Sunday, February 9, 2014

The New $6.4 Billion Span of San Francisco's Bay Bridge Leaks

File under: Government efficiency.

The San Francisco Chronicle reports:
The just-opened eastern span of the Bay Bridge, already beset by questions about flawed welds and cracked steel rods, has a new problem: It leaks.

Rainwater is dripping into the steel structure beneath the road deck on the suspension stretch of the span, which is supposed to be watertight, Caltrans said. Outside experts say that could pose a risk of corrosion on a bridge that cost $6.4 billion and is supposed to last well into the 22nd century.

"That's a problem, a big problem," said Lisa Thomas, a metallurgical engineer who studies material failure at a laboratory in Berkeley and analyzed bridge rods that snapped last year. "They want it to last 150 years, but with water coming in, something is going to corrode until it's too thin and weak."[...]
Thomas[...] said the waterlogged bike path deck panels and leaks in the steel deck superstructure show that the bridge builders didn't do enough to safeguard the span.

"Letting water get into those compartments is a huge blunder," she said. "Continual water intrusion means continual corrosion.

12 comments:

  1. All that government and they can't manage to build a properly functioning bridge. Utterly laughable and sad at the same time. Here in Palm Beach County our government geniuses let a contractor build a faulty bridge with expansion joints that were so wide you could see through them. Some how they missed it during all the inspections they supposedly did. I always laugh when I hear a left winger assert we need government to build roads. The government sucks at building roads and is even worse at maintaining them even after collecting taxes to do so. But you'll never convince these mindless drones otherwise.

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  2. Even the state is not what it used to be! At least the ancient Romans would build bridges that have lasted till today and do not leak.

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  3. No profit and loss. No accountability. A sure-fire recipe for an epic failure.

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    1. Add to the recipe a contracting process which ensures only cronies can bid, then from amongst that pool choose the ones that are most successful at cutting corners on each of the packages (i.e., lowest "responsible" bidders).

      Then when work gets underway, implement a change order process which guarantees all the low bidders more than make up for what they initially shaved off and no one is held accountable (aside from the governmental entities nominally responsible for oversight)--unless of course there is massive failure or public outcry, in which case the least connected, most expendable crony will be offered up as sacrifice, along perhaps with one or more mid-level government managers.

      And though it's been said many times before, it bears repeating: the solution is NOT to make government work more like a business--this is utterly futile and cannot be done.

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    2. So if only cronies could but how did we end up building it with Chinese steel?

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    3. Both Caltrans and the low bidder, the American Bridge-Fluor joint venture, claimed that China (and Japan) was chosen for some parts because the capacity did not exist in the United States. They said no American fabricator could be found that could build those specific parts at any price.

      Which may or may not have been true but it's their story and they've stuck with it all these years.

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  4. Foolish design. Trying to make a section water tight like that only means making something that will collect water (it gets in but can't get out), rust out (the water wants to get out and it will make its own holes if it needs to) and fail. Caulk type seals fail. Even if done correctly with the sealant between the steel pieces rust near the seal would have created leak paths. Done with the seal like caulk on the outside means failure sooner rather than later.

    Fundamentally the design intent is flawed. One can try and prevent the water from getting in, but it has to get out if it does get in. Use good quality coatings on the steel and make flow paths out of the bridge. Maintain them so they do not become clogged. It doesn't snow there so they don't have to worry about ice build up blocking the path or road salt. If the water can get out quickly it won't cause the coatings to fail and the steel won't rust.

    The way to achieve a water tight structure would have been to use some sort of gasket and then have a bolt arrangement to get even compression. How long it lasts is determined by the specific design. Do something precision like a head gasket on an engine and it might last a very very long time. make a bead of caulk and hope for best... not going to last long at all.

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  5. The fact that they were contemplating naming the bridge after Willie Brown created massive negative karma. That bridge is doomed in the next big earthquake.

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  6. Be like water and you will not be stopped.

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  7. Good enough for government work.

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  8. "This will be building a monument to stupidity"

    Tung-Yen Lin
    Founder: T.Y. Lin International
    The San Francisco architectural firm that designed the new Willy Brown Bay Bridge

    http://m.sfgate.com/bayarea/article/Bay-Bridge-troubles-began-with-design-4616774.php

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    1. Now, now, there were two Mayor Browns on opposite sides of the Bay when this fiasco was first hatched. It's only fair that Jerry get some well-deserved credit.

      Though I have to say, my preference is that it be named for his Imperial Majesty Norton I, Emperor of the United States and Protector of Mexico.

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