The 9/11 Forum

I've never seen this before. Looks interesting, though I've only glanced at a few pages.

Observations of WTC1 Collapse, The Nist/Bazant Model and 2 Particulate Mass Models


This was mentioned in the following post at 911blogger.com

Physics and Engineering
The corralling of this issue as an "Engineering" problem is used all the time by defenders of the Official lie.

I think it's important to stress that before any Engineering analysis of the demolitions er ... sorry 'collapses' is done, then you have to do the Physics, the Empirical Science comes first.

NIST for example only used 2 data points when they declared that WTC7 fell with a 'constant' velocity, and that a constant velocity was consistent with their modelling. They changed this when it was pointed out to them that any one could measure the actual velocity of the fall, and now they say that free-fall is consistent with their modelling.

Bazant does the same when measuring the Potential Energy for WTC Towers, he takes PE for the intact structure and the PE for the rubble pile after the collapse and concludes that there was more than enough energy to collapse the tower, but this is a "progressive" collapse and so he should have measured the Kinetic and PE throughout the collapse.

I've done this for him here.

http://zkt.blackfish.org.uk/119/Simple_CD_Models_WTC1.pdf

Structural Engineering has its foundation in Newtonian Mechanics, and so it follows that no Engineering study can be made without doing the Physics first.

I've checked the available energy throughout the period of measurement for WTC 1. Always much more than is needed to keep the collapse progressing, the rest being in excess.

could i see a brief refutation of the paper, then? he showed his work, can you?

newton --- A computer program does all the calculations. The detailed drop data is available from OneWhiteEye. I fit that to the best fitting curve according to the B&V crush-down equation to obtain the speed. So knowing the PE and the KE one readily obtains the energy expended in each interval. Some of this is consumed by the action of the resisting force; the remainder is excess. I put this in at one stage to check there was nothing aphysical happening in the computer simulation; the actual numbers are unlikely to convince you, although the excess grows rather impressivly large, helping to explain burning cars and dusts and other stuff shoved out to great distances.

You can do for yourself a simipler version by assuming a resistive force of (1/3)g but otherwise "free fall". What do you get?

did you read the paper? 'cause you're asking me questions that are answered there.
he only does calculations for a 12 floor drop, but they show that using NIST/bazant's own assumptions, a deceleration should be observed, even with 100% mass accretion.

it seems to me you are fitting data to a conclusion, and that conclusion is that the rate of descent can be used to calculate how much energy is available as the accelerating mass accumulates.
but, it is not scientifically honest to assume that only X amount of energy was used to crush and break and accelerate stuff based on the change in rate of the collapse, because if it assisted with thermites or space beams or the foot of god, then that energy sink will magically make the energy demands for crushing seem much less than they were in reality. by assuming that you know how much resistance there was as a factor of acceleration or lack of negative acceleration.
i don't assume that the acceleration shows how much resistance the building was able to muster, and i don't assume that the building had the same resistance all the way down. i would say those are unphysical assumptions,
...especially in light of the fact that the buildings were clearly blown up.

crushing forces don't burn cars, either. there is no mechanism for MELTING cars that weren't even close to the building. i seriously doubt any of the fire up above could have had enough oxygen to make it very far in that collapse, either, with all that drywall and concrete dust acting like a giant fire extinguisher.

The anonymous writer of the paper adopts the Bazant assumption that the upper part is rigid ... and then the paper is virtually worthless.

The upper part, let's call it C, is in fact lighter and weaker (not rigid at all) than the lower part, let's call it A, and in an alleged collision impact C (moving) versus A (static attached to ground) at low velocity say 8 m/s and with a certain energy input (1.2 GJ), you would expect C to be severly damaged, energy of which would arrest C on top of A after less than 1 second.

As no vertical, gravity driven progressive structural collapse by a small , weak top part, C, driving through a bigger bottom, also weak but slightly stronger, part of same structural design, A, had ever taken place before 911, it is interesting to note how subject 'gravity driven progressive structural collapse' has popped up on the Internet as somehting old and established.

