What Happened To the Bay Bridge?

farnsworth writes "Tony Alfrey has put together a fascinating page with some history, analysis, and possible explanations for what ultimately went wrong with the recent emergency repair of the San Francisco-Oakland Bay Bridge. The bridge has been closed for days and is not scheduled to open for days to come, hugely inconveniencing more than 250,000 people a day. His analysis touches on possibly poor welding, a possibly flawed temporary fix, and the absence of a long-term fix or adequate follow-up by Caltrans, the agency responsible for the bridge. Slashdot is a great engineering community; what other insights do you have on the bridge situation?"

Comments

Re:still dead!

[Prien715]

Slashdot is a great engineering community

He must be new here;)

Speaking as the owner, I'm furious

[Anonymous Coward]

Four years ago I bought that bridge along with a package of subprime mortgages to highly qualified homeowners.

And where did the retro-fit funds go?

[ttimes]

McSweeny's has a great article on this, broad reaching in its investigation of the many problems at hand. One thing that troubles me: I have seen many times in the California University and Transportation groups, failure to use earthquake retro-fit funds - they simply use them elsewhere. Its only when a problem like this arises that we learn they have not been used.

Re:And where did the retro-fit funds go?

[theshowmecanuck]

I noticed that on the bay bridge dot org web site they had a bunch of high production value movies, animations, etc. presenting the bridge as well as the construction efforts. These aren't cheap to produce. I wonder how much money is wasted making beautiful 'feel good' presentations that could help reduce costs... maybe this is where some of the funds go. I suspect there are a ton of projects that California runs where they have spent several hundred thousand or even millions on 'feel good' movies and web sites. I'm not saying keeping the public informed is not important. But it kind of looks like they think because they have Hollywood they need to make the audiovisual aspect Hollywood grade. Or maybe it is a way to employ all the film school graduates and keep them off the street. It just seemed a tad much to explain that they are building a bridge.

small

[anonieuweling]

The USA is small. Think bigger than just the 250k people. The whole infrastructure in the USA is lagging in maintenance, care, repairs and/or replacements. The USA needs trillions to fix this problem but other shenanigans of course have higher priorities. P

Re:small

[neoform]

The US spends $1.15 trillion a year on 'Defense', only bleeding heart liberals would want to waste any of that money on silly things like infrastructure.

Re:small

[Grishnakh]

It was George Washington that sent U.S. Marines into northern Africa for the first foreign war. Please explain why anything more recent is any different than that action?

I believe that was Thomas Jefferson, not Washington. The Barbary Wars were in the early 1800s, after Washington had already finished his two terms.

However, I'll tell you exactly what's different between these wars.
1) Back then, the Barbary Pirates were attacking American vessels with American crews, and demanding payments. Iraq never attacked America. Yes, Saddam was violating some UN rules and not being terribly cooperative, but that could have been fixed with some cruise missiles and bombs, not an all-out invasion, for much less money and without distracting us from the task in Afghanistan. And Afghanistan never attacked us either, though Al-Qaeda did. That could have been taken care of by attacking Al-Qaeda directly in their caves and training camps, without having to take over the entire country.

2) More importantly, back in the 1800s, when we went to war, we fought to win, and didn't worry about civilian casualties. When America attacked the Barbary Pirates, they attacked them in their port cities like Tripoli, by bombarding the cities. They didn't worry about civilians, because the civilians were guilty of allowing the Pirates to stay there and run the place. In WWII, we also didn't worry much about civilians. We happily dropped tons of bombs on cities and killed civilians by the hundreds of thousands. It was their fault for allowing an evil dictator to take power over them, and we certainly didn't worry about them turning into terrorists later. We crushed them, and they became quite compliant afterwards. Now, we worry far too much about civilian deaths, which just makes it impossible to win a war.

Re:small

[hey!]

Depends on the rate of return you can get on other investments.

True story. I had a guy working for me who applied for a loan on a sailboat. This was a non-profit, so there were a lot of rich kids doing the noblesse oblige thing. Anyhow the bank calls, and afterward the guys says, "they turned me down".

"Why?" I asked.

