Ok engineers, tear this cheesy video apart!

[Amanita]

http://www.youtube.com/watch?v=hwnKy1mOnM4

Ok, here's something I found on Youtube. It's a clip from a tv movie called 10.5, about all these huge earthquakes.
Here we see Golden Gate Bridge meeting with a rather messy demise, among other things.
Now what's wrong with this picture?

I can name a couple of things- first of all, why would the deck be sagging before the cables even begin to fail?

Second, when the towers fall, wouldn't they fall the other way?

And third- the water in the Golden Gate strait is nowhere near deep enough to swallow up those towers going in headfirst like that, even at its deepest point.
At the tower bases, the water is much shallower. I've got a blueprint page illustrating this last part.

How many more things can you guys find wrong here?

[Kelvin]

Wow - I love that seismo-meter -- how it just cranks out the Richter scale value like a big ol' tachomter. I'm surprised they didn't have a big red line marker on it as well...

The failure mechanism is perhaps a bit unrealistic. As you know the deck & cable system are relatively flexible. So to see the failure initiate as a result of local buckling in the deck and/or overstress in a hanger is pretty dubious. They show a portion of the deck gradually yielding and failing - indicative of a sustained loading pushing a localised group of members into a plastic failure (this is not unrealistic for a stiff system under sustained loading). The reality of a highly flexible system is that overall the deformations can be large - but numerous pieces combing to produce the total deformation, none of which are specifically overloaded.

Look at the machinations that Tacoma Narrows endured in it's superstructure prior to collapsing. Tacoma & Golden Gate were designed using the same prevailing philosophies of the day, only at Tacoma they were pushing the envelope a little more...

So the deck, hangers, and main cables would hold but probably be whipping around like crazy. Cars would be flying all over the place ...

In a seismic event (as compared to Tacoma's wind induced deformations), the towers would bear the brunt of the moving mass (inertia). The towers are more rigid and would be forced into yanking back and forth repeatedly during the event. In the video, they show the tower breaking off, but a more likely result is that it would simply "hinge" as it enters plastic deformation range at which point the deck system would collapse and/or tear apart - depending on which way the towers deform. As the deck does rip away, the mass-induced loading reduces on the towers leaving them highly deformed but otherwise standing through the remainder of the event.

Whether the deck actually submerges or not after it rips away might depend on how deep the water actually is and secondary hydrological effects. There could be the possibility of mini-tsunamis forming in the bay as fault line (under the bay) creates the world's largest wave pool...

[Ilex]

Here's another one:

http://www.youtube.com/watch?v=xpAf8...eature=related

[scalziand]

*If* the towers of the Golden Gate bridge were to fall over, the whole towers from the caissons up would collapse, not merely the portion above the road deck. Also, the entire length of deck between the anchorages would collapse, not just the main span. Happy?

[Tom In Chicago]

Originally Posted by Ilex

Here's another one:

http://www.youtube.com/watch?v=xpAf8...eature=related

I don't get it. . . what's causing the water temperature to rise and why is the water in Lake Mead to rise so quickly. . . the casino scene is just too rediculous to even talk about. . . why would they still have power and why would stuff be falling off the walls, but nothing else moving. . . silly!

. . .

[ChicagoChicago]

Originally Posted by Tom In Chicago

I don't get it. . . what's causing the water temperature to rise and why is the water in Lake Mead to rise so quickly. . . the casino scene is just too rediculous to even talk about. . . why would they still have power and why would stuff be falling off the walls, but nothing else moving. . . silly!

. . .

My guess is lava flowing into the lakebed of Lake Mead. I would have put a bullet to my head if I watched that show when it came on NBC. Just stupid.

[Alex Mackinnon]

I love how fast the dam breaks. The water pressure on that top bit would be miniscule. Why on earth would it crack? Concrete dams can overflow basically with no consequence, and the thermal mass of the lake and dam are huge.

[JordanL]

Originally Posted by Alex Mackinnon

I love how fast the dam breaks. The water pressure on that top bit would be miniscule. Why on earth would it crack? Concrete dams can overflow basically with no consequence, and the thermal mass of the lake and dam are huge.

I can't even fathom the amount of energy it would take to raise the temperature of the entire Lake Meade to 125 degrees in less than a minute...

[JohnMarko]

God, it's so dumb my brain hurts.

First, the overflow spillways would take the water way before anything could reach the top of the dam.

Second, the dam is basically built like one of the Egyptian pyramids - the top is a "knife edge" and the base is almost a 45 degree angle under the lake - the mountains surrounding the dam would likely fail before the damn dam does.

And I love it when they just have to get CLOSER - BELOW the dam - and the lady on the phone has to TELL THEM to get out of there, and they can't figure it out themselves.

But its a TV movie for chrissakes - and it's actually not bad as far as TV goes - so I guess they couldn't afford the proper consultants. Remember, this would have been groundbreaking just a couple decades ago for the movies.

Never fear tho - there are a lot of Saturdays left to go and plenty of time to fill up - I just want to know what the next monster will be, we've already had snakes, spiders, snow spiders, gargoyles, mummies, squids, sharks, sharksquids, and sharkpersons!