The Heiwa Challenge

[Heiwa]

The correct proportion should then be, 1/8 of the building crushes 1/110, right?

Actually it is only the lowest elements of part C that contacts the top elements of part A. Stronger elements will then crush weaker elements and as part C is smaller (and weaker) than part A, part A crushes part C.

Quite basic actually. Happens at every collision - vertical or horizontal. And that's the reason why you cannot one-way crush down a structure from top to bottom by a little part of itself.

The Heiwa Challenge is to demonstrate the opposite with any real structure.

 

[bill smith]

Sorry, wrong answer. This is the one your guru keeps missing, so you can be excused for demonstrating repeatedly that it is actually possible to know less than he does. We'll start over.

Thirteen floors fall on top of ONE floor, not ninety-seven.


The thirteen original collapsing floors crushed ONE floor and either did or did not ADD ITS MASS TO THE TOTAL COLLAPSING MASS.

Do your best to concentrate and try again.

One of the problems with your view is that the upper block is always seen as a 'block' while the lower 90% of the building is seen as a collection of individual stacked floors.

Of course the truth is that they are either both blocks (the lower one being 9 times larger than the upper) or they are both collections of floors ( the upper collection being about 10% the size of the lower)

If they are both collections of floors then for each destroyed lower floor there will be one destroyed upper floor (equal and opposite reaction). Obviously as the upper collection diminishes collapse arrest wil soon ensue.

If they are both blocks then the most likely scenarios are that the upper block either will bounce or it will crunch into the lower block with the energy being taken away by the local damages both blocks will equally receive. Again there will be collapse arrest.

Nowhere here is there a mechanism for removing or significantly weakening the massive support structure of the lower part. In addition Bazant only put the distance of fall at something like 20 inches.

 

[GlennB]

One of the problems with your view is that the upper block is always seen as a 'block' while he lower 90% of the building is seen as a collection of individual stacked floors.

Of course the truth is that they are aither both blocks (the lower one being 9 times larger than the upper) or they are both collections of floors ( the upper collection being about 10% the size of the lower)

If they are both collections of floors then for each destroyed lower floor there will be one destroyed upper floor (equal and opposite reaction). Obviously as the upper collection diminishes collapse arrest wil soon ensue.

That was very reasonable, up to the bolded part.

However, there comes a point where the mass of accumulating and accelerating debris alone (not the theoretically intact floors above) is sufficient to destroy the next lower floor being impacted. I would agree that in reality the upper 'collection of floors' would be subjected to massive stresses and collisions that would gradually cause its destruction as it fell. Not least because it was sliding downwards (skewed, chaotically) around still-standing parts of the core.

Bear in mind that Bazant and others were analysing a limiting case - that most favourable to collapse arrest - not proposing an exact collapse mechanism. Yet, in their analysis, the structure still fell. These is no need to fixate on Heiwa's 'falling blocks/pizza boxes/lemons' analogy. It's an essentially useless distraction.

 

[bill smith]

That was very reasonable, up to the bolded part.

However, there comes a point where the mass of accumulating and accelerating debris alone (not the theoretically intact floors above) is sufficient to destroy the next lower floor being impacted. I would agree that in reality the upper 'collection of floors' would be subjected to massive stresses and collisions that would gradually cause its destruction as it fell. Not least because it was sliding downwards (skewed, chaotically) around still-standing parts of the core.

Bear in mind that Bazant and others were analysing a limiting case - that most favourable to collapse arrest - not proposing an exact collapse mechanism. Yet, in their analysis, the structure still fell. These is no need to fixate on Heiwa's 'falling blocks/pizza boxes/lemons' analogy. It's an essentially useless distraction.

As I see it this is the important thing to bear in mind:-

One of the problems with your view is that the upper block is always seen as a 'block' while he lower 90% of the building is seen as a collection of individual stacked floors.

