Moderated Continuation - Why a one-way Crush down is not possible

Z said:
Smith's Law
''Whatever downwards force the moving body exerts on the stationary body of identical construction fixed in the ground is reciprocated by the stationary body equally and oppositely. After that it depends which body is rendered non-viable by mutual erosion first.''

Smith was apparently a moron. This is by no means what happens.



As I said, Smith apparently was smoking crack.
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Bill made it up. I thought it was a geo-tech (soils) truther from the quote. No one in structural says "erosion" when talking about buildings.
 
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Heiwa said:
Yes! I have seen tons of snow and it doesn't flat the house in the real world.
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http://www.metafilter.com/68285/Hartford-Civic-Center-Collapse
On January 18, 1978, 30 years ago today, the 1400 ton 2 1/2 acre roof of the Hartford Civic Center, covered by a blanket of snow and ice, suddenly and completely collapsed, damaging almost all of the seats underneath. Just four hours earlier there was a basketball game packed with 5000 fans. Had it collapsed then, many, if not most, of the fans and players could have died.

The roof was designed with help from some of the best civil engineering consultants, universities, and professors in the industry and had a special computer analyzed 'space frame' design--meant to equally balance the load so that lighter and cheaper material could be used. (Three days later, the space-frame roof of the Long Island University C.W. Post Dome Auditorium (pdf) collapsed "like a giant cracked eggshell".) Lessons learned.

posted by eye of newt (37 comments total) 5 users marked this as a favorite

Why Buildings Stand Up and Why Buildings Fall Down, both by Mario Salvadori, mention this incident and talk a little about what happened. (Unfortunately, even though I've read both more than once, I forget exactly what he said). Structures: Or Why Things Don't Fall Down by J.E. Gordon also covers this, I believe. All three are easy to read but very informative books on structural engineering/analysis.
posted by DU at 7:57 AM on January 18, 2008 [4 favorites]


SNOW CAN'T BEND STEEL THEY PULLED IT.

Seriously, I love things like this because they illustrate the extent to which engineering is an iterative process, and often requires failure in order to develop.
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Heiwa said:
Yes! I have seen tons of snow and it doesn't flat the house in the real world. Good for skiing though ... in the winter. Only 6 months to go! But you are off topic! A part C of snow will not one way crush down a part A of snow.
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Maybe not in your world, but in the actual real world, buildings can be crushed by snow.

http://query.nytimes.com/mem/archive-free/pdf?_r=1&res=9403EEDF113BE033A25756C2A9649D94629FD7CF

http://wenatcheeworld.com/apps/pbcs.dll/article?AID=/20080208/NEWS04/642000082/0/ADVSEARCH

http://query.nytimes.com/mem/archive-free/pdf?res=9F00E4DE1438E233A25753C2A9659C94639ED7CF

There's three examples of buildings crushed by snow - and two of them were crushed by rather smallish amounts of snow.
Now, want to try again?
 
Heiwa said:
Yes! I have seen tons of snow and it doesn't flat the house in the real world. Good for skiing though ... in the winter. Only 6 months to go! But you are off topic! A part C of snow will not one way crush down a part A of snow.
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Makes me wonder why ASCE7 has an entire chapter devoted to snow loads.
 
Newtons Bit said:
Bill made it up. I thought it was a geo-tech (soils) truther from the quote. No one in structural says "erosion" when talking about buildings.
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But what really counts is whether you are prepared to go out on a limb and say that the proposition is not valid- correct terminology or not ?

Reminder:

Smith's Law
''Whatever downwards force the moving body exerts on the stationary body of identical construction fixed in the ground is reciprocated by the stationary body equally and oppositely. After that it depends which body is rendered non-viable by mutual erosion first.''

PS. What word should I use in place of Erosion' ?
 
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bill smith said:
But what really counts is whether you are prepared to go out on a limb and say that the proposition is not valid- correct terminology or not ?

Reminder:

Smith's Law
''Whatever downwards force the moving body exerts on the stationary body of identical construction fixed in the ground is reciprocated by the stationary body equally and oppositely. After that it depends which body is rendered non-viable by mutual erosion first.''

PS. What word should I use in place of Erosion' ?
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It would never be a correct statement. Even if you got better terminology.
 
snow cant hurt a house LMAO

my ex girlfriend and her friend worked at a waldbaums when they were seniors in HS
one winter with a lot of snow the roof collapsed
my gf didnt get hurt
but her friend got trapped at her register and had to be rescued by the FD
http://www.nytimes.com/1996/01/24/nyregion/weight-of-snow-is-blamed-in-roof-collapse.html
The report, which was made public today by Oyster Bay officials, concluded that the weight of rain and snow created a load between 66 and 73 pounds per square foot, far exceeding the total design load of 53 pounds per square foot required by the state building code.
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heiwa
youre an idiot and have no business debating engineering
that one sentence just proves it beyond any shadow of a doubt (even to laypeople)
i hope whoever you do work for never reads this forum for your professional sake

ETA: waldbaums is a supermarket chain in New York
 
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Z said:
And that is why you fail to understand what happened in the collapse. We're not talking a tiny, light brick dropped on a huge heavy brick. We're talking about a composite glass and steel structure that is composed of 14 levels being dropped on another composite glass and steel structure composed of 97 levels (or 96 or whatever).

Think, Bill! Think! The bottom section wasn't a single, monolithic, 97-story brick. It was another composite structure composed of 97 stacked bricks, essentially. Why can you not grasp the idea that you're talking about falling debris with 14 times the mass of a floor impacting first with one floor, then another, then another? It's not a 10--> 90 impact; it's a 14--> 1 impact, followed by a 15--> 1 impact, followed by a 16--> 1 impact, and so forth until the bottom. Hence, a crush-down. It is inevitable.

