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Bay Bridge inspections: busted bolts
SFGate.com ^ | 3/27/13 | Phillip Matier and Andrew Ross

Posted on 03/27/2013 9:25:11 AM PDT by NormsRevenge

At least 30 of the giant bolts that hold together the new, $6.4 billion eastern span of the Bay Bridge have snapped.

As a result, Caltrans is considering replacing all 288 of the bolts on the new bridge before it opens, The Chronicle has learned.

Caltrans insists the new span is safe and that plans to open it the day after Labor Day are still on track.

However, officials say it's too early to determine how long it will take to fix the problem - or the cost.

Toll Bridge Program Manager Tony Anziano said engineers are "pretty confident" the problem with the bolts is not a design issue or a construction problem but related to the quality of the steel bolts themselves.

"This isn't exotic - this isn't some wild issue," Anziano said.

Unlike the Chinese-built deck sections, the bolts - some as long 17 as feet - were produced in the United States.

"It appears to be a type of materials problem - the presence of hydrogen in the metal," he said. The hydrogen makes the metal brittle.

(Excerpt) Read more at sfgate.com ...


TOPICS: News/Current Events; US: California
KEYWORDS: baybridge; bolts; busted; caltrans; inspections; madeinchina
US made bolts,, 17 footers..

This bridge is supposed to take an 8.5 or such.. we'll see soon enough if the Ring of Fire pops one off here..

1 posted on 03/27/2013 9:25:11 AM PDT by NormsRevenge
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To: NormsRevenge

These seventeen foot long bolts were NOT tested prior to installation?

What’s that smell I smell?


2 posted on 03/27/2013 9:32:39 AM PDT by rockinqsranch (Dems, Libs, Socialists, call 'em what you will, they ALL have fairies livin' in their trees.)
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To: NormsRevenge

I once met a guy who sold nuts and bolts.

We discussed them for maybe a couple of hours. The markings, quality, the ones used for extreme duty etc. Far more interesting than one might think.

Unfortunately that was over 40 years ago and I don’t remember much. I do remember he said there are a lot of injuries caused by people replacing the nut which holds lawn mower blades on. He said they sometimes just use mild steel nuts or bolts or whatever they are.


3 posted on 03/27/2013 9:34:28 AM PDT by yarddog (Truth, Justice, and what was once the American Way.)
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To: NormsRevenge
the bolts - some as long 17 as feet - were produced in the United States.

"It appears to be a type of materials problem - the presence of hydrogen in the metal," he said. The hydrogen makes the metal brittle.

I'm curious what is the origin of steel that went into those bolts? Does the "produced in the US" tag only mean that they were machined here?

4 posted on 03/27/2013 9:36:04 AM PDT by Greysard
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To: NormsRevenge

Recall that government presumes that it is competent to command a monopoly on bridge certification and inspection. If a private company had this gross failure of inspection and maintenance, the very same government officials would be rushing in front of the cameras to denounce this laxity and to tell the public how government is protecting them.


5 posted on 03/27/2013 9:36:58 AM PDT by theBuckwheat
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To: NormsRevenge
Anziano downplayed the latest construction problem, saying, "I'd be very surprised if you didn't look at any large structural project that used fasteners and didn't have an issue like that. "That's why you have inspections," he said. ___________________________________________________________________________________________________________________________________________________________________

Doesn't seem very concerned, does he? Why can't they do their QC and test the parts before installation. Disclaimer- I am no engineer.

6 posted on 03/27/2013 9:38:43 AM PDT by Free in Texas (Member of the Bitter Clingers Association.)
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To: NormsRevenge

Ban fat lesbian crossings.


7 posted on 03/27/2013 9:42:51 AM PDT by yobid (Catastrophic failure is the only solution)
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To: NormsRevenge
Toll Bridge Program Manager Tony Anziano said engineers are "pretty confident" the problem with the bolts is not a design issue...

Pretty confident. Those are words I don't want to hear about any building, bridge, or aircraft.

8 posted on 03/27/2013 9:44:47 AM PDT by Flick Lives (We're going to be just like the old Soviet Union, but with free cell phones!)
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To: NormsRevenge

It seems like everything made today is crap and things made a long time ago are light years ahead.


