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from the but-lets-talk-about-their-aquaducts dept.
A long section of the towering Ponte Morandi Bridge completely collapsed in Genoa, Italy, on Tuesday, sending cars and trucks on the A10 highway crashing down below. Dozens of people died in the bridge failure, officials say.
As news emerged from the chaotic scene, the death toll fluctuated several times Tuesday. Prime Minister Giuseppe Conte said there were 22 dead, according to public broadcaster Rai News. But Italy's ANSA news agency has reported at least 37 people died, citing the fire brigade.
Workers have found bodies and vehicles in the massive amount of wreckage left by the collapse — and at least 11 people have been pulled from the rubble alive, Italian media report.
[...] The disaster struck shortly before noon, when one of the bridge's central pillars collapsed during a violent rainstorm. A witness told ANSA that lightning had struck the bridge before the collapse.
[...] The bridge was built in the late 1960s, at a length of more than 3,600 feet. It had recently been the subject of renovation and repair efforts. Italian roadway company Autostrade says the most recent work included consolidating the viaduct's base — a project that included installing a bridge crane.
Besides the obvious news value of this event, I'd be curious of any civil engineers or structural engineers could comment on the engineering behind such things. What causes these types of crumblings to happen, and exactly how reliable is infrastructure around the world?
(Score: 2) by isj on Thursday August 16 2018, @03:11PM (7 children)
Partially informative: https://www.gocomics.com/calvinandhobbes/1986/11/26 [gocomics.com]
Not entirely untrue - there is destructive testing done on many things: utility poles, cars, masts, ...
I recall an episode in BBC Open University at night about masts for electricity cables. It was long and dry and sleep-inducing, but interesting anyway. The civil engineer explained some of the calculations and which factors to include, a clip was shown of the destructive test (pulling the mast sideways), and the engineer explaining that the mast was actualyly2% stronger than anticipated probably because the steel was of slighter higher quality than expected.
I haven't heard about destructive testing of full bridges. Maybe because they are expensive, or maybe because they are mostly unique?
(Score: 2) by RS3 on Thursday August 16 2018, @04:37PM
Um, I'm trying to think of how you would / could do destructive testing on something as big as a bridge. I guess you could just load it up with boulders, then start adding them until it fails, but wow what an expensive test and mess.
You can test small pieces and calculate the additive loads and stresses in the bigger structure.
USA PBS TV science show Nova did a fascinating (to me) series called "Building Big". They chronicled the construction of many building around the world, including London's Leadenhall Building's https://en.wikipedia.org/wiki/122_Leadenhall_Street [wikipedia.org]. I forget which building, but in one of the episodes I remember them testing concrete batches before okaying the next batch's installation.
(Score: 2) by bob_super on Thursday August 16 2018, @06:32PM (2 children)
> I haven't heard about destructive testing of full bridges. Maybe because they are expensive, or maybe because they are mostly unique?
Maybe it's because structural engineers learn math ?
(Score: 2) by isj on Thursday August 16 2018, @07:22PM (1 child)
Engineers do learn math but they also have the good sense to perform empirical tests
(Score: 2) by bob_super on Thursday August 16 2018, @07:47PM
These days you get the computer to calculate the sway and tell you your margin.
Then, at the end of construction, you drive a whole bunch of trucks onto your bridge and measure the flexing against the math.
Nobody does destructive testing on full-scale expensive multi-year (and usually late) projects. Material science has made a lot of progress, and mechanical engineers and architects don't need to trigger a 7.0 quake to verify their margins.
(Score: 2) by fraxinus-tree on Thursday August 16 2018, @08:14PM (2 children)
A reasonable destructive test of a bridge is not only expensive. It is also way beyond current technology. The bridges do fail in many ways - including quakes, minor landslides, winds, ice buildup, material degradation, or a combination thereof. Bearing a static load is something pretty well known in a civil engineering and not usually at fault. And we clearly are not in a position to create a 100km/h wind for the whole bridge.
(Score: 2) by realDonaldTrump on Thursday August 16 2018, @10:44PM (1 child)
There's something called the Wind Tunnel. Which our airplane companies use -- Lockheed, Boeing, Northrop Grumman. So their airplanes will be PERFECTO. And they make a VERY SMALL airplane that fits in the Wind Tunnel. But possibly they can't make a bridge that small!!!
(Score: 2) by Gaaark on Thursday August 16 2018, @11:02PM
If you stick your hand out the window while driving you have, in effect, a wind tunnel. But I hear you have small hands.
:(
--- Please remind me if I haven't been civil to you: I'm channeling MDC. ---Gaaark 2.0 ---