Say each level has a mass of 100 units.

Now, each level in turn has to be dealt with as a single level on the bottom, because the bottom is not moving and has no momentum. However, the levels on the top have to be treated as a total mass, as the entire top is falling and, most likely, breaking apart into component pieces.

So the initial impact on the bottom section, which occurs to floor 97, is 1400 units impacting a level which has only about 100 units of mass. 1400 units of glass and steel come plowing into a glass and steel structure of only 100 units - destruction ensues.

Now level 96 receives impact from 1500 units of mass. Then level 95 with 1600 units of mass, and so forth.

Bill, do you see what happens here?

BILL! I'm asking you a question, please respond to this post!!!

OK, simple challenge: Make a domino tower of 97 floors height, with room on each floor for ten LEGO men to stand inside. Then, however many dominoes it takes to make one floor, multiply that by 14. Then measure off a few floors of height, and drop those 14 floors worth of dominoes on the 97 floor structure, and see what happens.

OF course, the mass proportions are way off - another fact you twoofers can never seem to grasp is that all factors don't scale the same way, so this model is actually highly inaccurate. But it might illustrate the fact that if you drop 14 times the mass of a single floor onto a structure composed of floors, you're likely to destroy the entire structure.

Im also imagining what would happen if the 10 inch brick was crushed, broken and disintegrating before it contacted the lower brick.
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Bill gives us every reason to suppose that he just might be the rare human who simply can't grasp what you're saying.

But Heiwa! A school somewhere gave this character a degree in engineering!
 
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Heiwa said:
The 1300 other C units - far away and above from the contact area C/A, where 100 C units during impacts 100 A units are being deformed - do not know about what the 100 C units below are doing. When they do, they will start to break apart as you suggest. They become rubble. And rubble cannot impact/destroy A. Please consider that there are vertical elements between the 1300 units transmitting information what the 100 units are up or down to.
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This is insanity, pure and simple. The top twelve floors do not float in midair as the bottom floor of the collapsing mass hits floor 97. Your mad comment about the "100 C units" disqualifies you from the consideration that would normally be due an engineer. Those top twelve floors "know" what the thiteenth floor is doing BECAUSE THEY ARE ALL DOING IT TOGETHER!
Your inability to understand is staggering.
 
bill smith said:
But what really counts is whether you are prepared to go out on a limb and say that the proposition is not valid- correct terminology or not ?

Reminder:

Smith's Law
''Whatever downwards force the moving body exerts on the stationary body of identical construction fixed in the ground is reciprocated by the stationary body equally and oppositely. After that it depends which body is rendered non-viable by mutual erosion first.''

PS. What word should I use in place of Erosion' ?
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You know nothing. Inventing bogus "laws" based on ignorance does not advance your insane cause.
 
Heiwa said:
See post above about bag D full of 1000 m loose parts versus cube C of 1000 m parts connected together.

Please, don't ask more questions. Concentrate on your paper about a part of rubble elements producing bigger force than a part of same but connected elements.
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The falling floors, as you know, are the BIG PART.

You have been exposed. Please stop lying.
 
Heiwa said:
See post above about bag D full of 1000 m loose parts versus cube C of 1000 m parts connected together.

Please, don't ask more questions. Concentrate on your paper about a part of rubble elements producing bigger force than a part of same but connected elements.
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You didn't understand a word tfk wrote, you ridiculous, pompous, empty-headed fraud.
 
bill smith said:
well it would be nice if you explained where you think it is wrong.
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It would be nice if you would start explaining when people ask you direct questions instead of just dodging.

I'm not going to waste a bunch of time outlining a very simple to understand concept that dozens of people have already done. Read what tfk writes.
 
tfk said:
.
You are joking, aren't you??
.

.
If my purpose had been to have you embarrass yourself by blowing a trivial mechanics question, then I would be ecstatic.

Let's take that 1 piece at a time.

In your first answer, you say:
.

.
Oh really??

A direct, inescapable consequence of this (mistaken) assertion is that "controlled demolitions are impossible". According to you, cutting the supports on the bottom floor of any building is useless. According to you, when the building falls & the bottom floor hits the ground, the whole structure will simply "have its columns deform and then come to rest on the solid surface after a little bounce".

Are you sure you want to back this position??

[Insert 100 videos of controlled demolitions here...]


.
http://www.youtube.com/watch?v=qEbYpts0Onw&NR=1
http://www.youtube.com/watch?v=mknStAMia0Q&NR=1&feature=fvwp

Nah, "rubble" could never do any damage.
___

If you simply answer a couple of questions honestly in my next post, I believe that we can put this whole issue to bed.

With a formal proof.

Tom
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A long time ago, someone exposed Heiwa in exactly this manner. It was pointed out that in Heiwa's universe, demolition companies would have to wire every single floor, as blowing the supports on the lowest floor simply drops everything one floor and--Abracadabra!--a "new equilibrium is reached." Needless to say, Heiwa ran away and returned braying about his nonsensical papers. Bill, of course, agreed with Heiwa, although Heiwa wasn't saying anything substantial, relevant, or sane.

You will never get straightforward, coherent responses from this fraud.
 
Newtons Bit said:
It would be nice if you would start explaining when people ask you direct questions instead of just dodging.

I'm not going to waste a bunch of time outlining a very simple to understand concept that dozens of people have already done. Read what tfk writes.
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I've been reading it for a few years now. I like his writing but I am unmoved by most of his arguments. I regret that you will not tell me exactly what is wrong with ''Smith's Law'. Science should be free flowing like the columns in Part C.
 
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