9 posted on 03/27/2013 9:47:24 AM PDT by moviefan8
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To: Free in Texas

I believe Kiewit (used to be Peter Kiewit & Sons) is the builder. They are also the ones making the pontoons for the new Lake Washington floating bridge, which are a mess. Leaking, rebar rusting, rebar mislocated or missing completely, and the state is making excuses for them and wasting our money, not to mention the safety of those who will be driving on this bridge.


10 posted on 03/27/2013 9:47:41 AM PDT by beelzepug (Telling other people they need to die is a good way to get your own lamp blown out.)
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To: yarddog
I do remember he said there are a lot of injuries caused by people replacing the nut which holds lawn mower blades on. He said they sometimes just use mild steel nuts or bolts or whatever they are.

That information alone made FR worth reading today.

11 posted on 03/27/2013 9:50:57 AM PDT by Gamecock ( If we distort the gospel, that distortion will influence and affect everything else that we believe)
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To: NormsRevenge
According to the article, some of the bolts were damaged when they became loose.

Sounds like a possible engineering problem and the amount of torque used when installing the bolts.

The S.A.E. has ratings on bolts, and it seems the engineering for the bridge should have allowed for worst case conditions -- not best case conditions.

In the 1970's, I worked for a computer company (Microdata) that built a computer based on best case conditions for circuits. It did not account for slow parts.

Of course, semiconductor devices were just started to be used for memories as well as other devices.

The original 1K MOS memories were terrible devices that came out of Silicon Valley then...

12 posted on 03/27/2013 9:54:15 AM PDT by topher (Traditional values -- especially family values -- which have been proven over time.)
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To: Free in Texas
Why can't they do their QC and test the parts before installation. Disclaimer- I am no engineer.

You *never* buy 200+ 18' bolts without specifying their performance. Each bolt probably costs more than $10K, so it's a multi-million contract.

Here is the machine that you use for testing metals for strength. This is just a well instrumented hydraulic press, backward. Samples of special shape are made, and then the machine pulls on them, accurately recording the tension and the deformation. This gives you the stress–strain curve. Eventually the sample breaks.

Even if the company that made bolts doesn't have such a machine, it would be sheer insanity to buy a hundred tons of steel without sending a sample to an independent lab for these tests. You would want a chemical and a crystallographic analysis in addition to that. This is what the engineers did after the bolts failed; that's why they are telling us that the steel was wrong (not the right type, or the right type made incorrectly.)

Now the manufacturer of those bolts is going to lose their shirt on this deal. I'm sure their profit margin is not fat enough to cover redoing all bolts and still staying in black.

13 posted on 03/27/2013 9:55:37 AM PDT by Greysard
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To: Flick Lives

“I’m pretty sure this gun isn’t loaded.”

“I think your parachute is packed right.”

“I’m pretty sure I got all the sponges out of your body cavity.”

“Almost positive there’s enough cash to cover the check.”

Where have all the adults gone? Is there really a Galt’s Gulch?

That I didn’t get an invite means I better step up my own game.


14 posted on 03/27/2013 10:00:03 AM PDT by RinaseaofDs
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To: topher

They came loose because they were elongating beyond elastic limits or even breaking under tension.


15 posted on 03/27/2013 10:00:12 AM PDT by SWAMPSNIPER (The Second Amendment, a Matter of Fact, Not a Matter of Opinion)
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To: Greysard

Defective parts or defective design? More stress on the bolts than the engineer predicted?


16 posted on 03/27/2013 10:00:36 AM PDT by DManA
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To: NormsRevenge
Further down in the article, this bridge has been plagued by a number of problems.

Apparently, they had concrete deck sections MADE IN CHINA that has caused quite a bit of trouble in the 10 year history of this bridge.

Cheap things from China is also a serious problem in this bridge: concrete sections fabricated in China caused considerable delay in the 10 year history of attempting to get the bridge built.

In fact, according to the article, it sounds like trying to save money having the concrete deck sections MADE IN CHINA has probably cost more money in the long run than doing it right in the United States.

