So why did you post an equation for the force of the five beams pushing on the girder's studs? Then why did you say it was for the studs in one beam? You posted it when I asked if I could have a copy of the spreadsheet shown in the second video, so I assumed you though it was relevant to the girder not being pushed far enough.
Yeah it is, but I think we need to distinguish where we are talking about reality, and where we are talking about NISTs FEA model. NIST says that their model was heated to 600 excluding concrete and floorpans. Their new push distance requires a temp greater than that, so how can their model be accurate. They said that beyond 600 that the beams would sag, not push.The burden of proof is on NIST and anyone who believes their story, and that should be backed up with something surely?
Is that really what happens in a fire-filled confined room which has been burning for hours?
How was the expansion not constrained when attachment to the rest of the structure has been mentioned, (if not thoroughly covered)? Wasn't it attached?
Why do you avoid mentioning the effects of fire? Of differential expansion in a structure due to fire migration?
Why do you make no mention of creep?
Isn't 600 deg C hot enough for civil steel to creep when carrying a load?
Why do you believe that your story is NIST's "story"?
Your count of unanswered questions is at 37. Abuse doesn't count as an answer.
Final temp = 1110F
Ambient temp = 70F
Delta T = 1040F (change in temp)
Coefficient = 0.00000802
Ambient Coefficient = 0.000006
Average Coefficient = 0.00000701
K3004 Beam = 640.69 inches
Expansion = 4.67 inches
Very interested to see what result you get. For NISTs story to make sense you are looking for a minimum of 6.25 inches.
Thanks for taking the time and interest in this. It is a topic that 'debunkers' have avoided like the plague. I am thinking that you are probably about to find out why.
Is that really what happens in a fire-filled confined room which has been burning for hours?
How was the expansion not constrained when attachment to the rest of the structure has been mentioned, (if not thoroughly covered)? Wasn't it attached?
Why do you avoid mentioning the effects of fire? Of differential expansion in a structure due to fire migration?
Why do you make no mention of creep?
Isn't 600 deg C hot enough for civil steel to creep when carrying a load?
Why do you believe that your story is NIST's "story"?
Your count of unanswered questions is at 37. Abuse doesn't count as an answer.
Classic jazzy lol I've only been comin to this site for a week or so but u could have put this up with no name and I would have bet money this was jazzy
Classic jazzy lol I've only been comin to this site for a week or so but u could have put this up with no name and I would have bet money this was jazzy
Oh, yes. One's bound to come up against a certain sort of person who thinks he is weathering a thread where all he has to do is to not answer questions.
I am thinking that you are probably about to find out why.
I thought the answer was rather obvious from post 1. Didn't you? Wasn't it a mystery we were all to solve together?
"Was it long, enough? Er, no, actually. By how much? Er, that much... Say that again? Er, that much... So it was too short by? Er, that much.... So NIST were wrong? Yes? And that means not right? Er, yes. Not right by how much? Er, that much... So what was it? Er, that much... Instead of what it would have been if they had been right? Can you repeat the question, please? What question? Was NIST right or wrong? No? Oh, then. That much... How accurate is your that much? According to our extensive calculations, NIST's that much was wrong by 93.719283746 % so our that much was 14.92175094 times better than their that much was. Drinks all round, eh? That went really well..."
Just for reference, I thought I would select the relevant portions of the NIST Report on the collapse of WTC 7 so that we may all see them
Points which Gerrycan and Boston are ignoring I have highlighted in red. Why the title of the thread is completely wrong (the expansion length of that particular girder isn't NIST's sole criterion at all) I have highlighted in purple:
NIST REPORT ES.3.
Eventually, the fires reached the northeast region of the building. The probable collapse sequence that caused the global collapse of WTC 7 involved the initiation of the buckling of a critical interior column in that vicinity. This column had become unsupported over nine stories after initial local fire-induced damage led to a cascade of local floor failures. The buckling of this column led to a vertical progression of floor failures up to the roof, and led to the buckling of adjacent interior columns to the south of the critical column. An east-to-west horizontal progression of interior column buckling followed, due to loss of lateral support to adjacent columns, forces exerted by falling debris, and load redistribution from other buckled columns. The exterior columns then buckled as the failed building core moved downward, redistributing its loads to the exterior columns. Global collapse occurred as the entire building above the buckled region moved downward as a single unit. This was a fire-induced progressive collapse, also known as disproportionate collapse, which is defined as the spread of local damage, from an initiating event, from element to element, eventually resulting in the collapse of an entire structure, or a disproportionately large part of it.
