Posted on 05/06/2013 8:01:34 PM PDT by NormsRevenge
OAKLAND — Strategically positioned high above the water, in a narrow crawl space between the new Bay Bridge deck and the top of its big pier east of the tower, instruments are listening for the sounds of cracking inside steel anchor rods.
Caltrans placed 10 acoustic emission sensors on select rods in early April after some of the massive bolts -- 3 inches in diameter and 17 to 24 feet long -- snapped and triggered widespread worry about the replacement eastern span's seismic safety.
The instrument records the energy produced when a crack initiates, spreads or moves within the rod, said Caltrans materials engineer Bahjat Bagher, who showed off the testing late Friday. But so far, the rods being tested are quiet, a great relief to the agency.
If the bolts -- fabricated in 2010, two years after the 32 bolts that broke -- were also faulty and had to be replaced, the cost to make the $6.4 billion bridge safe for motorists would rise, and Caltrans would face an even greater hurdle to opening the bridge on time.
A second test for hardness is also showing favorable results, although a third saltwater corrosion test is still to come.
"We are pretty confident that we don't have an immediate failure issue with these bolts, but we want to have a strong level of confidence over the long-term," said Toll Bridge Program Manager Tony Anziano.
It's small a piece of good news amid mounting concerns about the $6.4 billion span's ability to withstand the next big earthquake. The long, hefty anchor rods tie the bridge deck and pier columns to the shear keys and bearings that help control sway and uplift during a quake.
(Excerpt) Read more at mercurynews.com ...
It won’t sway like the Tacoma bridge.. but , man,, them bolts all start popping in a big one.. that ting is gonna be an E ticket ride and then some.
A broken anchor rod rises up next to still-tensioned rods on a shear key on the new Bay Bridge Friday afternoon May 3, 2013. Caltrans showed off the rods and some of the techniques they are using to monitor and test other installed anchor rods as they design a fix for the compromised hardware. (Karl Mondon/Bay Area News Group)
The new bridge is way over budget and is defective.
Thanks again, Union workers.
Surprising to me they look just like nuts and bolts I might tighten or loosen with my 1/2 inch drive socket set.
I can not tell which one is broken.
I’d just guess that the one closest to the camera is the bad one — look at how the nut isn’t quite screwed down all the way compared to the nuts on the other “still-tensioned” rods.
I tap my anchor bolts with a small sledge hammer, they make a unique sound when the threads are pulled or the bolts are fractured, My anchor bolts are about 1 1/2’ diameter. They anchor tall silos.
I remember when Oldsmobile tried converting a gas engine to a diesel, we mechanics would literally pull the rocker covers off, tap each head bolt and often they would just pop up with a thunk, all it took was a hammer tap. Too much compression in a diesel for gasoline engine sized head bolts.
Yes I see it now. I think you are right.
Look closely at the bolt in the center of the picture frame, look down to where it sits on the washer. Notice that it doesn'y look like any of the other nut/washer pairs visible. A portion of the nut facing the washer is visible and appears to be conical and extends a bit above the washer. That is only possible if there is no tension in the rod, which means the nut was not torqued down, or the rod has broken in two.
Regards,
GtG
Maybe union workers, maybe cheap contractors buying low quality material. Maybe both. It’s all a racket.
City I live in has the worst WORST streets in the nation. A “resurface” lasts about 7 months, then starts to sag and crack. Clearly it’s not just the workers..the paving gunk looks like molasses. Thing is, it doesn’t matter whose fault it is, the contractors and tradesmen are always busy and the taxpayers get soaked. So soaked, the city decided to cut the police force and NOT answer any property crime calls.
Ya see, in earthquake country, they want their bridges to collapse cleanly, so there’s no twisted mess afterward, like last time.....
Yup. Enlarge thephot and note the distance from the nt to the Lok Tite. That rod has snapped and they backed off the nut.
Wow. One and a half FEET? Those must be some damn big silos.
;)
They built the bridge because the old one “wasn’t safe” in an earthquake. $6.4 Billion and we are right back where we started, almost. We still have to pay off the $6.4 billion!
SF is a big union town and this project is 100% union builders.
You can be sure they cut the usual corners and skimmed their usual cut off of the top, resulting in substandard materials and labor.
They even have a program to rehabilitate criminals by giving them jobs working on the bridge. Yeah, they aren’t doing the advanced stuff, but that should be a hint that they will hire not the best, but who will be the most “diverse”
Affirmative Action and sub-standard materials on a bridge project. No thanks.
A new bridge and bolts are already breaking? I would take a different bridge.
Where were the bolts made? The same factory producing the made-in-China crap hardware sold at the big-box stores? You can easily snap the head off those screws by hand without any power tool.
the broken one is the one in the foreground, where the nut is not seated closely to the socket, all the others are seated in the sockets.
While that affair was being talked about a CHP officer called in. He claimed to have arrested 2 fellows in a stolen car, who were high as a kite on heroin. That in and of itself wasn't particularly odd. It was what they did for a living that he was concerned about. One fellow was a metal worker and the other was welder both workers on the Bay Bridge.
He took them in, booked them and went about his business. He said he checked in about them some weeks later. You guessed it they were back at work on the Bay Bridge and most likley still using heroin. They apparently got a slap on the wrist and the union helped them retain their jobs.
God help anyone caught on that eastern span during a good shaker. The stage is set for a potentially catastrophic failure with substantial loss of life depending on the time of day. To add insult to injury it was also brought out that corners were cut in the casting of the concrete for the pilings as in using substandard concrete etc.
There already have been small news stories surfacing now and then about Cal-Trans safety inspectors falsifying inspection reports but those seem to disappear quickly. That bridge has the record of being the longest public works project in the history of California.
I guess if you end up driving that span regularly it might be wise to carry a life preserver and something to aid your self in cutting your way out of your car if you survive the drop into the bay.
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