17 posted on 03/27/2013 10:00:57 AM PDT by topher (Traditional values -- especially family values -- which have been proven over time.)
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To: SWAMPSNIPER
Would that be because of defective material (hydrogen in the steel) or poor engineering (underestimating the stress)?

This is not even the stress of an earthquake causing these problems, and as someone mentioned, the bridge is supposed to withstand an 8.5 magnitude quake...

18 posted on 03/27/2013 10:03:11 AM PDT by topher (Traditional values -- especially family values -- which have been proven over time.)
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To: topher

>> Sounds like a possible engineering problem and the amount of torque used when installing the bolts.

Or unexpected forces on the assembly.

How does one accurately torque an 18’ bolt?


19 posted on 03/27/2013 10:04:09 AM PDT by Gene Eric (The Palin Doctrine.)
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To: Free in Texas

He is right in a sense- you build and you test.

Usually you end up confirming your design is OK, but occasionally you find an issue like this.

That is why you test.


20 posted on 03/27/2013 10:05:18 AM PDT by Mr. K (There are lies, damned lies, statistics, and democrat talking points.)
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To: Free in Texas
See Reply #13.

This poster claims it is sheer insanity to spend millions of dollars on bolts and not QC them.

21 posted on 03/27/2013 10:06:29 AM PDT by topher (Traditional values -- especially family values -- which have been proven over time.)
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To: NormsRevenge

Bolts made in China?


22 posted on 03/27/2013 10:11:01 AM PDT by tflabo (Truth or Tyranny)
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To: SWAMPSNIPER
They came loose because they were elongating beyond elastic limits or even breaking under tension.

Or thermal expansion. The longer a bolt is, the more it grows and shrinks in response to heating and cooling, and these were 17'.

23 posted on 03/27/2013 10:20:00 AM PDT by tacticalogic ("Oh, bother!" said Pooh, as he chambered his last round.)
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To: NormsRevenge
Unlike the Chinese-built deck sections, the bolts - some as long 17 as feet - were produced in the United States.

Sounds like in the former Soviet Union....

The nail factory made their quotas every year....

increasing the size of the nails....(big ones are easier to make)

Ended up with a huge pile of 50cm long nails that nobody brought.

24 posted on 03/27/2013 10:23:45 AM PDT by spokeshave (The only people better off today than 4 years ago are the Prisoners at Guantanamo.)
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To: topher
Hydrogen embrittlment usually comes from plating chrome or anti corrosion layers such as zinc or cadmium.

It is standard to bake the bolts at about 600f after plating to remove the hydrogen

May have been hard if they did not have a 18 foot long oven

25 posted on 03/27/2013 10:26:55 AM PDT by rdcbn
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To: DManA
Defective parts or defective design?

Can be both. However design of bolt- or rivet-connected bridge spans is a very well known process. Bridges of this type were built for more than a hundred years, entirely without computers; all you need is printed tables. Steel made in China, on the other hand, with no quality control and no incoming inspection, is a very likely culprit. An engineer doesn't claim that "the steel has too much hydrogen" until he has the lab test results in hand.

A comment above mentions that some bolts were loose. If the holes are too large this can result in uneven loading of bolts - and then indeed some will be sheared off, and then the rest follows. If the bolts are not tight then they will experience axial stress instead of shear stress, and the thread will be torn off. It's all very obvious when you look at the bolt, and the guys who are investigating are usually experienced troubleshooters.

26 posted on 03/27/2013 10:38:56 AM PDT by Greysard
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To: NormsRevenge
Caltrans insists the new span is safe...

I still distantly miss the beaches once in a great, great while.

27 posted on 03/27/2013 10:43:11 AM PDT by Standing Wolf
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To: NormsRevenge

About seven years ago, the oil field went through a period of buying Chinese drill pipe. Failure after failure after failure.


28 posted on 03/27/2013 10:44:46 AM PDT by razorback-bert (I'm in shape. Round is a shape isn't it?)
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To: yarddog

ASTM specs.


29 posted on 03/27/2013 10:47:09 AM PDT by Cobra64 (Common sense isn't common anymore.)
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To: rdcbn

Not that hard to contract out. Friend of mine works in a place with an industrial oven several hundred feet long.


