Horatius
NWO Kitty Wrangler
- Joined
- May 9, 2006
- Messages
- 29,691
-
Security incident: ISF was recently accessed by intruders. Please change your password, and change it anywhere else you used it. Read more
Proposed Design for Progressive Collapse Demonstration
- Thread starter Myriad
- Start date
BasqueArch
Graduate Poster
- Joined
- Jan 11, 2009
- Messages
- 1,871
Myriad, I know you mean well but you're not a structural engineer. Your experiment won't convice many people of much.
1) Decide what it is you are trying to prove, e.g. does welding steel produce "iron nanospheres", How much "nanothermite" is required to burn through a 1/4" thick steel column with four sides, etc.
2) Contact a testing laboratory such as PSI (PSIUSA.c*m) that has structural and materials engineers. Tell them what it is you are trying to prove or disprove.
3) THEY will design the test that answers your questions, produce reports and give you a price for each.
4) You will save a ton of time, money, and the results will be meaninful for everyone.
Good luck
____________________________________________________________________________
"Again, there are many ways of going wrong ... but only one way of going right;
so that the one is easy and the other hard — easy to miss the mark and hard to hit it. "
- Aristotle
"`Contrariwise,' continued Tweedledee, `if it was so, it might be;
and if it were so, it would be; but as it isn't, it ain't. That's logic.'
- Alice in Wonderland
1) Decide what it is you are trying to prove, e.g. does welding steel produce "iron nanospheres", How much "nanothermite" is required to burn through a 1/4" thick steel column with four sides, etc.
2) Contact a testing laboratory such as PSI (PSIUSA.c*m) that has structural and materials engineers. Tell them what it is you are trying to prove or disprove.
3) THEY will design the test that answers your questions, produce reports and give you a price for each.
4) You will save a ton of time, money, and the results will be meaninful for everyone.
Good luck
____________________________________________________________________________
"Again, there are many ways of going wrong ... but only one way of going right;
so that the one is easy and the other hard — easy to miss the mark and hard to hit it. "
- Aristotle
"`Contrariwise,' continued Tweedledee, `if it was so, it might be;
and if it were so, it would be; but as it isn't, it ain't. That's logic.'
- Alice in Wonderland
AZCat
Graduate Poster
- Joined
- Feb 6, 2007
- Messages
- 1,672
I'm not particularly knowledgeable about this, but I thought in some cases authorities having jurisdiction (like the State of Arizona) adopt parts of OSHA as law. These might even be amended to be more stringent than the original OSHA regulations, so it might be worth your time to check for yourself or consult with a safety professional (I'd be willing to cover Mr. Skinny's time, as long as he takes Ameros).
Hokulele
Deleterious Slab of Damnation
His experiment is intended to win a $1,000,000 challenge offered by one of the CTists. It doesn't have to prove anything other than that a progressive collapse triggered by an initial drop of part of the structure is possible.
Mr. Skinny
Alien Cryogenic Engineer
- Joined
- Dec 4, 2001
- Messages
- 7,843
Yes, there are always "authorities having jurisdiction". Where I work I have to work with fire dept personnel, industrial hygenists, environmental engineers, you name it...they all have their own "authority" via various regulations.
We use Air Force Occupational Safety & Health Standards which must be at least as strict as OSHA but typically are more strict. Then, they hire people like me to look at the safety of things that may not have a standard written for that thing/situation/test. After researching thngs, I give them my evaluation of the risk.
Oh, and I'll accept Ameros I guess. What's the current exchange rate?
Last edited:
AZCat
Graduate Poster
- Joined
- Feb 6, 2007
- Messages
- 1,672
Yes, there are always "authorities having jurisdiction". Where I work I have to work with fire dept personnel, industrial hygenists, environmental engineers, you name it...they all have their own "authority" via various regulations.
We use Air Force Occupational Safety & Health Standards which must be at least as strict as OSHA but typically are more strict. Then, they hire people like me to look at the safety of things that may not have a standard written for that thing/situation/test. After researching thngs, I give them my evaluation of the risk.