Factors contributing to the building failure were: thermal expansion occurring at temperatures hundreds of degrees below those typically considered in design practice for establishing structural fire resistance ratings; significant magnification of thermal expansion effects due to the long-span floors, which are common in office buildings in widespread use; connections that were designed to resist gravity loads, but not thermally induced lateral loads; and a structural system that was not designed to prevent fire-induced progressive collapse.
Even without the structural damage, WTC 7 would have collapsed from fires having the same characteristics as those experienced on September 11, 2001.
2.3. Page 19
Even though available images showing fires in WTC 7 did not allow the detailed description of fire spread that was possible for the WTC towers, there was sufficient information to derive general descriptions of fire ignition and spread on various floors of the building (NIST NCSTAR 1-9, Chapter 5). It must be kept in mind that the fire observations were based on images of the exterior faces, which provided little indication about the behavior of fires well removed from the exterior walls. It is likely that much of the burning took place beyond the views of the windows. Relatively little smoke was seen emanating from the windows on the north face, even when flames were observed, indicating that the hot combustion products were not exhausting through the nearest openings, but instead were passing through the building interior to other exits. The wind direction was from the north, and since there would have been office furnishings spread across the tenant spaces, some of the air would have penetrated to the building interior and supported combustion of the furnishings located there. Features of this interior burning were reconstructed from the computer simulations of the fires, as described in NIST NCSTAR 1-9, Chapter 9. Fires broke out on at least 10 floors of WTC 7, near the damaged southwest corner of the building (NIST NCSTAR 1-9, Chapter 5). They were typically observed as single floor fires, and observations supported a local fire origin on an given floor.
The early fire on each floor was small, probably involving a single cubicle or office. On the floors which were mostly furnished with clusters of cubicles (such as Floors 7 and 8), the initial fire spread would have been by flame contact with an adjacent cubicle within the cluster. Once a cluster was burning, a nearby cubicle, across an aisle, would have been ignited by thermal radiation from the flames. By the time this second cluster was fully involved, the prior cluster would have passed its peak burning rate. The path of the fires would likely have jumped from cluster to cluster, meandering toward the windows, toward the building core, or parallel to the façade. Eventually, the upper air layer over enough of the large open space would have become hot enough for the thermal radiation from the hot air to have heated and ignited multiple cubicles simultaneously, leading to faster fire growth.
Between roughly 2:00 p.m. and the collapse of WTC 7 at 5:20:52 p.m., fires were observed spreading on the 7th floor through the 13th floor, with the exception of the 10th floor. Since the collapses of the towers had resulted in the loss of city water that was the sole supply for the automatic sprinkler system on the lower 20 floors of WTC 7, these fires continued to spread unabated. All of these fires reached the northeast sector of the building between approximately 3:00 p.m. and 4:00 p.m. The intensities of the fires on the 11th, 12th, and 13th floors were higher than those on the 7th, 8th, and 9th floors because of the higher loading of combustibles and a larger burning area. There was also a small fire on the north side of the vacant 14th floor shortly before the collapse of the building. There was no visual evidence of fires on other floors, other than near the debris-damaged southwest corner of the building.
7th Floor
The fire on the 7th floor spread in a clockwise direction. Shortly after 2:00 p.m., there was a fire on the west side of the 7th floor, spreading north along the west face. The fire turned the northwest corner and by 3:00 p.m. was spreading east across the north face. Around 3:15 p.m., the fire, which had passed the midpoint of the north face, stopped and died down. About an hour later, the fire appeared a little fartherto the east, then died down by 4:40 p.m. Although no further images were available, it is likely that the fire continued to burn toward the east.
8th Floor
The 8th floor fire also spread clockwise. At about 3:40 p.m., a broad fire was first seen spreading east from the center of the north face. A few minutes later, there was a fire on the north end of the west face, suggesting that the fire had burned at the interior of the floor, initially bypassing the northwest corner, then burning back to that corner after the fire became established on the north face. The fire on the north face spread rapidly eastward, reaching the east face around 3:55 p.m., and then burned intensely on the east face. Soon after 4:00 p.m., the observable burning near the center of the north face had died down.
9th Floor
There were no indications of fire on the 9th floor until shortly before 4:00 p.m., when a small fire appeared on the west side of the north face. The fire grew rapidly and spread to the east, reaching the midpoint of the north face by around 4:10 p.m. Ten minutes later, the fire was halfway to the northeast corner, but by 4:38 p.m., there were only spot fires visible, located on the east side of the north face.
11th Floor
The fire on the 11th floor generally spread counterclockwise. Fire was first observed at 2:08 p.m. at the south end of the east face. Over the next 20 min, the fire spread slowly northward to the midpoint of the east face. Over the next two hours, images showed no burning. At 5:09 p.m., the fire reappeared near the center of the north face, spreading slowly to the west and not reaching the northwest corner when WTC 7 collapsed at 5:21 p.m. In the meantime, at 4:38 p.m., a fire appeared spreading east from the center of the north face, once again suggesting that the prior burning had progressed along the interior of the building before backtracking to combust furnishings near the perimeter. By 4:52 p.m., the observable flames in the area had died down.
