Split from: First Impressions are everything...

[William Rea]

I am disappointed - you are either an engineer who should know better muddying the waters for those who do not have any engineering experience, or you are not a very competent engineer. I recall the muddying of the jurors minds in the OJ trial, where "reasonable doubt" somehow became "any doubt, regardless of total lack of evidence and no feasible or conceivable explanation" by cynical lawyers who should have known better. This is not a world where "how the towers fell" is simply "a matter of opinion" and NIST is "one opinion" and there is a wide divergence of opinion and debate as to what occurred. NIST may be a "theory" but it is supported by the facts and the analysis of experts and the consent of the engineering community. It may not be "exactly" what happened, but it is easily 95%.

I am disappointed you introduced the OJ trial, politicking.

I am intruiged at your estimation of 95% is that a fact or an opinion?

Referring to Almonds post, he applies 1.6 as a multiple for live loads in structures. By that figure it appears that the designers had 62.5% confidence in the facts of their design. Educated opinion then accounted for 37.5% of the final design decision.

I ask you, structure designers only know 62.5% of the facts, how can you be 95% sure the structural engineers at NIST could know "exactly" what happened.

At which point I quote from NIST NCSTAR1 Disclaimer No. 4...

"NIST takes no position as to whether the design or construction of a WTC building was compliant with any code since, due to the destruction of the WTC buildings, NIST could not verify the actual (or as-built) construction, the properties and condition of the materials used, or changes to the original construction made over the life of the buildings. In addition, NIST could not verify the interpretations of codes used by applicable authorities in determining compliance when implementing building codes. Where an Investigation report states whether a system was designed or installed as required by a code provision, NIST has documentary or anecdotal evidence indicating whether the requirement was met, or NIST has independently conducted tests or analyses indicating whether the requirement was met."

They have enough doubts about the initial boundary conditions to add a disclaimer.

 

[William Rea]

Answer my question first, then I'll answer yours.

DR

That's your prerogative.

 

[William Rea]

Where is that definiton of opinion when you need it?

I can help you there...

Main Entry: opin·ion
Pronunciation: &-'pin-y&n
Function: noun
Etymology: Middle English, from Anglo-French, from Latin opinion-, opinio, from opinari
1 a : a view, judgment, or appraisal formed in the mind about a particular matter b : [SIZE=-1]APPROVAL[/SIZE], [SIZE=-1]ESTEEM[/SIZE]
2 a : belief stronger than impression and less strong than positive knowledge b : a generally held view
3 a : a formal expression of judgment or advice by an expert b : the formal expression (as by a judge, court, or referee) of the legal reasons and principles upon which a legal decision is based

Taken from Merriam-Webster which I am lead to believe is something of an authority on words.

 

[William Rea]

Again, taking the positivist view, you have one of two options. You could accept the NIST view as the most likely one given the evidence, or you could use the evidence against the NIST theory to support an alternative collapse theory. If you refuse the NIST theory, other theories like it (that is, supported by similar amounts of evidence) must also be refused.

I repect your viewpoint because it appears that whilst you are a positivist you are able to accept fallibility and are therefore not an absolutist driven by dogma.

I hope I have not misinterpreted you.

 

[The Almond]

I have a question, if you were designing an office complex, why would you include things like people and fax machines in the safety factor?

Re-reading my post, I think I might not have made it clear. The people and fax machines are included in the design load. For offices, I think it's 150 pounds per square foot. In strength design (now the industry standard), we multiply the live load by 1.6 to get the final design load.

The 1.6 represents the future possibility that the load conditions may change. It is not merely meant to cover up deficiencies in design or errors in calculations. Consider this:
Case 1: August 2006
A 100 square foot space (10 feet by 10 feet) has 100 people in it. If each of them weighs 150 pounds, that would be 150 pounds per square foot. The maximum moment will occur at the center of the room (assuming that it is simply supported around the four corners). The combined load is 15,000 pounds, and the maximum moment is PL/4. That's 15E3 * 10 / 4 = 37.5 kip feet. The stress in a given beam supporting the floor (simplifying this problem to a single beam) is M*S where S is the section modulus. If you pound through the math by assuming that you have a rectangular beam whose moment of inertia is 1/12bh^3 made of A36 structural steel, you get a final thickness of the beam as 0.29 feet or 3.53 inches.

Case 2: January 2007, fatties on parade.
Each office person now weighs 175 pounds after holiday festivities. At 175 psf, the maximum moment is now 17,500 pounds. The maximum moment is now 43.8 kip feet. The beam now must be 3.82 inches thick. Consider, however, that once everyone is in the room, the room fails. Everyone on the top floor crashes into the bottom floor, killing all involved.

