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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?"
For several work mornings the headline on "the new" CNN.com has been "Bay Bridge still closed."
In my head I hear it in the voice of Chevy Chase.
"General Francisco Franco is still dead!"
Four years ago I bought that bridge along with a package of subprime mortgages to highly qualified homeowners.
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.
They should have used duct-tape!
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
I knew people had been talking about the state falling apart due to budget problems, but i didnt think they meant it literally
Good people go to bed earlier.
Lets see, when you have a pretty much bankrupt state (California), a bridge that is too necessary to fully replace without inconveniencing many people, the fact that it isn't exactly in a stable environment, with wind, rain and corrosion everywhere is it any surprise that a bridge that has been up for over 70 years needs some emergency repairs?
Taxation is legalized theft, no more, no less.
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.
Software piracy is victimless theft.
There are four bridges running east/west over the bay, it just happens that there is only one in this particular (useful) location. Also, given that the Bay Bridge has to connect to Yerba Buena island, there's not really a lot of room for another one right next to it. So there is redundancy, but you have to deal with the physical realities of the area.
People use other bridges and the bart.
To say there isn't redundancy, is simply silly.
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
If their goal was to improve the safety of the bridge, then they totally succeeded.
As far as I'm concerned, if a piece of a bridge that has active traffic on it falls off, putting people on the bridge in danger, something went wrong SOMEWHERE.
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.
The cake is a pie
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.
The cake is a pie
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
$5 / month hosted VPS on linux = awesome!
Raids of Public Transportation Funds
nearly $2.5 billion was diverted away from transportation programs
A word fitly spoken is like apples of gold in pictures of silver --Proverbs 25:11
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.
I'm a loner Dottie, a Rebel.
It took me a while to figure out but then I realized: CALTRANS only actually employes three guys.
Driving the 15 in San Diego, I wondered why there were all these construction sites with absolutely no one working. Eventually I pieced it together... CALTRANS only employs three guys and one of those has to hold the sign.
Sure, they could just do one tiny little roadwork at a time. But that'd completely give away the hundreds of millions CALTRANS budget is being spent on three construction workers with the rest going to hookers and blow. 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.
So, when judging the bridge collapse, try not to blame the three overworked guys. They're doing the best they can. Their job was to put up some cones, slap on some duct tape in the two minutes they had assigned, then get on to making somewhere else look busy. If you want to blame someone, figure out who spends the other 99.9% on those hookers and that blow. Imagine how much could be achieved if his habit went to pay for actual workers instead.
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.
Not to take anything away from the impressive feat of engineering that the Roman aqueducts are but there is a big difference between carrying water and carrying 250,000 vehicles ranging between 1 and 50+ tons. Also, the Romans didn't really have to worry about costs seeing as the aqueducts were more than likely built by slave labor.
"Educate the mind but never at the expense of the soul."~Blessed Basil Moreau
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.)
You have no clue what you're taking about. Roman legionaries (who were paid) and paid laborers were used to build Roman infrastructure.
Things like this can't be rushed, plain and simple. Carefully executed planning is what's needed to take on these types of projects.
What XPeter said.
On the gripping hand, they should see if there's anything left of the civil engineering group from the old Hydro-Electric Commission in Tasmania. The collapse of the bridge over the Derwent River when the ore ship Lake Illawara collided with it was repaired by them when the department of roads weren't up to the task. The old Hydro took their sweet time to fix it, but fix it they did and it's better than new (ship-repelling caissons were added). The size and type of that bridge and the treachery of the waters within which they worked make them similar cases.
Do not mock my vision of impractical footwear
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.
karma police: arrest this man, he talks in maths; he buzzes like a fridge, he's like a detuned radio. [radiohead]
Bridges aren't that expensive, it's the assembly and installation that kills you.
Not that this wasn't entirely predictable.