12th Floor
The fire on the 12th floor followed a path similar to that of the fire on the 11th floor, but with different timing. Fire was first seen on the 12th floor at 2:08 p.m., toward the south end of the east face. Further south on this face, the window glass was still intact, indicating that this fire had burned in the building interior as it turned the southeast corner. By around 2:30 p.m., the visible flames had diminished, but the fire had spread both south into the southeast corner and north, reaching two-thirds of the way to the northeast corner. By 3:00 p.m., the fire had spread internally past the northeast corner and onto the north face. In less than 15 min, the fire simultaneously spread rapidly to the east to engulf the northeast corner of the floor and more slowly westward about one-third of the way across the north face. The fire continued spreading westward in starts and stops, approaching the northwest corner of the floor around 3:45 p.m. At around 5:00 p.m., the fire had reached the northwest corner.
13th Floor
Like the fires on the 11th and 12th floors, fire on the 13th floor also moved counterclockwise. Fire was seen at about 2:30 p.m. on the east side of the floor. Somewhat later, smoke and flames were coming from windows across much of the east face. Around 3:41 p.m., the fire had turned the northeast corner and was one-fourth of the way across the north face. Soon after 4:00 p.m., flames had reached at least to the midpoint of the north face; and at 4:38 p.m., the fires to the east had died down to the point where they could no longer be observed. Around 5:00 p.m., there was intense burning to the west of the center of the north face. A couple of minutes prior to the collapse of the building at 5:20:52 p.m., flames jetted from windows in the same area, indicating that there had been fire toward the interior of the floor.
14th Floor
A fire was seen briefly on the north face of the 14th floor, about halfway between the midpoint and the northeast corner, at 5:03 p.m. No fire was evident in images taken a few minutes before and a few minutes after this time.
2.4 THE PROBABLE COLLAPSE SEQUENCE
The following is the NIST account of how the fires in WTC 7 most likely led to the building's collapse.
The collapse of WTC 1 damaged seven exterior columns, between Floors 7 and 17 of the south and west faces of WTC 7. It also ignited fires on at least 10 floors between Floors 7 and 30, and the fires burned out of control on Floors 7 to 9 and 11 to 13. Fires on these six floors grew and spread since they were not extinguished either by the automatic sprinkler system or by FDNY, because water was not available in WTC 7. Fires were generally concentrated on the east and north sides of the northeast region beginning at about 3 p.m. to 4 p.m. As the fires progressed, some of the structural steel began to heat. According to the generally accepted test standard, ASTM E-119, one of the criteria for establishing the fire resistance rating for a steel column or floor beam is derived from the time at which, during a standard fire exposure, the average column temperature exceeds 538 °C (1000 °F) or the average floor beam temperature exceeds 593 °C (1100 °F). These are temperatures at which there is significant loss of steel strength and stiffness. Due to the effectiveness of the SFRM, the highest column temperatures in WTC 7 only reached an estimated 300 °C (570 °F), and only on the east side of the building did the floor beams reach or exceed about 600 °C (1100 °F). The heat from these uncontrolled fires caused thermal expansion of the steel beams on the lower floors of the east side of WTC 7, primarily at or below 400 deg C (750 deg F), damaging the floor framing on multiple floors.
The initiating local failure that began the probable WTC 7 collapse sequence was the buckling of Column 79. This buckling arose from a process that occurred at temperatures at or below approximately 400 °C (750 °F), which are well below the temperatures considered in current practice for determining fire resistance ratings associated with significant loss of steel strength. When steel (or any other metal) is heated, it expands. If thermal expansion in steel beams is resisted by columns or other steel members, forces develop in the structural members that can result in buckling of beams or failures of connections.
Fire-induced thermal expansion of the floor system surrounding Column 79 led to the collapse of Floor 13, which triggered a cascade of floor failures. In this case, the floor beams on the east side of the building expanded enough that they pushed the girder spanning between Columns 79 and 44 to the west on the 13th floor. (See Figure 1–5 for column numbering and the locations of girders and beams.) This movement was enough for the girder to walk off of its support at Column 79.
The unsupported girder and other local fire-induced damage caused Floor 13 to collapse, beginning a cascade of floor failures down to the 5th floor (which, as noted in Section 1.2.3, was much thicker and stronger). Many of these floors had already been at least partially weakened by the fires in the vicinity of Column 79. This left Column 79 with insufficient lateral support, and as a consequence, the column buckled eastward, becoming the initial local failure for collapse initiation.
