9/11...... de officiële versie!

quote:

Mmz oke http://nl.wikipedia.org/wiki/11_september_2001 hij heeft ze niet direct opgeëist maar indirect ofzo. Dan valt dat argument ten dele maar toch vind ik het nog steeds onzin

quote:

Op dinsdag 31 mei 2005 13:58 schreef -Beestje- het volgende:

[..]

het gewicht wordt dan vooral opgenomen door de kolomen direct naast de ontbrekenden
totdat het zover gaat dat de top begint te kantellen en aan de andere kant van het buigpunt ook trekkrachten gaan werken (niet lang want op dat moment gaat het heel snel )

maar als ik de opmerking hierergens boven las hebben ze hier nooit rekening mee gehoeden of kunnen houden omdat ze verwachte dat een vliegtuig er op een zelfde manier door heen zou gaan als een brood door en snijmachine

quote:

Op dinsdag 31 mei 2005 16:15 schreef Wombcat het volgende:
Lijkt me trouwens ook logisch dat je er niet direct rekening mee houdt dat er een airliner je gebouw binnenvliegt. Ik vraag me zelfs af of je er op kunt bouwen dat als het gebeurt de boel overeind blijft staan. Zal vast wel kunnen, maar tegen welke kosten?

quote:

Lijkt me trouwens ook logisch dat je er niet direct rekening mee houdt dat er een airliner je gebouw binnenvliegt.

quote:

Op dinsdag 31 mei 2005 16:15 schreef Wombcat het volgende:

[..]

Omdat dat zo snel gaat, krijg je vervolgens toch het effect dat het (vrijwel) rechtstandig in elkaar stort.

Lijkt me trouwens ook logisch dat je er niet direct rekening mee houdt dat er een airliner je gebouw binnenvliegt. Ik vraag me zelfs af of je er op kunt bouwen dat als het gebeurt de boel overeind blijft staan. Zal vast wel kunnen, maar tegen welke kosten?

quote:

Op dinsdag 31 mei 2005 16:33 schreef merlin693 het volgende:

[..]

Maar er is rekening mee gehouden tijdens het ontwerpen ! ? of begrijp ik je nu verkeerd ?

quote:

Towers' Design Parameters
Twin Towers' Designers Anticipated Jet Impacts Like September 11th's


The above graphic from FEMA's report shows the sizes of a 707 and a 767 relative to the footprint of a WTC tower. 2 Although a 767 has a slightly wider body than a 707, its overall size, weight, and fuel capacity are very similar to a 767-200 -- the type of jet that Flight 11 and Flight 175 were.

property Boeing 707-340 Boeing 767-200
fuel capacity 23,000 gallons 23,980 gallons
max takeoff weight 328,060 lbs 395,000 lbs
empty weight 137,562 lbs 179,080 lbs
wingspan 145.75 ft 156.08 ft
wing area 3010 ft^2 3050 ft^2
length 152.92 ft 159.17 ft
cruise speed 607 mph 530 mph

Given the differences in cruise speeds, a 707 in normal flight would actually have more kinetic energy than a 767, despite the slightly smaller size. Note the similar fuel capacities of both aircraft. The 767s used on September 11th were estimated to be carrying about 10,000 gallons of fuel each at the time of impact, only about 40% of the capacity of a 707.

Like all Skyscrapers, the Twin Towers were Over-Engineered


One aspect of engineering that is not widely understood is that structures are over-engineered as a matter of standard practice. Steel structures like bridges and buildings are typically designed to withstand five times anticipated static loads and 3 times anticipated dynamic loads. The anticipated loads are the largest ones expected during the life of the structure, like the worst hurricane or earthquake occurring while the floors are packed with standing-room-only crowds. Given that September 11th was not a windy day, and that there were not throngs of people in the upper floors, the critical load ratio was probably well over 10, meaning that more than nine-tenths of the columns at the same level would have to fail before the weight of the top could have overcome the remaining columns.

Frank A. Demartini, on-site construction manager for the World Trade Center, spoke of the resilience of the towers in an interview recorded on January 25, 2001.

The building was designed to have a fully loaded 707 crash into it. That was the largest plane at the time. I believe that the building probably could sustain multiple impacts of jetliners because this structure is like the mosquito netting on your screen door -- this intense grid -- and the jet plane is just a pencil puncturing that screen netting. It really does nothing to the screen netting.