Of course the truth is that they are aither both blocks (the lower one being 9 times larger than the upper) or they are both collections of floors ( the upper collection being about 10% the size of the lower)

It is self evident that we are talking about two collections of floors. The top 10% is far more vulnerable because it is completely disconnected top and bottom while the lower 90% is firmly planted in the ground . One strike of column butt on column butt on one side will put the whole top assembly out of shape and cause it to start disintegrating. A disintegrated 10% will not bring enough coherent forces to bear on the structure below to cause a global collapse of 80-90 thousand tons of structural steel.....and definately not at anything like the speed that it fell at.

 

[GlennB]

The top 10% is far more vulnerable because it is completely disconnected top and bottom while the lower 90% is firmly planted in the ground . One strike of column butt on column butt on one side will put the whole top assembly out of shape and cause it to start disintegrating.

No. That's a daft way to view it.

No matter how sturdy and well planted the lowest columns were, they would not prevent the breakage of their much thinner continuation higher up the building. The bolts and welds up there are not supported by the massive continuation buried in vast foundations 300m away. Each floor simply supports what's above it. The bolts and welds are the weakest link.

And - p.s. - the upper section was not 'disconnected' at the very top at all. The hat truss was a very substantial structure.

 

[CORed]

Maybe in some technical sense, but enforceability matters. Saying you have a contract but it's just not enforceable is like saying you have ice cubes but they're just not frozen.

Among the likely problems with enforceability in this case are: numerous unclear and contradictory terms, jurisdictional issues (Heiwa and I are citizens of different nations), my anonymity on the forum, and the supposed offer passing the "no reasonable person" test (as in, no reasonable person would believe Heiwa was truly offering a million dollars for demonstrating something that every structural engineer in the world already knows).

Respectfully,
Myriad

There is also the "blood out of a turnip" problem. Even if a contract exists, and you manage to get a judgment for a million dollars, it is quite likely that Heiwa does not have a million dollars, or a million dollars in assets, or even potential future earnings of a million dollars.

 

[Heiwa]

Each floor simply supports what's above it. The bolts and welds are the weakest link.

Yes, each floor just supports the furniture, people, &c, what's above it. Just above it.
And there is just ONE weakest link. But a broken bolt or weld will not produce, e.g. global collapse or one-way crush down as required by The Heiwa Challenge.
To assist prospective Challengers; calculate the energy/force to break the weakest link at each stage of destruction and ensure that there is enough energy and, very important, a force to apply on the link.

 

[bill smith]

Yes, each floor just supports the furniture, people, &c, what's above it. Just above it.
And there is just ONE weakest link. But a broken bolt or weld will not produce, e.g. global collapse or one-way crush down as required by The Heiwa Challenge.
To assist prospective Challengers; calculate the energy/force to break the weakest link at each stage of destruction and ensure that there is enough energy and, very important, a force to apply on the link.

Do you mean ONE weakest link in the sense that most likely the connections on only ONE side of each floor will give way leaving the rest of the floor hanging off the other columns ?

PS.Sorry about the corrections

 

[Heiwa]

Do you mean ONE weakest link in the sense that most likely the connections on only ONE side of each floor will give way leaving the rest of the floor hanging off the other columns ?

It all depends on the structure and its elements and how part C contacts part A. If the lowest floor of part C contacts a column of part A, the weakest link is the part C floor element! The part A column, very strong element that carries all structure above, punches a hole in it.
But the part C lowest floor is enormous - 4000 m² - and consists of many sub-elements - trusses, floor pans, &c. The only common property is that they are all very weak; they can just carry what is put on them, e.g. furniture and people.
So how to break the strong elements? The columns! That's the Gretchen question!

 

[Grizzly Bear]

Yes, each floor just supports the furniture, people, &c, what's above it. Just above it.

Horribly worded but about the only thing that is even remotely correct in this entire post. The floors were not structural in the sense that they were not responsible for holding the building up, rather they served as a transfer element to provide the rigidity the structures needed for wind loads and lateral stability. They also carried the live loads inside the buildings.