Oh, and I'll accept Ameros I guess. What's the current exchange rate?
Exchange rate is simple: however many Ameros I have equals on dollah.
To Myriad, I don't know whether to be impressed or concerned that you spent that much time just to expose Heiwa's incompetence, particularly since he does that for free on his own...
... however, good writeup.
In the off-chance that it somehow becomes a real test, probably in a greatly reduced form after the non-existent prize fails to materialize, I'd be honored to present it along the lines of my Hardfire Modeling Challenge, or contribute technically.
... however, good writeup.
In the off-chance that it somehow becomes a real test, probably in a greatly reduced form after the non-existent prize fails to materialize, I'd be honored to present it along the lines of my Hardfire Modeling Challenge, or contribute technically.
BasqueArch
Graduate Poster
- Joined
- Jan 11, 2009
- Messages
- 1,871
Hoku, you're right I kind of glazed over some of the essay. Speaking of glazed, Myriad left out the line item for the donuts and coffee.
The test project should still be designed by an engineer AND you need the approval signature of Heiwa that he agrees to the test model and results. I guarantee that Heiwa will find some weeeesel objection as to why the test did not meet his standards if he doesn't agree beforehand.
______________________________________
"Again, there are many ways of going wrong ... but only one way of going right;
so that the one is easy and the other hard — easy to miss the mark and hard to hit it. "
- Aristotle
"`Contrariwise,' continued Tweedledee, `if it was so, it might be;
and if it were so, it would be; but as it isn't, it ain't. That's logic.'
- Alice in Wonderland
Hokulele
Deleterious Slab of Damnation
I am sure the GC will catch that with a change order.
Sure, there are still a multitude of details that need to be ironed out, but I am impressed with what Myriad has put into it so far, and it can be used as a great demonstration of how to respond to a challenge.
Interesting contraption!
One horizontal element (a tray) - upper part C - shall one-way crush down 9 other trays connected to columns that in turn are connected some way, so that they also will break sequentially - the latter assembly is part A.
Well, as part Co does not have any columns suggest an improvement.
Part C to consist of two trays connected to columns as in part A. In order for part A to be 10 times part C, part C to consist of 20 trays.
So we have a tower of 22 trays (you can keep total height same as before).
Before drop C on A test, the model shall pass the lateral test, i.e. a force is applied sideways on C and the structure will deflect accordingly without falling apart.
Then the columns between part C and A to be cut, so that part C (two trays + columns) can be dropped on part A.
Suggest the cuts are at different angles and heights!
Part A top will thus consist of a tray with column stubs extending above the tray and part C will consist of a bottom tray with column stubs extending below the tray.
Thus, at impact interface area C/A the structures are equal.
Now drop C on A.
The drop should be so that column stubs contact column stubs and as the stubs are angled, parts C and A will be given a little sideways motion - a tilt. This will then enable the column stubs to contact the top A tray and the bottom C tray, when C displaces further downwards.
Thus the part A columns will contact the part C bottom tray from below, etc.
Note that part C bottom tray will not contact part A top tray at contact. It is the part C column stubs that contact part A top tray.
And then you'll see what happens! No one-way crush down will take place.
Now I'm off on vaccation (or work).
One horizontal element (a tray) - upper part C - shall one-way crush down 9 other trays connected to columns that in turn are connected some way, so that they also will break sequentially - the latter assembly is part A.
Well, as part Co does not have any columns suggest an improvement.
Part C to consist of two trays connected to columns as in part A. In order for part A to be 10 times part C, part C to consist of 20 trays.
So we have a tower of 22 trays (you can keep total height same as before).
Before drop C on A test, the model shall pass the lateral test, i.e. a force is applied sideways on C and the structure will deflect accordingly without falling apart.
Then the columns between part C and A to be cut, so that part C (two trays + columns) can be dropped on part A.
Suggest the cuts are at different angles and heights!
