London Bridge Is Falling Down, Falling Down

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sudsmaster

sudsmaster

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Joined
Dec 23, 2004
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SF Bay Area, California
Well, it's the SF Bay Bridge.

Over the Labor Day weekend, during a major reconstruction job, a crack was found in the older part of the bridge, and emergency repairs delayed the reopening of the bridge. That was supposed to be that.

But this afternoon during rush hour, the huge steel plates used to fix the crack fell off, struck some vehicles. Nobody seriously hurt, but the bridge was completely shut down around 8 pm and will be closed indefinitely until they are sure of the cause and it is fixed.

This is the part of the old-style steel cantilever portion of the bridge, which connects Yerba Buena/Treasure Island with the Oakland side. It is the portion of the bridge that failed in the 1989 World Series or Loma Prieta earthquake. The connection to SF from the island is via a double suspension bridge that is similar in construction to the Golden Gate Bridge and has not had any structural problems.

On my way home from night school around 8:30pm tonight, I noticed that eastbound traffic on the connection to the San Mateo Bridge was heavier than usual. Now I understand why... with the Bay Bridge shut down, traffic on all the other cross-bay bridges, and their approaches, will be a mess. I'm glad I have a 3 mile work commute that is all on city streets.

Oh, and the part of the bridge that has been failing is scheduled to be replaced with a fancy schmancy single tower stayed span. Various bureaucratic and contractor delays have tripled the original cost and delayed completion by about 10 years. It should have been done long ago. Now we have a failing structure - without any quake to blame - and an unholy transit mess on our hands.

SF - The City that knows not how.

http://www.insidebayarea.com/dailyreview/localnews/ci_13654754?source=rss
 
Rich,

They were worried about the Treasure Island stretch way back when I had the happy privilege of living in the Marina in 82-83.

And folks in Chicago actually think they have the market cornered on city hall 'games'. Never seen anything before or since like Bay area politics.
 
I really shouldn't put all the blame on SF for this debacle. Most of the blame for the years of delays falls on the Oakland side, and on Sacramento, for bickering over the replacement bridge design. I meant to use the SF designation to indicate the entire Bay Area. It's a great place to live, but when we make mistakes, they are generally whoppers!
 
The latest explanation is that high winds caused the repair to fail.

Currently the repair braces are being welded directly to the cracked "eyebar", which should hold them in place during wind-induced vibration. Additionally larger tie-rods are being used this time.

The bridge is still shut down, and is expected to remain closed until some time tommorrow.
 
Decisions regarding aesthetics . . .

play a big role around here. Jerry Brown, while mayor of Oakland, lead the fight for something more visually pleasing than side-by-side causeways. So a single tower suspension was designed, the cost went way up, and the schedule fell way behind. That wasn't the only reason for delays, there were for sure plenty of them before anyone knew what the replacement section was going to look like, but the flap over the design and the decision to construct the tower certainly added costs and delays to an already woefully bogged down project. 20 years after Loma Prieta is truly ridiculous. And I'm not so sure the new suspension tower is going to look all that great, but meanwhile we're seeing some engineering marvels happening such as the deck replacement over Labor Day weekend, which had to involve some incredibly complex project management to pull off.

Oh, and seeing CalTrans spokesman Bart Ney's handsome mug on the TV when things are happening with the bridge is something I never get tired of.
 
Here's a conceptual shot of the project.

Add some fins and that's one mother of an agitator.

JeffG++10-29-2009-11-05-37.jpg
 
Yeah, it's kind of plain and modern, in particular the portion closest to Oakland. The "agitator" is so close to Yerba Buena Island that you'd have to squint to see it from Oakland anyway.

Ultimately I guess it will be an improvement over the clunky cantilever section, which looks more like an old railroad bridge--well it did have the old Key System trains going across it at first. And double-decked anything, we have learned, is not a good idea in earthquake country.
 
Chronoillogically speaking...

One of the local newspapers is bound to print a chronology of the whole Bay Bridge construction fiasco, but from memory here are the highlights:

1989: Big quake causes a 40 ft section of the upper roadway of the eastern cantilever span to fail, like a hinge, impinging and breaking through the lower deck. One person, who didn't brake soon enough, died when her car went down the 20 ft or so slope.

Bridge is closed for about 30 days while the decks are repaired and reinforced. The entire cantilever structure is retrofitted with extra fasteners to help prevent a future roadway collapse. But the general engineering consensus is that the bridge still might fail in a major quake closer to home. A debate ensues about the desirability of further retrofitting the old structure or building an entire new eastern span.

It's decided that a new span would be cheaper and more effective (as well as being more aesthetically pleasing). It's estimated it might take about five years to build, and should be done by the end of the millenium.

CalTrans unveils their proposal for the replacement. It's not really a bridge at all, more like a causeway. Looks simply like an elevated freeway, which is what it is. Some people in the East Bay are offended, and their innate sensitivity about playing second banana to SF in many cultural matters is stimulated.