And there is just ONE weakest link. But a broken bolt or weld will not produce, e.g. global collapse or one-way crush down as required by The Heiwa Challenge.

I hate to be the bearer of bad news but buildings tend to be built with quite afew nuts, bolts, and welds. And all of these work in unison to support whatever loads are applied to them. What do you think happens when the loading capacity for all of them is overwhelmed Heiwa?

To assist prospective Challengers; calculate the energy/force to break the weakest link at each stage of destruction and ensure that there is enough energy and, very important, a force to apply on the link.

Also add the amount of mass falling onto those elements as each successive floor fails. Also take into account how the loads are applied. One of the first things you learn when studying structures in a college level course is that the load capacities change when the application of the load changes or the angle by which the load is applied changes, or the length of unsupported column length. I'm surprised (not rly) you aren't aware of this.

 

[bill smith]

It all depends on the structure and its elements and how part C contacts part A. If the lowest floor of part C contacts a column of part A, the weakest link is the part C floor element! The part A column, very strong element that carries all structure above, punches a hole in it.
But the part C lowest floor is enormous - 4000 m² - and consists of many sub-elements - trusses, floor pans, &c. The only common property is that they are all very weak; they can just carry what is put on them, e.g. furniture and people.
So how to break the strong elements? The columns! That's the Gretchen question!

Thanks. It looks to me as if the contact between he first colliding floors of parts A and C is quite different from subsequent contacts between floors.
The first contact, assuming that the base of C and the top of A were more or less completely flat would mean that the concrete floors would meet at the same time as the core columns in both parts began their work of punching through floors. When those first floors were pulverised and gone the still present core columns would have protruded 12 feet put of the next available floors in both parts. That would mean that the next floors of the top and botttom parts would have each been transfixed. by 47 12-foot long core columns before any concrete-on-concrete contact occurred. In turn that should mean that those concrete floors were pretty well broken up prior to concrete-on-concrete contact . Concrete-on-concrete contact is all that can explain the pulverisation we saw. I can't think of any other way it can possibly be explained in the conventional way.

 

[GlennB]

Yes, each floor just supports the furniture, people, &c, what's above it. Just above it.

If you'll look at the context, I clearly wasn't talking about 'floor' in the sense of an area where one walks around, but floor in the sense of 'storey'. We were discussing the support of the rest of the building above each 'floor' (storey)

 

[FineWine]

One of the problems with your view is that the upper block is always seen as a 'block' while the lower 90% of the building is seen as a collection of individual stacked floors.

Of course the truth is that they are either both blocks (the lower one being 9 times larger than the upper) or they are both collections of floors ( the upper collection being about 10% the size of the lower)

If they are both collections of floors then for each destroyed lower floor there will be one destroyed upper floor (equal and opposite reaction). Obviously as the upper collection diminishes collapse arrest wil soon ensue.

If they are both blocks then the most likely scenarios are that the upper block either will bounce or it will crunch into the lower block with the energy being taken away by the local damages both blocks will equally receive. Again there will be collapse arrest.

Nowhere here is there a mechanism for removing or significantly weakening the massive support structure of the lower part. In addition Bazant only put the distance of fall at something like 20 inches.

You are as clueless as your guru. What sort of madness is this? Twenty or so floor collapse. Of course they suffer extensive damage as they collapse, but their mass doesn't magically disappear. GRAVITY drives them downward. When they hit the next floor in line, their mass is approximately the mass of twenty floors (a bit less as debris has fallen over the side). They do not hit a "block"; they hit the next floor. It is crushed and collapses with the original collapsing mass. Your guru spouts nonsense. You know nothing and you choose to swallow lunatic ravings instead of trying to learn from real engineers.

This is why your crazy movement died. This is why you run from the question about what predictions you people have gotten right.

