have to engage during small movements.”
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Simple fix , elongated bolt holes, soft rubber mount bushings or a linkage system that allows for a few inches of movement... these shocks aren’t supposed to damp every .25” movement because of a breeze , that causes unnecessary wear in a concentrated area.
A vintage motorcycle I have sprung three separate seeping-type leaks when the temperature rose to 105F recently. 60 at night. Both rubber seals and metal-to-metal joints. Now at 95 leaking has stopped. Another bike experienced actual damage from excessive expansion of the metal frame (plastic gas tank split -- I have hogged out the mounting holes on the new tank).
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