Let's face it - no global, progressive collapse of any structure by a small top crushing the big bottom has ever taken place before and after 911.

heiwa, did YOU read the paper? he adopted bazant's assumptions knowing that they were unrealistic, and yet still showed that the real world observation from video does not even slightly resemble the predictions of bazant's model, and we know that if mass shedding and overcoming inertia, communition etc. are added into the formula, that the predicted descent will then be even slower. but still, the basic idea is that using bazant's own model of column buckling fromulas, the descent still DECELERATES, not accelerates. he knows there are hardly any buckled columns, so that model is unrealistic in more ways than one. most importantly, it does not predict curves that match observation of the real event.

even those "verniage" demolitions decelerate as soon as the crush zone hit's the ground. and they are only performed on (brittle) concrete buildings, it seems.

newton wrote:heiwa, did YOU read the paper?

I tried, did, tried. No author! And plenty of rubbish! Simply, no structure with parts C and A behaves as Bazant, L, Greening, Benson in one paper and Seffen in another suggest, i.e. that a small upper part C can crush down big lower part A in a gravity field - progressive structural gravity collapse. It seems some Chinese have also jumped on the progressive structural gravity collapse wagon?
NIST proposes that little C can apply energy on big A in a gravity field that A cannot absorb as strain = global collapse ensues, but in our real world C cannot apply that energy! C destroys itself partly first and that's where the energy goes! In the gravity field.
In conclusion - no structure (elements of any kind connected to each other) can collapse by dropping a little piece of same structure on it.

newton --- Don't want to waste my time reading garbage.

To solve the simplified problem of a resistive force of (1/3)mg, it is convenient to first "nondimensionalize", actually just change to non-SI units so that the descending mass m is 1, the height h is 1 and the force of gravity g = 1. Then due to the change in height by h=1, the available PE is 1, the KE is (4/9), the energy consumed by the resistive force is (3/9), leaving (2/9) to be consumed in other ways, such as setting cars on fire.

I will repeat again. There is nothing in the computer program which makes any assumption about how (or why) the collapse started. It simply fits the crush-down equation to the available data. In doing so it gives highly satisfactory answers for those who are not physics challenged.

Heiwa wrote:

newton wrote:heiwa, did YOU read the paper?

I tried, did, tried. No author! And plenty of rubbish! Simply, no structure with parts C and A behaves as Bazant, L, Greening, Benson in one paper and Seffen in another suggest, i.e. that a small upper part C can crush down big lower part A in a gravity field - progressive structural gravity collapse. It seems some Chinese have also jumped on the progressive structural gravity collapse wagon?
NIST proposes that little C can apply energy on big A in a gravity field that A cannot absorb as strain = global collapse ensues, but in our real world C cannot apply that energy! C destroys itself partly first and that's where the energy goes! In the gravity field.
In conclusion - no structure (elements of any kind connected to each other) can collapse by dropping a little piece of same structure on it.

Heiwa, this paper shows that there was insufficient energy loss in the falling mass to accelerate the masses below to the same velocity it was moving at, while also overcoming structural resistance. It is similar to the Missing Jolt in the regard that it shows there should have been serious decelerations and velocity losses by the falling mass, as it impacted floors below, which are not observed. It thus shows the energy to accelerate stationary masses/floors to the fall velocity and remove structural resistance was not coming from the falling mass.

It is just another way to show that the theories of Bazant and the NIST do not match observation.

The paper does not disparage the notion that 1/10th of a structure cannot destroy 9/10ths of that structure before it has been destroyed and rendered ineffective itself.

I would also like to address the administrator in this post. The author of this article said he tried to become a member of the forum here to defend his paper after it was posted. He said he has experienced problems doing so and isn't sure if it is something he is doing wrong or not. I can send his e-mail address to the administrator if that would help.

thank you, T_Szamboti! finally.

did you find that you had wasted your time reading garbage?

Major_Tom wrote:I suspect a few people have gotten no response. We need to check with Greg.

I PM'd Greg today about this. However, I'm sure he gets emailed the same way on membership requests, so it may be of no use.

newton wrote:did you find that you had wasted your time reading garbage?

I believe the paper has some genuine information to convey that causes serious problems for the NIST/Bazant hypothesis for the collapses of the Twin Towers.

I don't see any details given by any who called it garbage, so their unsupported appraisals could hardly be termed fair.

metamars --- Your link to the paper produces a pdf which requires a password to read. Is this something new? Do you have the password?