Figure 2–2. Eastward buckling of Column 79, viewed from the southeast.
Due to the buckling of Column 79 between Floors 5 and 14, the upper section of Column 79 began to descend. The downward movement of Column 79 led to the observed kink in the east penthouse, and its subsequent descent. The cascading failures of the lower floors surrounding Column 79 led to increased unsupported length in, falling debris impact on, and loads being re-distributed to adjacent columns; and Column 80 and then Column 81 buckled as well. All the floor connections to these three columns, as well as to the exterior columns, failed, and the floors fell on the east side of the building. The exterior façade on the east quarter of the building was just a hollow shell.
The failure of the interior columns then proceeded toward the west. Truss 2 (Figure 1–6) failed, hit by the debris from the falling floors. This caused Column 77 and Column 78 to fail, followed shortly by Column 76. Each north-south line of three core columns then buckled in succession from east to west, due to loss of lateral support from floor system failures, to the forces exerted by falling debris, which tended to push the columns westward, and to the loads redistributed to them from the buckled columns. Within seconds, the entire building core was buckling.
The global collapse of WTC 7 was underway. The shell of exterior columns buckled between the 7th and 14th floors, as loads were redistributed to these columns due to the downward movement of the building core and the floors. The entire building above the buckled-column region then moved downward as a single unit, completing the global collapse sequence.
Gerrycan, would you care to point out the not-quite-relevant girder (is it beam K3004?) in this diagram?
Would you also to explain where the "other local fire-induced damage" is shown or mentioned in your presentation?
Would you like to argue why this data (which you don't present) has no effect on what you actually do present? That makes 40 unanswered questions.
Yes, Mick. I do wish I had put this on the first page of this thread.
Final temp = 1110F
Ambient temp = 70F
Delta T = 1040F (change in temp)
Coefficient = 0.00000802
Ambient Coefficient = 0.000006
Average Coefficient = 0.00000701
K3004 Beam = 640.69 inches
Expansion = 4.67 inches
Very interested to see what result you get. For NISTs story to make sense you are looking for a minimum of 6.25 inches.
Thanks for taking the time and interest in this. It is a topic that 'debunkers' have avoided like the plague. I am thinking that you are probably about to find out why.
Just in case anyone else would like to do the calculation, or the flow of this thread has been interrupted for them, this is where we are at, and this is a screenshot of the spreadsheet that has been used to illustrate the thermal expansion calculation for beam K3004 ~
Summary. After 4.0 h of heating, Column 81 had lost lateral support in the north-south direction at Floor
13, due to failure of the girders framing into Column 81. The girders between Columns 26 and 81 and
Columns 80 and 81 had buckled and the girder between Columns 79 and 44 had walked off the seated
connection at Column 79. In addition, all 4 bolts had failed at the seated connection at Column 79 on
Floor 14. Approximately one-half to three-quarters of the east floor beams had a connection damage
level of 0.75 to 1.0 on Floors 11, 12, and 14. All of the east floor beams, except for one, had failed on
Floor 13.
They give a lot more detailed description of this later in chapter 8, and the unseating the the 79->44 girder is attributed to the buckling failure of the beams after the initial failure of the shear studs. NOT the expansion of the beams, which only is required to break the shear studs.
NCSTAR 1-9 Page 352 (pdf 396)
The predicted response of the system is summarized in Table 8–2. The first failures observed were of the
shear studs, which were produced by axial expansion of the floor beams, and which began to occur at
fairly low beam temperature of 103 °C. Axial expansion of the girder then led to shear failure of the bolts
at the connection to Column 79; and, at a girder temperature of 164 °C, all four erection bolts had failed,
leaving that end of the girder essentially unrestrained against rotation. Continued axial expansion of the
floor beams pushed the girder laterally at Column 79, as shown in Figure 8–26, in which failed shear
studs and bolts were evident. When the beam temperatures had reached 300 °C, all but three shear studs
in the model had failed due to axial expansion of the beams, leaving the top flanges of the beams
essentially unrestrained laterally. Continued axial expansion of the girder caused it to bear against the face
of Column 79, generating large axial forces that led to failure of the bolts connecting the girder to Column
44. When the girder temperature had reached 398 °C, all four erection bolts at Column 44 had
failed, leaving the girder essentially unrestrained against rotation at both ends. After failure of the erection
bolts in the seat at Column 44, continued axial expansion of the floor beams pushed the girder laterally,
where it came to bear against the inside of the column flange. Axial compression then increased in the
floor beams, and at a beam temperature of 436 °C, the northmost beam began to buckle laterally.