"They screwed up. They said I didn't qualify because my income was only 40K."

"I don't pay you that much," I said.

"Actually 40K is my bi-weekly income, but I wanted to get a loan because my investments are returning higher than the loan interest rate."

What you want is the net value of the United States to increase as much as possible. You want the debt to go down relative to that figure. No major corporation *ever* tries to pay down all its debt. It would be insane, because they'd be paying opportunity costs. Just like my young friend, they don't worry about just one side of the ledger. They maximize their net worthy subject to whatever limitations liquidity puts on them. Naturally, this is not an option most of us ordinary mortals have.

What you really need to worry about isn't debt alone, but what you are using the liquidity the debt gets you to do. In other words, spending the money wisely. Spending on maintaining critical infrastructure *should* be a no-brainer. You don't say, "we're going to stop painting this very important bridge because we want to reduce our debt." That would be moronic. Likewise, even if you didn't have a nickel of debt, spending money on something that doesn't return anything is just as moronic.

Re:small

[moosesocks]

That's only if you count Alaska, which is disingenuous at best, given that it's huge, and almost completely unoccupied. Continental Europe occupies 3.9 million square miles, while the 48 contiguous US states occupy 2.9 million square miles. However, the population density of Europe is indeed approximately double that of the "lower 48" (181 people/mi^2 in Europe vs. 94.5 people/mi^2 in the US)

If we're only talking about the coastal regions, you'll find that the US East coast is almost continuously urban from Boston all the way down to Richmond. Europe has nothing that can compare to that sort of density.

The west coast is a bit more sparse, although California follows population patterns very similar to what you'd see in a typical European country.

Re:small

[jamstar7]

Attacking Al-Qaeda directly is what we did. Afghanistan did exactly what you referred to in Tripoli. They protected and gave cover to those 'doing evil'.

The situation in Afghanistan in 2001 was similar to the situation in Cambodia in 1970. Inside the capital of (Phnom Penh/Kabul), the (Royal Family/Taliban) ran things. Outside the city limits, the countryside was controlled by (the Khmer Rouge/various 2-bit warlords like the Northern Alliance). (The Royal Family/The Taliban) had effectively zero power and influence outside the capital.

The reason why bin-Laden was so far out in the boonies (couple hundred miles!!) in Afghanistan was, even the Taliban didn't like him. Pre-Soviet Invasion, he was just some radical kid with a big checkbook, nobody really important other than having close family ties with the Saudi royals. Even the mujahadim thought he was a nutball. His real influence? About as far as the distance between his pen and his checkbook. And of course when the US demanded the Taliban immediately turn over bin-Laden, the Taliban, having just enough police to clamp down on Kabul and about as much real military to provide a couple hours' target practice to the Northern Alliance, told the US they just couldn't do that. Not wouldn't, couldn't, as in, having no capability of doing a particular thing, in this case, handing bin Laden over. The US of course instantly informed the entire planet of the 'Afghani government's refusal to hand over bin-Laden. About the only people to really listen were inside the US. Everybody else already knew that 'Afghani government' is one of those contradiction in terms like 'military intelligence' and 'jumbo shrimp'.

Wrong audience

[Noose For A Neck]

Slashdot is a great engineering community; what other insights do you have on the bridge situation?

No, Slashdot is mostly made up of computer janitors; the greatest insight you'll get out of most of the posters here is, "hurrr durr, the bridge must've been running Windoze! LOL!", with maybe a little "omg the twin towers were collapsed by EXPLOSIVES!!!!"-style conspiracy theory and "THE GOVERNMENT IS BAD!!!" braindead libertarianism thrown in for color.

Re:Wrong audience

[demonlapin]

They did withstand airplane impact. What they did not withstand was hours of several-thousand-degree fire.

Re:Wrong audience

[Waffle Iron]

In interviews I've seen, the architects stated that the assumption was that any collision would involve a plane (specifically a 707) lost in the fog, flying slowly and trying to land. Such planes would not be fully loaded with fuel since they would be at the end of their trip, and they wouldn't be piloted by terrorists pegging the throttles at top speed.

The scenario envisioned was more like what happened to the bomber that hit Empire State building in 1945. It wasn't that big of a deal.