Demartini, who had an office on the 88th floor of the North Tower, has been missing since the 9/11/01 attack. 3


--------------------------------------------------------------------------------
References

1. Towers collapse shocks engineers, MedServ, 9/11/01 [cached]
2. Chapter 2: WTC 1 and WTC 2, WTC Building Performance Study,
3. Painful Losses Mount In the Construction 'Family', construction.com, 10/1/01 [cached]

quote:

Op dinsdag 31 mei 2005 16:43 schreef merlin693 het volgende:

the critical load ratio was probably well over 10, meaning that more than nine-tenths of the columns at the same level would have to fail before the weight of the top could have overcome the remaining columns.

quote:

Given that September 11th was not a windy day, and that there were not throngs of people in the upper floors, the critical load ratio was probably well over 10, meaning that more than nine-tenths of the columns at the same level would have to fail before the weight of the top could have overcome the remaining columns.

quote:

Op dinsdag 31 mei 2005 17:39 schreef merlin693 het volgende:
ik denk dat je hier iets niet goed leest , ze hebben het juist over dat de belasting zo laag was dat er 9 kolommen konden falen voordat de gewicht ratio de top zou doen omplappen !
[..]

quote:

Op dinsdag 31 mei 2005 17:54 schreef merlin693 het volgende:
Maar beredeneer je nu dus eigenlijk dat kerosine helemaal niet nodig was om het gebouw te laten instorten , en die verklaring dus overbodig is ?

quote:

Op dinsdag 31 mei 2005 20:51 schreef merlin693 het volgende:
ah ok...... dan begrijp ik je positie !

hier een link naar rence...ja ik weet maar vaak linken/copyen ze ook valide raporten/verslagen

http://www.rence.com/general65/911h.htm

quote:

Op dinsdag 31 mei 2005 18:27 schreef UncleScorp het volgende:
Aaaaah die kerosine ...
Bij de 2e crash vloog het merendeel van de kerosine naar buiten.

quote:

Op dinsdag 31 mei 2005 16:03 schreef ee-04 het volgende:
Hoeveel mensen zouden daar bij betrokken zijn? Toch zeker honderen lijkt mij. Dat is een veel te groot risico, dan klapt er altijd wel iemand open met spijt of weet ik veel wat. Dat is voor mij al genoeg bewijs tegen zo'n samenzweringsgedachte.

En waarom zou je het doen? Waarom zou Bush dat toelaten? En kom niet met dat olie verhaaltje want je maakt mij niet wijs dat al die mensen daar aan gaan meewerken voor wat olie. En waarom zou Bin Laden het dan niet bekend maken dat Bush en vrienden er zelf iets mee te maken hebben? Hij blijft het zien als zijn aanval.

quote:

Op dinsdag 31 mei 2005 18:27 schreef UncleScorp het volgende:
Aaaaah die kerosine ...

Het was toch idd de kerosine die het staal doen doorbuigen heeft ?
Ondanks dat kerosinebrand eigenlijk onvoldoende warmte daarvoor produceert, wat dan weer uitgelegd werd dat het vuur versterkt werd door allerlei materialen in het gebouw .
Anderen merkten op dat er veel zwarte rook te zien was wat dan weer zou wijzen op onvoldoende zuurstof en dus een slecht-brandend vuur, en dus wss ook niet genoeg hitte.
Bij de 2e crash vloog het merendeel van de kerosine naar buiten.
De brandweer had toch ook ergens gezegd dat ze het vuur wel onder controle zouden kunnen krijgen.
En tenslotte was ground zero nog dagen erna meer dan normaal gloeiend heet.

Maar het kan idd ook met die kolommen te maken hebben ...
Dan vraag ik me eigenlijk af of dat dan niet sneller gebeurd zou zijn ? De beschadigingen aan de steunkolommen waren er vanaf impact, het staal is pas later door het vuur beginnen doorbuigen. Of is het gewoon een toevallige timing van de 2 ? En dan ook voor de 2 torens ondanks verschillende beschadigingen toch beiden ingestort ?

quote:

Op woensdag 1 juni 2005 11:07 schreef Sapientiea het volgende:
Vergeet het WTC7 even niet. Die storte ook in omdat er brand was uitgebroken, maar hier was geen vliegtuig ingestort en dus geen kerosine.

quote:

Op woensdag 1 juni 2005 11:18 schreef UncleScorp het volgende:

[..]

Het argument voor wtc7 is dat er dieseltanks stonden opgeslagen in het gebouw ...

quote:

Op woensdag 1 juni 2005 13:21 schreef Chewie het volgende:

[..]

En wat is daar vreemd aan?

quote:

Op woensdag 1 juni 2005 13:24 schreef Sapientiea het volgende:
Nou dat er dus drie gebouwen instorten op een dag waarvan bij alle drie de oorzaak van het instorten bezine/kerosine is.
Beetje raar dat WTC7 instort als er maar 3 kleine vuurtjes te zien zijn. Als de dieseltanks het gevolg zijn dat had ik veel veel rook verwacht en veel brand enzo......

quote:

Op woensdag 1 juni 2005 13:27 schreef UncleScorp het volgende:

[..]

wtc7 zou ook serieus beschadigd geweest zijn door vallende brokstukken van de andere wtc's, wat echter niet op de beschikbare foto's te zien zou zijn ...

quote:

Op woensdag 1 juni 2005 13:24 schreef Sapientiea het volgende:

[..]