30 posted on 03/27/2013 10:49:26 AM PDT by Hillarys Gate Cult (Liberals make unrealistic demands on reality and reality doesn't oblige them.)
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To: topher

When you torque a bolt, even the toughest alloy, it stretches almost like a rubber band. It has to hold that state of tension without elongating beyond a certain point and loosening, or breaking, and it must hold this property over time. Design involves choosing the proper material for the expected load but sometimes the best calculations fail in practice.


31 posted on 03/27/2013 10:58:41 AM PDT by SWAMPSNIPER (The Second Amendment, a Matter of Fact, Not a Matter of Opinion)
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To: NormsRevenge
♫ Look for the Union Label ♫
32 posted on 03/27/2013 11:02:52 AM PDT by BobL (Look up "CSCOPE" if you want to see something really scary)
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To: NormsRevenge

The problem in California is not the bolts, it’s the nuts.


33 posted on 03/27/2013 11:05:31 AM PDT by reg45 (Barack 0bama: Implementing class warfare by having no class.)
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To: SWAMPSNIPER
Then the design must allow for some of the bolts to fail and the rest to be able to handle the load.

Considering what happened with the Nimitz Freeway pancaking during an earthquake, going above-and-beyond should be done in a place like San Francisco.

The reference to the pancaking of the Freeway was that the freeway had two layers. The earthquake caused the top layer to come down on the bottom layer. Some folks were crushed in their cars as a result, as I recall.

34 posted on 03/27/2013 11:09:14 AM PDT by topher (Traditional values -- especially family values -- which have been proven over time.)
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To: topher

They will all fail, given time. You can extend the time but it will affect other considerations, appearance, cost, etc.


35 posted on 03/27/2013 11:20:55 AM PDT by SWAMPSNIPER (The Second Amendment, a Matter of Fact, Not a Matter of Opinion)
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To: Greysard

You could, and should, do a simple nondestructive hardness test on the material being used to make the bolts before the bolts are made and before any other test are done.

You could do a hardness test on enough material to make 288+ bolts in about 2 days max.

That would tell you if the material is up to specs before wasting any more time or money on it.

Too soft or too hard chunk it.

No point in spending any more time or money making a bolt when it’s going to be junk anyway.


36 posted on 03/27/2013 11:21:39 AM PDT by IMR 4350
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To: NormsRevenge

You have to understand that this is a Cal Trans project, and Cal Trans is one of the most incompetent organizations within the State of California.

Several years ago in Orange County on a major freeway interchange where Cal Trans was in charge of constructing freeway “flyover” ramps, they discovered at a very late stage that the pre-stressed concrete was below acceptable quality. Initially they thought that the entire set of flyover ramps would have to be torn down. They finally found a way to “rework” them but it took nearly two years to do so.

In the case of this bridge, there was no excuse for both the general contractor and Cal Trans to have strength tests run on those bolts as well as all major steel components. But what the hay, this is California, and that just about says it all these days.


37 posted on 03/27/2013 11:22:46 AM PDT by CdMGuy
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To: razorback-bert

In the 70’s and 80’s it was American steel that was junk.

In one job alone I rejected over 1 million feet of 2 3/8” tubing.


38 posted on 03/27/2013 11:34:33 AM PDT by IMR 4350
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To: RinaseaofDs

When I’m “pretty sure”, and I often am, I check.


39 posted on 03/27/2013 11:41:43 AM PDT by Flash Bazbeaux
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To: topher
This is not even the stress of an earthquake causing these problems, and as someone mentioned, the bridge is supposed to withstand an 8.5 magnitude quake...

The GG Bridge was built in the early 1930's. In the 1980's, for the 50th year celebration, they allowed a mass of people to walk the bridge, completely filling it with people (jammed together weighing much more than any load of vehicular traffic). The bridge flattened out from it's arch but everything held together, and engineers were able to relax from their fear of a collapse (politicians wanted the people walk). That's 1930's U.S. steel! Nowadays, replacement steel pieces regularly break on the Oakland side of the Bay Bridge, some having damaged cars. Part of the reason for the new section.