A 16% increase in weight produced a nearly 8% increase in the thickness of the beam, and the only thing that happened was that everyone gained weight.

The point is that loads change, and a deviation of 8% is not insignificant when you consider that an under-design will result in the deaths of every person in the room. The truth of the matter is that you cannot account for all of the changes people will make to their spaces, and you cannot account for the combined effects of many small changes.

What multiple factor do you apply to the static load?

There are many factors that you apply to various loads. The design load ends up being the load that causes the most severe reaction on the structure. In masonry design, walls are usually designed for 1.3 times the wind load plus 1.6 times the live load. Most of my reinforced concrete designs involved the summation of 1.2 times the dead (static) load and 1.6 times the live load.

 

[William Rea]

Re-reading my post, I think I might not have made it clear. The people and fax machines are included in the design load. For offices, I think it's 150 pounds per square foot. In strength design (now the industry standard), we multiply the live load by 1.6 to get the final design load....There are many factors that you apply to various loads. The design load ends up being the load that causes the most severe reaction on the structure. In masonry design, walls are usually designed for 1.3 times the wind load plus 1.6 times the live load. Most of my reinforced concrete designs involved the summation of 1.2 times the dead (static) load and 1.6 times the live load.

Thanks for the data.

I'm afraid I am of the generation in the UK that was only exposed to the Metric System in Science and Mathematics education. It's fortunate that the multiples are dimensionless! Pounds and Feet go over my head in Engineering terms.

Ironically I weigh myself in Stones and Pounds and drink Pints of milk and often refer to thousandths of an inch in daily interactions! I think this is the influence of my Imperial fluent mentors in the past. At times I have even mixed Metric and Imperial quoting 30cm +0.010"/-0.005". Madness.

 

[William Rea]

You mean the 300,000 pound plane I use to fly was based on opinions? Best guess opinions. Darn they were good opinions. I am not sure what you do but I sure do not want opinions building my next plane...We could have lost 10 or 20,000 people on 9/11. Some of the lessons we learned in 93 helped save lives. Now using science the new buildings will have features added learned from 9/11 and work of NIST, and real engineers and scientist who study 9/11. WTC7 is rebuilt using lessons learned. Facts, not opinions,

Sorry to break it to you Beachnut but, there aren't as many facts in the world as you might like to think. Being an Engineer I'm sure you've also used phrases like "The most likely outcome will be..." or "On balance our opinion is that the best way forward is...".

NIST NCSTAR1 Page 19...

"What follows is the result of an extensive, state-of-the-art reconstruction of the events that accompanied and followed the aircraft impact. Numerous facts and data were obtained, then combined with validated computer modelling to produce an account that is believed to be close to what actually occurred.
However, the reader should keep in mind that the building and the records kept within it were destroyed, and the remains of the building were disposed of before the congressional action and funding were available for the investigation to begin. As a result there are some facts that cannot be discerned and thus there are uncertanties in this accounting. Nonetheless the National Institute of Standards and Technology (NIST) was able to gather sufficient evidence and documentation to conduct a full investigation upon which to reach firm findings and recommendations. The reconstruction effort, the uncertainties, the assumptions made and the testing of these assumptions are documented in Part II of this report."

 

[The Almond]

Thanks for the data.

I'm afraid I am of the generation in the UK that was only exposed to the Metric System in Science and Mathematics education. It's fortunate that the multiples are dimensionless! Pounds and Feet go over my head in Engineering terms.

Ironically I weigh myself in Stones and Pounds and drink Pints of milk and often refer to thousandths of an inch in daily interactions! I think this is the influence of my Imperial fluent mentors in the past. At times I have even mixed Metric and Imperial quoting 30cm +0.010"/-0.005". Madness.

You know, when I was going through school, I used to fight my professors tooth and nail to use the metric system. I loathed imperial units and the fact that I can't just multiply by 1 x 10^x to convert between square centimeters and square meters. But as soon as I got into industry, my supervisors would accept nothing in metric units. Ug.

One nice thing about imperial units, though, is that when you're tolerencing something, you can double or halve the precision of something more easily.

Now, if you'll excuse me, I have to go take 2 2/3rd gills of nyquill.

 

[Gravy]

They have enough doubts about the initial boundary conditions to add a disclaimer.

