Slashdot Mirror
Stupid Engineering Mistakes
lee1 writes "Wired has bestowed on us a list of the ten worst engineering mistakes of all time. We have the St. Francis Dam designed by 'self-taught' engineer William Mulholland, which burst and wiped out several towns near LA; the Kansas City Hyatt walkway collapse; the DC-10, and more, but my favorite is the one I'd never heard of: a giant tank of molasses that ruptured in 1919 and sent 'waves of molasses up to 15 feet high' through Boston, killing 21."
Osaka built the world's first sports stadium with a movable roof, which malfunctioned shortly after inception, and the company that made it went bankrupt. The roof has been stuck for the past 5 years. Incidentally, the stadium was built on rubbery landfill, so whenever audiences jump up and down during rock concerts, it causes earthquakes in the neighborhood. Osaka also built a new airport on an artificial island that is sinking into the sea, so it may become the world's first underwater airport. Seoul has had various engineering disasters also, including a department store that collapsed and killed hundreds of wealthy housewives.
this disaster involved a couple morons on a drilling rig in a lake forgetting to carry the two, hitting a mineshaft, and draining the whole lake and part of the gulf of mexico into the mine, along with several ships, etc etc.
VLC FOR MAC IS DYING! IF YOU DEVELOP, PLEASE SAVE IT!!
I can't quite remember, but I seem to recall that the records are scanty on this point -- it may be that the designers of the ship just didn't have the expertise and understanding of buoyancy of later shipwrights, or it may be that there was some kind of kickbacks or other shenanigans that interfered with the building and compromised the design.
When I say "if you look at the ship," though, I am being literal -- because you can. The really interesting thing about the Vasa is that it sank not far from Stockholm harbor, in waters that had a unique mineral consistency. Unlike other parts of the world, for whatever reason the waters in this area were particularly unfavorable to the shipworm. Normally a wooden ship like the Vasa would be eaten up. The Vasa, however, was merely covered with silt at the bottom of the bay, where it lay for hundreds of years.
Eventually -- and again, memory fails me but I believe it was sometime around the 1970s -- the location of the Vasa was discovered and work began to bring it to the surface. Today the entire ship is on display in a museum in Stockholm. The museum building was actually built up around the ship itself. A lot of repair and preservation work had to be done, including plastination of the wood, but it is mostly intact except for the original painting. You can't go onboard, but you can walk around it and view the hull from all sides. It is literally the closest you'll ever get to a 17th century wood-hull sailing vessel -- about five meters away. They've also built a facsimile of the interior decks that you can walk through -- if walking is the word. (Let's just say they made people smaller in those days.)
The museum has salvaged all kinds of other goodies from the ship as well, from cannon to tools to even the bodies of some of the original sailors, all of which are on display. If you get the chance you should check it out -- if you're at all into things nautical, it's a one-of-a-kind experience.
Breakfast served all day!
"I studied _ART_ in college and I spotted the flaw a mile away."
Yes it shows that you studied art and not engineering. We actually studied this failure in one of my classes. The poorly welded box beams probably contributed to the failure but the much larger flaw was changing the support from one in which the box beams would only be supporting the weight of one floor to one in which they would be supporting the weight of all the floors. As I recall a junior engineer approved the change without consulting with more experienced engineers. The construction crew is not at fault because they built the structure according to approved plans and field changes.
The Tacoma Narrows bridge didn't fail due to resonance.
Read that first line again.
It was not resonance, your first year, second year, calculus, dynamics and control systems books all lied to you. Lied. Not truthful. Not correct.
Read: K. Billah and R. Scanlan, "Resonance, Tacoma Narrows Bridge Failure, and Undergraduate Physics, Textbooks;" American Journal of Physics, 1991.
It was not a time dependant thing, therefore, not resonance. The bridge was shaking NOWHERE near its resonant frequencies. The motion of the bridge actually induced "negative damping" . That would sort of be like pulling your parachute and having it drag you to the ground faster and faster as you gain speed. Sounds weird, but totally true. They show in that paper that the bridge under the wind loading becomes a self excited structure and, at a critical wind speed, the eigenvalues of the bridge stucture change sign, causing the bridge to enter an exponentially increasing vibrational state, eventually breaking the bridge down.
I built a cool model of the Tacoma narrows bridge, with controllable air flow, and reproduced this behavior for a college course in experimental design. It was neat to visually watch eigenvalues change in an experiment.
Oh the physics of pulling wool over eyes is so fun. BTW, that "doubling the loading that any physics student could understand" bit in the other posts. Right. Most physics students can't tell you if the box slips downhill or uphill using a free body diagram. Give me a break.