Part A top will thus consist of a tray with column stubs extending above the tray and part C will consist of a bottom tray with column stubs extending below the tray.
Thus, at impact interface area C/A the structures are equal.
Now drop C on A.
The drop should be so that column stubs contact column stubs and as the stubs are angled, parts C and A will be given a little sideways motion - a tilt. This will then enable the column stubs to contact the top A tray and the bottom C tray, when C displaces further downwards.
Thus the part A columns will contact the part C bottom tray from below, etc.
Note that part C bottom tray will not contact part A top tray at contact. It is the part C column stubs that contact part A top tray.
And then you'll see what happens! No one-way crush down will take place.
Now I'm off on vaccation (or work).
Last edited:
Dave Rogers
Bandaged ice that stampedes inexpensively through
I see he's already trying to prepare the ground for that by specifying some further conditions that weren't in the original challenge. Myriad, I would suggest that a further stated condition should be that an independent adjudicator be selected, by agreement between you and Mr. Bjorkman, who shall rule in the event of a dispute on the question of whether the stated conditions of the challenge have been met. I would also suggest some binding agreement in writing between you, enforcible in law, that you will both abide by the decision of the adjudicator. Simply reducing the question to one of incontravertible fact is not sufficient in this case, as Mr. Bjorkman clearly considers no fact to be incontravertible.
Dave
Hokulele
Deleterious Slab of Damnation
In keeping with the construction theme, add in a financial penalty for each change to the original challenge terms.
That is essentially correct.
Please be clear. Is this request for an "improvement" a suggestion based on your own personal preferences for what you'd like to see, or is it a requirement for winning your million dollar challenge?
It's your million dollars and of course you can impose any requirements you like. However, I will point out that no such requirement, that part A (or for that matter any part of the model structure) include columns and multiple floors, is stated in the terms listed in your Heiwa Challenge thread. Nor is any requirement stated that the crush-down must be one-way.
Similarly, the so-called Bjorkman Axiom states:
(Emphasis added.)
There is no mention that this axiom applies only if part A (or indeed any part of the structure) includes columns. In fact quite the contrary. The bolded portion emphasizes that it applies to all structures however constructed, and the first sentence is specifically inclusive of isotropic structures. So, neither multiple floors in part C nor one-way crush-down is required to disprove, by counterexample, the stated claim.
I'll also point out that you yourself have offered models, in support of your claims, that do not include columns at all.
I've explained the importance of scale in progressive collapse. You've just provided a good example of that importance.
Let's suppose I keep the height and overall construction methods the same but double the number trays.
If I kept the overall mass the same, each tray would be about half as heavy. The total gpe of the structure would remain approximately the same. The average load on each connector would remain approximately the same. But the number of connectors that must break for the structure to collapse would have doubled. That's a big change to the energy budget in the collapse dynamics.
If I doubled the number of trays while keeping the trays the same as in the original design, then the gpe would also be doubled, but the energy to break the connectors would be quadrupled, because there be twice as many connectors, and each one of them on average would have to be twice as strong as before to support the structure with the same safety margin. That's also a big change to the energy budget in the collapse dynamics.
If the World Trade Center were the same height but had had 650 floors (about 20" clearance between floors, just as you're suggesting for my demonstration), it might very well not have collapsed on 9/11. But it also wouldn't have been very useful.
So, unless you can state a reason why you think the number of floors should be doubled, or you're modifying your "axiom" or adding new previously-unstated conditions to your challenges, I will choose not to follow that suggestion.
However, if you think it's important, I will modify the design so that 1 tray is dropped on 10 trays instead of 1 onto 9. I've been interpreting the wording of your axiom and challenges as referring to 1/10th of the whole crushing the other 9/10ths of the whole. Perhaps because that's what you've said:
If you now insist that it only applies to 1/11th of the whole crushing the other 10/11ths of the whole, then I'll make that change in the design. (I am curious, though, why this distinction would be that important. Are you saying a wtc tower should not have collapsed if the upper block was 1/11th of the whole, but you would expect it to collapse if the upper block was an entire 1/10th of the whole? Does that mean you accept that the "official theory" of progressive collapse accepted by structural engineers is sufficient to explain the collapse of the south tower, and only the north tower collapse is suspicious?)