40 posted on 03/27/2013 11:49:27 AM PDT by roadcat
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To: yarddog

I was in that business for about a decade. Structural grade bolts are subject to stringent requirements. In fact about 20 years ago cheap Chinese counterfeit bolts were the cause of a collapse in a shopping mall in St Louis IIRC.

Selling counterfeit or mismarked fasteners is now a Federal crime.


41 posted on 03/27/2013 12:23:23 PM PDT by Lurker (Violence is rarely the answer. But when it is it is the only answer.)
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To: Greysard

Thank you most kindly for your informative response.


42 posted on 03/27/2013 12:49:57 PM PDT by Free in Texas (Member of the Bitter Clingers Association.)
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To: moviefan8
It seems like everything made today is crap and things made a long time ago are light years ahead.

You must be a youngster.

All I remember is 12,000 mile spark plugs, 20,000 mile brakes, and 20,000 mile tires.

A 100,000 mile car was a real outlier. Now that's the average car on the road.

43 posted on 03/27/2013 12:53:44 PM PDT by nascarnation (Baraq's economic policy: trickle up poverty)
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To: Greysard

I am an electroplater and metal finishing engineer.

I do not know of any plater in the USA with a 17’ oven. If the bolts are 147KSI in tensile or harder than RC32, they should have been baked for at least 4 hours before plating and a number of hours after plating. The post-plating bake is determined by hardness or tensile. I would have adjusted the bake for the thickness of the part since you have to bake the hydrogen out of the center.

The plater could have sent the parts out to a heat treater with a larger oven, but this has to be done quickly after plating before the hydrogen in the part has a chance to embrittle/damage the steel.

It is possible that the steel could have been embrittled by hydrogen before the parts got to the plater. Certain cutting oils can release hydrogen or it could have been pickled/de-scaled using acid which introduces hydrogen. However, the most common source of hydrogen is corrosion. Letting the raw stock rust is dangerous. After the hydrogen has done its embrittlement dirty work, the stock is ruined. You cannot fix it short of resmelting, reforging, re-heat treating, etc.

I have seen a lot of poor quality steel come through, some of it from U.S. mills, most from China.

As for testing, NASA and the military contractors have to do it, so why not the bridge builders?

This entire incident shows the need to have quality inspectors at every supplier down the line when you are dealing with life-critical parts.

When we built the Space Shuttles, we sent inspectors to the MINES to see where the ore came from and to take samples for the lab.


44 posted on 03/27/2013 2:31:47 PM PDT by darth
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To: NormsRevenge

Let me see here...

“At least 30...”

of

“all 288 of the bolts on the new bridge”

Comes to somewhat over 10%, doesn’t it?

So...

“Caltrans insists the new span is safe...”

Suuuuure it is....


45 posted on 03/28/2013 4:44:19 AM PDT by Peet (Notice: Due to the high price of ammo, there will be NO warning shots.)
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To: NormsRevenge

Seismic designs today are premised upon strength in ductility. Brittle failures were common in the Northridge quake, which changed many structural codes and design philosophies.


46 posted on 03/28/2013 4:47:29 AM PDT by Cvengr (Adversity in life and death is inevitable. Thru faith in Christ, stress is optional.)
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To: Gene Eric

It might be something more fundamental like Min Gauge length or the distance the strain must be transmitted to the bolt for it to behave as a connector.


47 posted on 03/28/2013 4:54:35 AM PDT by Cvengr (Adversity in life and death is inevitable. Thru faith in Christ, stress is optional.)
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To: NormsRevenge

I wonder if the American factory hired illegal workers.

In any event, between these bolts and the Chinese-made parts, when the Big One hits, this sucker’s going into the water.


48 posted on 03/31/2013 2:10:35 PM PDT by Tolerance Sucks Rocks (Drag Me From Hell!)
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To: NormsRevenge

Better engineering and quality assurance management would have avoided this.

Good to catch it now, however.

The bolt weren’t specified well enough, in terms of strengths and/or tests were not made prior to installing said deficient parts.

Somewhere in the bureaucracy perhaps too much diversity trumped engineering & construction practices we used to handle fine.

Maybe the bolts came from a government ordered procurement from a minority owned supplier.


49 posted on 03/31/2013 2:19:25 PM PDT by truth_seeker
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