Re:Wrong audience

[moosesocks]

During a botched takeoff, the first thing a pilot does is to begin dumping fuel as fast as he safely can. Jet fuel is similar to kerosene, which evaporates quickly in the atmosphere, usually before hitting the ground.

Most aircraft cannot survive a landing with fully-loaded fuel tanks (unless the plane itself is carrying an unusually light passenger/cargo load).

Also, the flight patterns around Newark, JFK, Teterboro, and LaGuardia would all avoid lower manhattan, even in the event of a severe failure or navigational obstacle. Odds are, they'd end up in the meadowlands, the hudson river, or a residential area. Briefly browsing takeoff-related aviation accidents around NYC seems to confirm this.

The odds of a fully-laden jumbo jet hitting a building in lower Manhattan by accident are close to nil.

Caltrans Says

[tlord]

The engineering authority in charge of the bridge and repairs already gave their answer to this on the morning news (yesterday, I think):

They found the crack. They designed the "band-aid": the saddle, T-bar, rods, etc. They had it fabricated and installed.

In subsequent days, they went back up to look at how it was doing. They found that it was vibrating more than they thought it should: it wasn't as rigid as it was designed to be. They recognized that this would lead to fatigue and failure.

They began designing the improved "band-aid" and planned to install it sometime in coming weeks.

To their surprise, *perhaps* related to unusually high winds, the system failed sooner than they thought it could.

The completed their improved design and are now installing it. (And they are counting their blessings that nobody was killed: they got lucky, that way.)

-t

Closing the bridge makes it 100% safe

[Anonymous Coward]

If their goal was to improve the safety of the bridge, then they totally succeeded.

Re:Lack of redundancy

[ucblockhead]

Actually, they are currently building another bridge right next to it. These fixes are all to a structure that they hope to retire in a few years.

Re:still dead!

[tsm_sf]

He must be old here.

Re:My insight

[ucblockhead]

The Oakland Bay Bridge isn't much of a landmark, really. In any case, it is *extremely* important to note that the western span of the Bay Bridge, which is a suspension bridge, is perfectly sound, as is the landmark (but less used) Golden Gate Bridge. All of these problems are with the eastern span, which is a cantilever bridge.

Welders are a scapegoat

[SethJohnson]

As a hobbyist welder, and someone who has worked with welders in an industrial setting, I strongly doubt that the welding is the culprit. "Faulty welding" doesn't happen on something of the scale of a bridge. If it's one welder working, maybe. But this bridge repair would have had dozens of welders working. No one person's welding could have broken a bridge. Sure, they were under a time crunch, but that doesn't result in shoddy welds. It means more welders are put on task. Those guys are trained and certified and their work is defined by specs that they follow and then is inspected by city or state engineers. If the welding is the problem, it means the original spec was faulty.

Seth

Re:Welders are a scapegoat

[Snowblindeye]

I strongly doubt that the welding is the culprit. "Faulty welding" doesn't happen on something of the scale of a bridge.

You're right on. If the author of the article would have watched any of the Caltrans news conferences, they would have answered some of his theories.

The weld that he claims failed was clearly described as only being tacked, not structurally welded. That weld wasn't supposed to hold the structure together, the tie rods were, which failed. One of the improvements they are making now is to replace the tacking with a structural weld, so that even if something broke, these pieces won't come apart. The other improvements center around reducing vibration, especially in the tie rods

Who wrote that article anyway? Some guy on the internet who looks at some pictures of the repair and thinks he knows what a bunch of engineers working on the problem didn't know?

What happened indeed

[hardihoot]

Perhaps if the state of California hadn't diverted transportation funds and had actually used the money to maintain its infrastructure (similar to New Orleans not using its allocated money to maintain the levee system) this probably would not have happened.