Please review the parameters for the lateral test that are presented in the abstract, and tell me whether they are acceptable for your challenge. Or better yet, state the allowable range of parameters.
Is there a reason the sideways force should be on C, rather than on the interface between C and A as I've proposed?
What I've proposed is more than a small nudge; it's actually a rather large lateral impact. Perhaps you might be able to guess how I arrived at the values I proposed? (Hint: individually the weight and velocity I proposed have no particular significance. But if you multiply them together and divide them by another meaningful physical quantity...)
A smaller impact would reduce expenses, so please let me know what the acceptable envelope is. You specified a "small" lateral impact which makes it sound like my proposed impact is much larger than is required, especially since my model is considerably slenderer than the wtc towers were.
What is the rationale for this change? The structures are already equal at impact interface in the current design, since there are no columns inside the footprint of any floor. Again, neither your challenge nor your axiom mentions column stubs as a necessary condition for collapse arrest. And again I can point out that you have proposed and discussed several models of your own, all of them conspicuously lacking in column stubs.
As I said, it's your challenge and once you put up the million dollar stake you can specify any conditions you want when it comes to negotiating the formal challenge agreement. You can demand that the floors be coated with marmalade and supported by rubber chickens if that's your thing. However, adding major new conditions such as one-way crushing or angled column stubs as requirements after reviewing the plan wouldn't speak too well for your confidence that the broad claims you've made will stand up to fair testing. (If these are just suggestions, then that's not an issue. Hence, my request that you be clear on the distinction in the future.)
In any case, I should mention that cutting through the columns between C and A prior to the drop is not acceptable for safety reasons, as it would expose the personnel doing the cutting to undue risks to life and limb.
Yeah, that's the general idea.
The above appears to be a prediction of what will happen, when the whole point of the exercise is to observe what actually does happen.
Unless you're saying I must manipulate the drop (e.g. with careful placement of carefully angled column stubs) to make sure that what you predict should happen actually does happen? That would make little sense, since the challenge you've issued is to show otherwise.
Telling the difference is usually pretty easy. (And for the tough cases, the IRS has pretty good methods for figuring out which is work and which is vacation. But since you're not a U.S. citizen, I suppose that valuable service is not available to you.)
Now, here are some specific questions about the proposal that I'd like you to answer:
1. Are the guy ropes as described in the proposed design acceptable? Note that the proposed design, to keep costs reasonable, is considerably slenderer than the actual wtc towers were, so for safety the possibility of topping from near the base must be ruled out. Your rationale for collapse arrest does not involve toppling of part A, radical rotation of part A, or major horizontal displacement of part A, which the guy ropes would prevent from unexpectedly happening. (Part C is not attached to any guy ropes so it is completely free to tilt, rotate, bounce, or whatever the laws of physics determine.)
2. Are the nailed connections acceptable? Technically, nails (and most other construction fasteners other than welds or adhesives) attach things together by friction. Please clearly state whether or not the nailed connections in the proposal are acceptable under term 4 of the original challenge. (Note that in this design the nails are supporting shear loads as is typical of real-world nailed construction, and that nail failure is not expected to contribute to collapse in the design of the demonstration.)
3. How shall we proceed into the negotiation of a formal agreement between us regarding the challenge terms? I've made a reasonable start by describing the proposed demonstration in considerable detail. But it appears that you do have some doubts or objections regarding the details. I think the best way to proceed would be for you to begin a first draft of the contract, using what I've proposed as the guideline, and that as you do so you communicate with me to make clear any specific objections or additional requirements you are adding, so that we can negotiate precise final terms regarding what is and is not permissible in the demonstration.
4. Just to repeat from earlier, please clarify the acceptable parameter envelope for the side impact test, keeping in mind that the stated purpose of that test is to ensure that the structure is honestly self-supporting and that connections are fastened, not to prove that the structure is strong enough for any particular purpose.