Buckling of other floor beams followed as shown in Figure 8–27 (a), leading to collapse of the floor
system, and rocking of the girder off its seat at Column 79 as shown in Figure 8–27 (b). The collapse
process took time to occur in the LS-DYNA analysis, during which the temperatures had ramped up to
their maximum values in the simulation.
Thanks to Gerrycan for this thread and the research. Very well done, and you have the patience of Job.
People like you are making a huge difference. I'm forwarding links to this thread with every opportunity that allows.
Maybe Ben Swann heard you!
The video on this link was just released today. Despite the forum posting software saying Vimeo is supported, the link will not embed.
Here is the just released Ben Swann video on "Rethinking 911"
Thanks to Gerrycan for this thread and the research. Very well done, and you have the patience of Job.
People like you are making a huge difference. I'm forwarding links to this thread with every opportunity that allows.
This is not a difficult sum. What distance go you get for the expansion? It will help me to answer your latest post in a far clearer way. Do you need more detail on the figures?
This is not a difficult sum. What distance go you get for the expansion? It will help me to answer your latest post in a far clearer way. Do you need more detail on the figures?
Mick, I would be willing to debate you live on this issue, I don't know if this site has the facility to do that, but if not there is actually a live room elsewhere that would be available for this. Live audio and text where you can have administrator rights also. You use the following table:-
Do you seriously think that it is possible for the beam to increase in temperature by 497C in less than 1.5s and the girder to increase in temperature by 411c over the same time period? Pure fiction from NIST here. Even given such an increase, these elements would still not fail in the manner described by NIST. If they had confidence in this model they would release the input data for it and allow it to be checked, they steadfastly refuse to do so on the grounds that it may jeopardize public safety. Nonsense. If buildings could fail this way, such a release would enhance public safety. The truth of it is that NIST started their investigation with a conclusion, and that just is not how science and engineering analysis is done at all. The above table illustrates their unwillingness to submit to the scientific method. A finite element analysis has been done independently of NIST and has shown their nonsense to be just that, nonsense. The above has substantial elements failing on the girder at UNDER 90C, and on the beam at 103C - can't happen.
You do realise that this table is referring to an ANSYS model don't you? Which DID NOT include the proper elements and was released years before their erratum statement, which you quoted yourself in this thread? i will reply to your most recent post shortly.
There's no real live facility other than the "chat" on the front page. But I can't do engineering in real time anyway. I like to take time to check things, and read the material. Live debates are largely pointless as they don't produce things that can be reference.
The point of the above is that NIST did not claim the beams expanded by the amount you say they claim. Why don't you just explain otherwise?
I'm not sure what the Time column refers to. I shall investigate.
The time was just simulation time not real world heating time. The gravity loading and then heating was simulated over compressed times to allow for higher resolution.
To avoid dynamic effects, the gravity loading was ramped up smoothly over a period of 1 s, as shown in
Figure 8–24. Ramping of the temperatures for the beams and the girder then commenced at 1.1 s, as
shown in Figure 8–25, leveling off at temperatures of 600 °C for the beams and 500 °C for the girder at
2.6 s. These temperature histories were prescribed uniformly for all nodes of the beams and the girder,
respectively. The material model for the steel beams and girders incorporated temperature dependence in
the stress-strain behavior and accounted for thermal expansion. No thermal expansion or material
degradation was considered for the slab, as the slab was not heated in this analysis.
35. (added 6/27/12) What was the purpose of the partial floor model of the northeast section of WTC 7 (Section 8.8 of NIST NCSTAR 1-9) in the investigation of the collapse of WTC 7? How were these analyses used in the final WTC 7 16-story model? Were there any discrepancies between the results of the partial floor model and the 16-story model?
The detailed finite element model of the partial (northeast) floor framing was developed to evaluate its response to elevated temperatures and to confirm which failure modes needed to be accounted for in the 16-story ANSYS model, i.e., which failure modes were possible. This detailed model consisted of shell elements to model the steel wide flange sections and plates and the concrete floor slab, and the model was capable of capturing both local and overall member buckling. Shear studs were modeled explicitly as were bolts.Contact interfaces were employed between different components to model, for example, the girder resting on the seats at both column 44 and column 79. Temperature-dependent material properties were defined and appropriate boundary conditions were prescribed. Gravity loads were applied to represent service loads and uniform, monotonically increasing temperatures were applied to the floor beams and girder, to cause both thermal expansion and degradation of mechanical properties.
Results confirmed that possible failure modes included: lateral-torsional buckling of the wide flange shapes, bolt shear failure, stud shear failure, and the potential for the girder to walk off its seat at either column.