A decision is made to hold a competition for a prettier solution. Several interesting designs are proposed, although a full suspension bridge is ruled out due to the soft support on the eastern approaches to the bridge.

Eventually the single tower self-anchored design that Ralph pictured is decided upon. The general design has been used successfully elsewhere, but never on this scale. A lone dissenter in the engineering community, an civil engineering professor at UC Berkeley, says the proposed design is unsafe. He is ignored.

AFter all the debate the estimated cost has gone up, easily surpassing the cost of retrofitting the old bridge, and well above the cost of CalTrans' plainer solution. But it's the heyday of the dot com boom, money is plentiful, and nobody cares.

Bids are put out, orders are placed. Supports are constructed underwater for the span. About half-way through, somebody blows a whistle and says that the welds were not properly inspected, records falsified, etc. Work screeches to a stop. For a year or two, while welds are cut open and inspected. Eventually it's determined they are OK and were over-designed in the first place.

By now the costs have really skyrocketed. The dot com boom has busted. The governor steps in and declares that the original CalTrans design will be built, not the fancy single tower self-anchored design. An uproar ensues. Somehow money is found (I think bridge tolls on all the Bay Area bridges went up a buck) and eventually the work on the fancy design is resumed. Another year's delay.

A bunch of key steel parts arrive from China. They are found to have defective welds. They have to be re-made. Another year's delay.

Then on Labor Day weekend of this year, the bridge undergoes a scheduled shutdown to shift traffic from the original connection to Yerba Buena Island (the anchor point in the middle of both spans) to a new, temporary connection so that work on the old connection can be made so that it connects properly to the new planned span. While all this goes on as planned, ahead of schedule, a big crack is found in one of the key braces in the middle of the old cantilever span. A mad scramble ensues while the problem is analyzed and a fix designed and put in place. The bridge reopening is delayed a few hours. Everyone pats themselves on the back.

Then, the other day, most of the fix falls apart and slams into the upper deck of the bridge, hitting three cars and slightly injuring one driver. The entire bridge has been shut down since then (except perhaps for traffic to/from Yerba Buena/SF/Treasure Island). Traffic in the Bay Area is thrown into chaos. No estimate yet on when the new repairs will be done and the bridge reopened.

Sorry, I don't have dollar amounts or exact dates, but you get the general idea. What was supposed to take about five years to complete, for the public safety, is still not done after 20 years - and costs are easily many times the original estimate.

Don't get me wrong. I think the new span will look wonderful (much better in person than in the concept photos), and will be safer than the old span. But the see-saw decision making and bureaucratic delays have revealed the flaws in our governance. It makes me wonder if public safety was really the main concern in this whole debacle.

And I also think the original proposal would have been fine. A bit boring, but certainly safe and functional. Oakland and the East Bay (where I live and I love it) has so many other things going for it, like actual sunshine in the summer, we don't need a fancy bridge to prove it. But what's done is done, and when all this is over we can all breathe a big sigh of relief (and hope that the lone dissenting bridge engineer at UC Berkeley is wrong).
 
Great summary Rich. Apparently CalTrans is admitting to not considering normal vibrations of the bridge when they designed the band-aid over Labor Day. Between the metal-to-metal action from vibrations over the last several weeks and the high winds we had on Tuesday, a cable strut snapped.

They are saying the current fix will beef up the original Labor Day one and allow some wiggle room for vibration.

I don't think the original engineers for the bridge back in the 30's could even imagine the amount of traffic it would be carrying each day some 80 years after it was designed. It has truly been overworked and the need for replacement has become obvious to all.

P.S., the conceptual pic was posted by Jeff G.
 
"A bunch of key steel parts arrive from China"

In some ways the most disturbing part of the whole story. We used to be known for our bridge projects; now they're imported from China like everything else.
 
Yeah, and those Chinese parts, if I recall correctly, showed up around the same time as all the lead paint toys and tainted dog food and . . . well, you get the idea. You can also bet the greater viewing public in the Bay Area were all rolling their collective eyes when that story broke.

One thing I will like about the new eastern span, and that is that the views will be relatively obstructed. Especially eastbound, where the view from the lower deck seems almost bunker-like. Getting from SF to YBI won't change and everybody will still be using the lower deck, but once they emerge from the tunnel, the view will be spectacular compared to what eastbound drivers see today.

In the meantime, I feel bad for everyone who has been impacted by this current mess on the busiest route in the Bay Region. Here's hoping things are back to normal in time for Monday's commute.
 
Yeah, traffic is still messed up many miles away from the Bay Bridge interchanges.

I also like the more open side by side design. But I wouldn't count on being able to see as much as one might like. The bridge traffic planners will probably erect relatively high walls on either side of the roadway so that drivers are not distracted by the view. That's what they did with the new "S" curve that temporarily reroutes traffic around the new connector construction at the island.

Still, it would be nice to get a glimpse of the East Bay Hills on the way home from SF. As it stands, the lower deck really limits the view.
 

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