I hope you have a pleasant (or profitable) vacation (or job). If continuing this discussion during that period is not practical, then I look forward to completing the necessary preliminary arrangements when you return.
Respectfully,
Myriad
I like the idea, but what if the first change is removing the penalty for changes? Paradox! I don't want the universe to implode.
Respectfully,
Myriad
Hokulele
Deleterious Slab of Damnation
Somewhat random comment:
I linked to gumboot's "Expertise" thread for another post and noticed that there is at least one construction contractor listed. He/she (although I am pretty sure it is a he) may have some helpful comments as to your design, ignoring the likelihood of the challenge acceptance for the time being.
http://www.internationalskeptics.com/forums/showthread.php?postid=2191263#post2191263
I linked to gumboot's "Expertise" thread for another post and noticed that there is at least one construction contractor listed. He/she (although I am pretty sure it is a he) may have some helpful comments as to your design, ignoring the likelihood of the challenge acceptance for the time being.
http://www.internationalskeptics.com/forums/showthread.php?postid=2191263#post2191263
Homeland Insurgency
Banned
- Joined
- Jun 18, 2008
- Messages
- 1,705
I still don't see the need for it to even be that big.
Just show something able to support something else above it just as long as the weight is evenly distributed. The weight being supported doesn't even need to be made of the same material or even the same weight. Make it of whatever you like. Make the top part as heavy as you like and the bottom part as light and flimsy as you wish.
Just show that the bottom part when weight is evenly distributed can support the upper part forever.
But when that upper weight is shifted it completely crushes the bottom part.
Just show something able to support something else above it just as long as the weight is evenly distributed. The weight being supported doesn't even need to be made of the same material or even the same weight. Make it of whatever you like. Make the top part as heavy as you like and the bottom part as light and flimsy as you wish.
Just show that the bottom part when weight is evenly distributed can support the upper part forever.
But when that upper weight is shifted it completely crushes the bottom part.
Newtons Bit
Penultimate Amazing
- Joined
- Apr 12, 2007
- Messages
- 10,049
Unless you're using a quick setting mix, you need to let the concrete cure for 28-days, otherwise it will be grossly under-strength.
(bold added)
The demonstration you describe would indeed be trivially simple. In fact after reading your post I just did one, in less than 5 minutes, using a rolled up piece of aluminum foil as the bottom part, and an apple as the upper weight. The foil tube held the apple just fine when carefully placed, but crushed when I dropped the apple on it from about 4 inches up.
Unfortunately it doesn't meet the terms of Heiwa's challenge. Specific terms disallow the portions of your description that I've boldfaced.
If you wish to sponsor a challenge of your own, with different terms, please feel free to do so. I'm particularly curious about what proof you will require that the lower part will support the upper part forever. (I suggest you take it to its own thread though.)
The need for the structure designed to win Heiwa's challenge to be large is explained in the "Introduction" section of the OP. The paragraphs following the fourth quote in Post 33 might also be illuminating.
If there's any statement in those sections that you disagree with or don't understand, please point it out.
The key point is the larger the structure(1), the larger the ratio of total gravitational potential energy to the strength of the structural elements required to support the structure in stasis with a given safety margin.
Thank you for your interest.
Respectfully,
Myriad
(1) More specifically, the taller the structure -- but Heiwa is demanding a freestanding structure so for it to be tall it must also be larger in its horizontal dimensions as well.
That's why I said "hardened" instead of "cured."
The concrete is dead weight. Any structural strength it adds (such as to brace the tray frames against twisting) is incidental and should not be needed, especially given that the structure must stand when the concrete is first poured. So, it shouldn't matter if it's under-strength.
Unless the under-strength concrete is so soft that it undergoes excessive deformation during the collapse test, absorbing enough kinetic energy to arrest the collapse. That seems unlikely given the way it's contained in the trays, but it's a possibility I should look into further.
Respectfully,
Myriad