 

[bill smith]

You are as clueless as your guru. What sort of madness is this? Twenty or so floor collapse. Of course they suffer extensive damage as they collapse, but their mass doesn't magically disappear. GRAVITY drives them downward. When they hit the next floor in line, their mass is approximately the mass of twenty floors (a bit less as debris has fallen over the side). They do not hit a "block"; they hit the next floor. It is crushed and collapses with the original collapsing mass. Your guru spouts nonsense. You know nothing and you choose to swallow lunatic ravings instead of trying to learn from real engineers.

This is why your crazy movement died. This is why you run from the question about what predictions you people have gotten right.

Where do you kep getting 20 floors from ? It was about 13. Not that the difference matters all that much. The initial contact was one floor on one floor- what else ?

Loose gravel and chunks of material (the broken up floors) do not povide the same coherent force that a solid object might. It apples lots and lots of much smaller forces that the upstanding structure can more easily deal with. In fact the gravel would behave more like a liquid, running over and around impediments.

 

[FineWine]

Actually it is only the lowest elements of part C that contacts the top elements of part A. Stronger elements will then crush weaker elements and as part C is smaller (and weaker) than part A, part A crushes part C.

Quite basic actually. Happens at every collision - vertical or horizontal. And that's the reason why you cannot one-way crush down a structure from top to bottom by a little part of itself.

The Heiwa Challenge is to demonstrate the opposite with any real structure.

Stop the madness. The entire collapsing mass falls on the next floor in line.

 

[FineWine]

Where do you kep getting 20 floors from ? It was about 13. Not that the difference matters all that much. The initial contact was one floor on one floor- what else ?

Loose gravel and chunks of material (the broken up floors) do not povide the same coherent force that a solid object might. It apples lots and lots of much smaller forces that the upstanding structure can more easily deal with. In fact the gravel would behave more like a liquid, running over and around impediments.

No, your clueless guru is hopelessly wrong. As I say repeatedly, the entire collapsing mass falls on the next floor. Which weighs more, a ton of solid ice or a ton of ball bearings?

 

[BigAl]

Where do you kep getting 20 floors from ? It was about 13. Not that the difference matters all that much. The initial contact was one floor on one floor- what else ?

Loose gravel and chunks of material (the broken up floors) do not povide the same coherent force that a solid object might. It apples lots and lots of much smaller forces that the upstanding structure can more easily deal with. In fact the gravel would behave more like a liquid, running over and around impediments.

Wrong again. With each floor, the mass increases, the velocity accelerates and the force is the sum of all the material falling down on the next floor.

 

[CORed]

Where do you kep getting 20 floors from ? It was about 13. Not that the difference matters all that much. The initial contact was one floor on one floor- what else ?

Loose gravel and chunks of material (the broken up floors) do not povide the same coherent force that a solid object might. It apples lots and lots of much smaller forces that the upstanding structure can more easily deal with. In fact the gravel would behave more like a liquid, running over and around impediments.

Obviously you've never seen a rockslide (or its afternath). Otherwise, you would never post something this ignorant.

 

[Typicallucas]

Obviously you've never seen a rockslide (or its afternath). Otherwise, you would never post something this ignorant.

Good point.

 

[GeeMack]

One of the problems with your view is that the upper block is always seen as a 'block' while the lower 90% of the building is seen as a collection of individual stacked floors.

Of course the truth is that they are either both blocks (the lower one being 9 times larger than the upper) or they are both collections of floors ( the upper collection being about 10% the size of the lower)

If they are both collections of floors then for each destroyed lower floor there will be one destroyed upper floor (equal and opposite reaction). Obviously as the upper collection diminishes collapse arrest wil soon ensue.

If they are both blocks then the most likely scenarios are that the upper block either will bounce or it will crunch into the lower block with the energy being taken away by the local damages both blocks will equally receive. Again there will be collapse arrest.

Nowhere here is there a mechanism for removing or significantly weakening the massive support structure of the lower part. In addition Bazant only put the distance of fall at something like 20 inches.

Go ask the physics teacher at your high school about this. Come back and let us know what you learn.