The possible failure modes identified in the LSDYNA analysis (explicit finite element solution) were then incorporated into the 16-story ANSYS analysis (implicit finite element solution) through:
(1) Selection of appropriate ANSYS elements that allowed, for example, member buckling,
(2) Specially formulated connection elements that captured connection component behavior such as flexibility, slip and gap closure, and failure modes such as bolt failure, weld failure, block shear and walk off, and
(3) Special-purpose scripts written in ANSYS Parametric Design Language (APDL) that interrogated analysis results at each step to
a) determine if a failure criteria such as walk-off was met, and
b) modify the model as necessary to account for the failure that was detected.
Differences between the results of the partial floor model and the 16-story model are to be expected.Reasons for these differences include:
(1) While the partial floor model used a simplified thermal loading scenario, in which the beam and girder temperatures were uniform and were increased monotonically (see Figure 8-25 of NIST NCSTAR 1-9), the 16-story ANSYS model used computed temperatures based on fire dynamics and thermal calculations.
(2) While the columns in the partial floor model were fixed against lateral displacements, the columns in the 16-story model were allowed to move laterally based on the response of the structural system.
(3) While the partial floor model applied rotational and in-plane translational constraints along the west and south boundaries of the floor slab, the 16-story model represented the entire slab for all floors.
Let me roll back there - being a bit overenthusiastic: The discussion of the ANSYS model says
Walk off occurred when beams that framed into the girders from one side thermally expanded and the
resulting compressive forces in the beams pushed laterally on the girder from one side, sheared the bolts
at the seated connection, and then continued to push the girder laterally until it walked off the bearing
seat. A girder was considered to have lost vertical support when its web was no longer supported by the
bearing seat. The bearing seat at Column 79 was 11 in. wide. Thus, when the girder end at Column 79
had been pushed laterally at least 5.5 in., it was no longer supported by the bearing seat. Additional
factors that contributed to this failure were the absence of shear studs on the girders that would have
provided lateral restraint and the one-sided framing of the northeast corner floor beams that allowed the
floor beams to push laterally on the girder due to thermal expansion.
Which seems inconsistent with the LSDYNA simulation results. I suspect that the difference is accounted for by column movement.
Let me roll back there - being a bit overenthusiastic: The discussion of the ANSYS model says
Walk off occurred when beams that framed into the girders from one side thermally expanded and the
resulting compressive forces in the beams pushed laterally on the girder from one side, sheared the bolts
at the seated connection, and then continued to push the girder laterally until it walked off the bearing
seat. A girder was considered to have lost vertical support when its web was no longer supported by the
bearing seat. The bearing seat at Column 79 was 11 in. wide. Thus, when the girder end at Column 79
had been pushed laterally at least 5.5 in., it was no longer supported by the bearing seat. Additional
factors that contributed to this failure were the absence of shear studs on the girders that would have
provided lateral restraint and the one-sided framing of the northeast corner floor beams that allowed the
floor beams to push laterally on the girder due to thermal expansion.
Which seems inconsistent with the LSDYNA simulation results. I suspect that the difference is accounted for by column movement.
Good on you for spotting that and having the integrity and honesty to post it before I did. Many would not do that. However, as per your analysis at the end "I suspect that the difference is accounted for by column movement". What we are talking about here is the event that allegedly left the column unsupported (which is nonsense in itself) so how can it possibly move in the model before it was unsupported? Bottom line, NIST will not release their input data because they had to fudge the inputs to induce the failure that they wanted to happen because it suited their mistaken hypothesis.
So I am now presuming that we agree that the 'walk off' that NIST suppose is impossible, and that the original point of this thread is now proven.
NIST say :
"Thus, when the girder end at Column 79 had been pushed laterally at least 5.5 in"
YOU said :
"640.69*.00000701*1040 = 4.67, but like I said, NIST never claims a longer expansion" <Emphasis added, you have now corrected this. Respect.
I say:
"NIST got the initiating event totally wrong for WTC7 and need to have this re investigated"
I think we agree now that NIST have not given a realistic account for what happened to WTC7 to cause it to collapse. Their analysis is woeful, it does not stand up to scrutiny, and the erratum statements that they have released since, only dig them into a deeper hole, because they make thermal expansion around column 79 an impossibility to the extent that they say that it happened in order to initiate the collapse of the building.
Do we need to go further with this particular thread?
Yes, I think we do. NIST have some conflicting sounding statements, but they still have the one model (the partial floor model) in which the beams did NOT push the girder off its seat, and it still failed. This demonstrates that it could have failed. Certainly all the beam shear studs and the clip and seat bolts would have failed. This model was the the more detailed modelling of the connections than the larger 16-floor model.
And the limited expansion of the beams (which I accept for the sake of argument, but I'm not 100% convinced as to the precise limits) might not be as limiting as you think
The failures in the partial floor model is a complex three dimensional buckling distortion, not a simple linear push.