It would be foolhardy not to. There were legal issues involving billions of dollars surrounding the collapses of the towers. The NIST report does include an extensive section about the design and construction of the towers, which includes building code issues, construction inspections, annual inspections, and modification reports. The section on passive fire protection includes much evidence of how the protection was actually applied to floor trusses and core columns. So it's not as if they were flying completely in the dark in terms of as-built issues.

The insurers were very interested to know if the towers were faulty in design or construction, or not in compliance with building codes. They commissioned an independent engineering investigation, which concluded that the towers were not defectively designed or constructed. The information gathered in that investigation was shared with NIST.

 

[William Rea]

It would be foolhardy not to. There were legal issues involving billions of dollars surrounding the collapses of the towers. The NIST report does include an extensive section about the design and construction of the towers, which includes building code issues, construction inspections, annual inspections, and modification reports. The section on passive fire protection includes much evidence of how the protection was actually applied to floor trusses and core columns. So it's not as if they were flying completely in the dark in terms of as-built issues.

The insurers were very interested to know if the towers were faulty in design or construction, or not in compliance with building codes. They commissioned an independent engineering investigation, which concluded that the towers were not defectively designed or constructed. The information gathered in that investigation was shared with NIST.

Fair comment.

I didn't really see the point of including all that information in the report and found it incredibly dull to read through. They could have referenced it and put a summary in, maybe their salary was proportional to the height of the report.

 

[Gravy]

Fair comment.

I didn't really see the point of including all that information in the report and found it incredibly dull to read through. They could have referenced it and put a summary in, maybe their salary was proportional to the height of the report.

It does make for a slow start. But as someone who didn't know a lot about the details of how tall buildings are built, I found much of it interesting. I also got a charge out of seeing this complex piece of engineering largely done with pencil and paper. Long? Yes. But I'm not sure what good referencing that material would do, since much of is not easily accessible.

 

[beachnut]

It does make for a slow start. But as someone who didn't know a lot about the details of how tall buildings are built, I found much of it interesting. I also got a charge out of seeing this complex piece of engineering largely done with pencil and paper. Long? Yes. But I'm not sure what good referencing that material would do, since much of is not easily accessible.

Only boring people, find things to be boring (or they are not interested in the subject). I have to assume someone who found it boring did not really read it and has shallow knowledge in all aspects of 9/11. I would suspect one who has not even studied 9/11 or the truth movement to be lacking in the ability to even want to understand NIST, after only a day or a few hours.

Some people, and it seems all of the truthers, are unable to understand the difference between facts, evidence, and opinions. Why do some of the smartest people argue everything is opinion, and leave out facts, data, uncertainties, evidence, documentation, and assumptions; plus all things tied to critical logical thinking backed with extensive knowledge and judgment? I find it offensive for someone who admits they have not studied the truth movement or this sub forum to put liars on an equal level with those who use facts and evidence to debunk 9/11 truthers. The ones who think they are above in intelligence of technicians and lay people are the real dolts who have become over educated intellectual idiots who will argue semantics until they have prove to be the buffoon they are.

Why is that?

 

[William Rea]

Only boring people, find things to be boring (or they are not interested in the subject). I have to assume someone who found it boring did not really read it and has shallow knowledge in all aspects of 9/11. I would suspect one who has not even studied 9/11 or the truth movement to be lacking in the ability to even want to understand NIST, after only a day or a few hours.

Some people, and it seems all of the truthers, are unable to understand the difference between facts, evidence, and opinions. Why do some of the smartest people argue everything is opinion, and leave out facts, data, uncertainties, evidence, documentation, and assumptions; plus all things tied to critical logical thinking backed with extensive knowledge and judgment? I find it offensive for someone who admits they have not studied the truth movement or this sub forum to put liars on an equal level with those who use facts and evidence to debunk 9/11 truthers. The ones who think they are above in intelligence of technicians and lay people are the real dolts who have become over educated intellectual idiots who will argue semantics until they have prove to be the buffoon they are.

Why is that?

I said it was dull, and yes, instead of bulking out the report to make it look authoritative they could have left out the section and simply stated that the building met the current regulations. I agree with Gravy that it was probably only the insurance companies who were interested in this anyway. Can you tell me how not reading this section deprived me of any insight on the failure?

Another strawman, I have never argued that everything is opinion, just that not everything is fact or even fact based.

I have left out uncertainties, assumptions and judgements (opinions by any other name). You're seriously saying this when I have just spent the vast majority of this thread saying these are being ignored by the forum who believe there are only facts?

Inverse snobbery about education is just as bad as snobbery about the lack of it.