Raids of Public Transportation Funds

Ruling on a case started in 2007 by the California Transit Association, the California Appeals Court found that the gimmicks used to reroute public transit funding to other programs were not consistent with voters' intent for the funds to be spent on public transportation

nearly $2.5 billion was diverted away from transportation programs

Re:Lack of redundancy

[Graymalkin]

The Bay Bridge is not the only way from Oakland to San Francisco, there's the Richmond-San Rafael bridge to the North and San Mateo bridge to the south. There's also BART and various ferries and worst case scenario a trip through the South Bay and then up the peninsula. There's lots of ways into the city even if one of the bridges is out of service for some reason. The past two labor day weekends the Bay Bridge was shut down for repairs (the latest of which apparently caused the current problems).

The positioning of the Bay Bridge is limited by the layout of both San Francisco and Oakland. The Bay Bridge already spans one of the narrowest points between the cities and is bisected by Yerba Buena Island to reduce the effective length of the individual spans. There's nowhere else to really put another bridge in the area. There's no other spots with convenient freeway locations on both sides of the bay which would require whole new sections of freeways be build which means buying out a whole bunch of land that people already live on and a host of other problems. This construction would be in addition to building a whole new bridge.

Re:Lets see here...

[glsunder]

"In 2003, Californians sent $50 billion more to Washington in federal taxes than the state received in federal expenditures. Representing a slight increase from levels that have held steady for three preceding years, the Golden State’s imbalance set a new record for any state, surpassing the previous mark (set also by California, in 2000 and 2001) of $48 billion."

http://www.calinst.org/pubs/balance2003.htm

Maybe if that weren't the case, California wouldn't be so broke right now.

Closed for DAYS? Lucky California.

[sajuuk]

Consider yourself lucky Californians. Us dwellers of Northern New York have a much bigger problem than you have if we want to get to Vermont. The NY DoT let the Crown Point Bridge, one of only two bridges across Lake Champlain fall into utter disrepair and it is now closed indefinitely. The shortest 'detour' to go across the lake and into Vermont adds around 100 miles to the trip, just to get to the crossing.

Re:still dead!

[JWSmythe]

    Aw, everyone knows Slashdot is full of experts. Even if we don't know what we're talking about, we'll still pretend to be experts. Well, until a real expert speaks up and makes us look stupid. :)

What engineering is really about.

[Animats]

No, Slashdot is mostly made up of computer janitors.

I do get that feeling now and then.

Many years ago, I went to a serious engineering school. There, the final exam in a course in structural engineering was this:

At the final exam, each student had to design a link to attach two pins some distance apart. There were obstacles between the pins and the link had to go around then. The design was to be for a specified grade of aluminum and had to support a specified load. Students knew in advance what the exam would be, except for where the obstacles would be. For the exam, you sat at a drafting table, and turned in a drawing.

The link you designed was then machined out of aluminum by a machinist. It was put in a testing machine and placed under the specified load. If the link broke, you failed the course.

If the link didn't break, it was weighed. Lower weights yielded higher grades for the course.

This is how good structural engineers are trained. (I'm not one. I was in EE/CS, and we had a different make-or-break exam.)

Re:Meanwhile, in Segovia....

[QuoteMstr]

You have no clue what you're taking about. Roman legionaries (who were paid) and paid laborers were used to build Roman infrastructure.

Re:still dead!

[CharlyFoxtrot]

    Aw, everyone knows Slashdot is full of experts. Even if we don't know what we're talking about, we'll still pretend to be experts. Well, until a real expert speaks up and makes us look stupid. :)

Pshuh, I don't need an expert to make ME look stupid !

Re:Don't blame the three caltrans employees

[TubeSteak]

Instead, they dump cones everywhere, dig holes everywhere, then quickly move on to the next site. Sure, you'll never actually see a CALTRANS guy working but it sure as hell looks like they must have a lot of people doing the work if they can dig up that much crap and have roadworks every couple of hundred yards.

Most highway work gets done at night. Late at night.
If you can figure it out, I have no doubt CA's dot.ca.gov website will show you where and when they're actively doing construction.

I drive around during the day and see cones.
I drive around at night and I see construction crews.

Re:Meanwhile, in Segovia....

[photonic]

Note that there is a large selection bias in the example you cite. The Romans were great engineers, but I am pretty sure they also built a lot of shitty bridges and aqueducts. It is a sort of natural selection, the ones that are still standing today happen to be the good ones.