Consider this thought experiment
Now in the simple case, if K3004 were to push 4.6" then that's not far enough (6" needed) however there's at least a couple of scenarios where it might be, depending on the order of heating of the five beams (K, C, B, A, G) And the Girder (R, for convenience)
Take a purely imaginary outside case. K expands first (roughly), breaking the C79-R connections. C, B, A, do likewise. Now if we (for now) ignore K,C, B, A, and imagine for the sake of argument that the R pivots around C44.
Under this very simplistic model an expansion one inch of G would result in motion of the end of the girder at C78 by of approximately eight inches.
Now that's not realistic. However nor do I think a simplistic model of KCBAG all expanding at the same rate is realistic. They would have expanded at different rates, and the combination of those expansions, with perhaps some pivoting, and distortion of the girder itself, would be what caused the girder to be unseated on C79.
NIST describes that the C79 connection was unseated by the girder walking off. They ascribe this to the five beams expanding. They might not be wrong, and they do not (I believe) claim that it was simply due to the expansion of K3004.
Ideally we'd like to see the graph of the positions of the endpoints of all the beams and girders involved. Unfortunately that's unlikely. However the end result still seems plausible.
And to expand upon my thought experiment a little. If we assume pivoting around C44, then an expansion of an inch in C is (by blueprint measurements), about 1.4 inches at C17. With larger values for B, A and G. So a 4.67 motion for CBAG would result in the C79 end wanting to move at least 1.4x4.67 = 6.5"
The objections here are that the C44 connection would break, not pivot (it would, but then wedge, and pivot). And that the lower beams (K, C) would retard the rotation caused by the upper beams (but how much, if they have been heated to sagging point).
But the overall point I'm making is that it's not as simple as you make out. The Girder is going to twist in some way, the beams will alternately expand and sag, the expansion of some beams might effective pivot against other beams, and/or C44.
I agree totally with this. I think that such a debate would be a rare event, as I feel sure that it would be an honest search for truth rather than the usual point scoring exercise that such debates usually descend into. This is a testament to Micks tenacity and providing he brought the kind of integrity that he has shown in this thread, such a debate would perhaps be a first, and would present an example of what the way forward for this whole issue should be. This is also a hot topic at the moment, as shown by Tony on the TV clip in xenons post above. When we sat down with Tony and showed him the stifffener plates he referred to them as a 'gamechanger'. He was 100% correct.
Just for reference, here's the C44 connection (DWG 9102). As you can see the end of the girder would pivot after very little motion after the connection fails. But would likely still be supported by the seat.
I agree totally with this. I think that such a debate would be a rare event, as I feel sure that it would be an honest search for truth rather than the usual point scoring exercise that such debates usually descend into. This is a testament to Micks tenacity and providing he brought the kind of integrity that he has shown in this thread, such a debate would perhaps be a first, and would present an example of what the way forward for this whole issue should be. This is also a hot topic at the moment, as shown by Tony on the TV clip in xenons post above. When we sat down with Tony and showed him the stifffener plates he referred to them as a 'gamechanger'. He was 100% correct.
Yes, I think we do. NIST have some conflicting sounding statements, but they still have the one model (the partial floor model) in which the beams did NOT push the girder off its seat, and it still failed. This demonstrates that it could have failed. Certainly all the beam shear studs and the clip and seat bolts would have failed. This model was the the more detailed modelling of the connections than the larger 16-floor model.
And the limited expansion of the beams (which I accept for the sake of argument, but I'm not 100% convinced as to the precise limits) might not be as limiting as you think
The failures in the partial floor model is a complex three dimensional buckling distortion, not a simple linear push.
Consider this thought experiment
Now in the simple case, if K3004 were to push 4.6" then that's not far enough (6" needed) however there's at least a couple of scenarios where it might be, depending on the order of heating of the five beams (K, C, B, A, G) And the Girder (R, for convenience)
Take a purely imaginary outside case. K expands first (roughly), breaking the C79-R connections. C, B, A, do likewise. Now if we (for now) ignore K,C, B, A, and imagine for the sake of argument that the R pivots around C44.
Under this very simplistic model an expansion one inch of G would result in motion of the end of the girder at C78 by of approximately eight inches.
Now that's not realistic. However nor do I think a simplistic model of KCBAG all expanding at the same rate is realistic. They would have expanded at different rates, and the combination of those expansions, with perhaps some pivoting, and distortion of the girder itself, would be what caused the girder to be unseated on C79.
NIST describes that the C79 connection was unseated by the girder walking off. They ascribe this to the five beams expanding. They might not be wrong, and they do not (I believe claim that it was simply due to the expansion of K3004.
