Stunning video of a bridge collapse in Taiwan

Originally published at: https://boingboing.net/2019/10/01/stunning-video-of-a-bridge-col.html

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It was a bridge too far…

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Made in Taiwan

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Glad nobody was killed. Building bridges is tough.

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That’s just insane. Truck passes middle of bridge, a moment later, a whole wide arc of the roadway gives out, all at once. I only see one possible “twanging” cable just to the right of center. The now-curving roadway becomes too short to reach from end to end, and then drops straight down from those points too, taking the flexed and shortened overhead arch with it. I just can’t figure out what caused the road to collapse if only one cable snapped. The roadway didn’t swing or fall toward one side first. It just goes straight down. Perhaps there WAS only one cable for the whole bridge, just running up and down in serpentine fashion, which had snapped in the center and started sliding freely.

Edit: Yeah, I’ve looked at a few other videos now, and while the cables do look like they’re whipping around a bit by the falling roadway, the overall length of the cables seems to be increasing at the same time. I don’t think they could stretch that much, it all supports the impression that it’s a single long serpentine cable which has snapped in the middle and is pulling loose through the loops it threads through.

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When the cable snapped, the load was suddenly transferred to the other cables, which failed under the increased tension. It cascaded.

The shortened bridge deck pulled The arch off the piers, and fell.

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Why were they filming? And why is the video so herky-jerky?

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Actual video of me driving home from dim sum.

I think it’s someone using a phone to record, web cam or security cam footage, from a monitor and they don’t have the most steady hand.

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Yikes. Su-Ao is the most important port in east Taiwan. Hundreds of fishing boats dock there, and it’s also heavily used for freight and military traffic. There’s another road in, but this is going to make a lot of people’s life harder for some time.

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Kudos to the arch, though!

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JFC. This is something I am actually actively scared of when I drive across bridges.

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See, cascade is literally the first thing I looked for. And I don’t clearly see it, actually. I do see clear behaviour which would not be present in a cascade. Which is why I remain mystified.

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But that AINT the Rhine. And (on a serious note) the loss of life was a lot less.

Yeah, it would have to be in shockingly poor repair to all fail simultaneously from a single lost cable like that. Maybe combined with a design with little redundancy to begin with? Looks like the kind of accident that took many people fucking up over several decades to pull off.

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My day is rich in collapsing bridge content.

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Like the Hyatt Regency, but with disrepair instead of, or perhaps in addition to, bad design. Get that much weight moving, momentum overwhelms tensile strength pretty quick.

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The frame rate is not optimal, but I think the center stay failed first, at the bottom end. You can see between seconds 9 and 10 that the cables to the left of center are all releasing starting from the top of the arch to the left. Look at the length of the gaps above the cable ends. The rate of fall in each will be equal, so the largest gap means it let go first.

It cascaded from the center outward.

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Me too. After the Loma Prieta earthquake I became very aware when I was stopped on or under a bridge.

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the florida item has some new information
might be of interest

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