Ideally we'd like to see the graph of the positions of the endpoints of all the beams and girders involved. Unfortunately that's unlikely. However the end result still seems plausible.
The fact remains that NIST claimed to have heated up these elements in the manner shown in your earlier post ie, to 500 and 600C within a couple of seconds. Their claimed output is impossible. This is totally unrealistic.
We considered the hypothetical you are talking about re column 44. I imagine you are scrutinizing that just now. Perhaps I can save you some time there - here's the dimensions of the column :-
Here's how it connects to the girder, with dimensions added :-
And here's the connection with the kip ratings :-
Getting back to the beams, as you can see in the drawing E12/13 and also on the spreadsheet, they would expand less and actually tend to hold the girder spanning column 79 and 44 in place, as I think you can see.
We went through every 'what if' scenario we could think of in researching this information, and column 44 played a major part in that analysis.
I disagree, Tony has always struck me as being a man of integrity, who like myself, would rather not be correct about his analysis of what happened on 911. The recent paper that he, and other released on buckling moments in wide columns is elegant in its presentation and rich in content. Very thought provoking, but more applicable to the towers obviously. Tonys willingness to engage and openness in the way he does so mean that he is often unfairly maligned by debunkers. His steadfast determination to continue to explore the 911 issue in this open and engaging way is a credit to him and those for whom he speaks.
Anyway, back to this girder.....................
The fact remains that NIST claimed to have heated up these elements in the manner shown in your earlier post ie, to 500 and 600C within a couple of seconds. Their claimed output is impossible. This is totally unrealistic.
Thanks to Gerrycan for this thread and the research. Very well done, and you have the patience of Job.
People like you are making a huge difference. I'm forwarding links to this thread with every opportunity that allows.
Maybe Ben Swann heard you!
The video on this link was just released today. Despite the forum posting software saying Vimeo is supported, the link will not embed.
Here is the just released Ben Swann video on "Rethinking 911"
The fact remains that NIST claimed to have heated up these elements in the manner shown in your earlier post ie, to 500 and 600C within a couple of seconds. Their claimed output is impossible. This is totally unrealistic.
No they don't, that's just the time they used for the simulation. The expansion and deformation are essentially instantaneous (i.e. when the beam gets to that temperature, then it's at that length), so it makes no difference. And that was just for the the partial floor model.
Of coure it makes a difference, steel conducts and there is 40,000 tons of it to do so in WTC7. ANSYS is capable of a far more realistic simulation than this, and NIST claim that each run on their model took 8 weeks to process, so they clearly had the time to do a more in depth analysis. Maybe we should start a new thread. The assertion that I made at the start of this has been proven.
Of coure it makes a difference, steel conducts and there is 40,000 tons of it to do so in WTC7. ANSYS is capable of a far more realistic simulation than this, and NIST claim that each run on their model took 8 weeks to process, so they clearly had the time to do a more in depth analysis. Maybe we should start a new thread. The assertion that I made at the start of this has been proven.
It makes no difference once it has arrived at a particular temperature - then it will be in a particular state. The six second simulation just speeds things up.
You didn't make an assertion at the start of the thread.
Sorry, i meant to say, the assertion that i made via the content of the video presentation that i alluded to in the initial post of this thread has been proven. The steel would conduct the heat away over time, and i also think that 100 degree of difference between the beams and the girder is unrealistic. As is the failure to heat up the concrete, which sets up a differential thermal expansion, putting an unrealistic force on the studs. Also, the failure to include the floor pan is just preposterous. The difference that heating the steel up gradually, as would happen in the real world is that the steel, being highly conductive would wick the heat away, as it conducts.
Just an observation, I bet you know a hell of a lot more about column 79 than you did a week ago lol. I really do respect the way you have been willing to take this info on board Mick.
Sorry, i meant to say, the assertion that i made via the content of the video presentation that i alluded to in the initial post of this thread has been proven.
What was that exactly? Just the "beams would not expand enough", or a more general "NIST were wrong" of "collapse is impossible" point?
Not trying to be snarky, but it would be best to simply state what assertion you think has been proven.
The steel would conduct the heat away over time, and i also think that 100 degree of difference between the beams and the girder is unrealistic. As is the failure to heat up the concrete, which sets up a differential thermal expansion, putting an unrealistic force on the studs. Also, the failure to include the floor pan is just preposterous. The difference that heating the steel up gradually, as would happen in the real world is that the steel, being highly conductive would wick the heat away, as it conducts.
I believe they heated the concrete in the full sized simulations. This was just a mode-of-failure simulation to see what would happen in detail with the steel heating.
Plus it's very visual, and JRE is mostly a podcast format.