Nou dat er dus drie gebouwen instorten op een dag waarvan bij alle drie de oorzaak van het instorten bezine/kerosine is.
Beetje raar dat WTC7 instort als er maar 3 kleine vuurtjes te zien zijn. Als de dieseltanks het gevolg zijn dat had ik veel veel rook verwacht en veel brand enzo......

quote:

While the jet fuel from the aircraft burned off within the first few minutes, the fire temperatures attained in the twin tower was not significantly different from other building fires. However, the fire intensity and heat output generated in the twin tower fires was very much higher that typical building fires. The intense fires ignited by jet fuel, loss of fire defence mechanism, damaged fire proofing and the stressed state of the structural system were the main factors that contributed tot the collapse of the towers.

quote:

|the massive impacts from each of the aircraft resulted in severe strucutral damage at several floor levels in each tower. However the structures remained standing, at least initially, despite this heavy but localized damaged. The subsequent, intense fires that followed further weakened the alreadye damaged structure, resulting in the collapse of the floors, initiated at the floor with the wost fire conditions. The impact load of the collapsing floors on the structure below started a progressive collapse and resulted in the complete collapse of the towers

quote:

Both WTC 1 and WTC 2 buidlings were designed to withstand the accidental impact of a Boeing 707 jet aircraft, which was the state of the art aircraft at the time of construction. However, the original design did not account for the fuel carried by such aircraft

quote:

The fire protection system features in each of the towers included sprinklers, smoke control systems, fire detection systems, notification systems and structural fire protection

quote:

The impact of both aircraft resulted in severe structural damage at several floors in each tower. However the structures remained standing, at least initially, despite this heavy but localized damage. Immediately after impact, jet fuel ignited on several floors. The intens fires that followed further weakened the already damaged structure, resulting in the partial collapse of floors, initiated at the floors with the worst fire conditions. This vertical impact load caused failure on underlying multi-floor segments of the tower, in which the failure of the connectiions of the floor carrying trusses is either accompanied by buckling of core colums or overall buckling of the frame tube, probably spanning the heigt of many floors. The impact load of the collapsing floors on the structure below started a progressive collapse and resulted in the complete collapse of the towers

quote:

The impact of the planes and the ensuing fires were the most two crucial factors that led to the collapse od the twin towers. While the two towers suffered significant structural damages fromthe impact of the planes, they withstood the impact. Based on the preliminray analysis FEMA report the conclusion is that in the absence of a severe loading event, the twin towers could have remained standing in a damaged state until subject to significant additional load. Hower, the severe fires that followed the impact brought down the twin towers at different intervals- 59 and 82 minutes respectively following impact. Thus the fire issues played a major role in the collapse of teh twin towers.Some of these issues are discussed in the following section

quote:

The impact of aircraft on the north face of WTC 1 and on the corner of the south and east of WTC 2 caused massive damage to the sturctural system at the impacted floors. The extent of damage was much higher in the case of WTC 2 where core colums were destroyed in the south and east faces. This is because the impact of the jet was on the corner and the speed of the aircraft was higher. The aircrafts penetrated in the central core and debris travelled completely through the structure, thereby causing damage to colums in the central core as well. In all, up to half of thecolums along the north building face appear to have been destroyed over portions of a six-storey range in the case of the north tower. Partial collapse of floors at the impacted levels occured in both WTC 1 and 2.

quote:

The twin towers withstood the impact (...). This enabled the structure to redistribute loads tot he remaining structural elements and overcome immidiate collapse. However after redistribution of loads, the utilisation ratio in some of the colums, close to the impact zone, reached unity. Hence, after the impact the structural members were in a highly-stressed state. In the case of WTC 2 the stressed state of structural elements was much more severe that WTC 1 due to larger impact damage

quote:

Each of the aircraft had about 10,000 gallons of jet fuel aboard. About 25 % of this was consumed in the initial blast and rsulting fireball. Another 25 % of the fuel is believed to have flowed down through elevators and utility shafts in the buildings. The remaining 50% of the fuel burned of within the first few minutes (5 to 8 minutes) after impact. As the jet fuel burned, the resulted heat ignited office contents, and combustible airfraft contents, at several impacted floors. Therefore, jet fuel, though burned off in the first minutes acted as a catalyst in igniting the combustible materials and in genereating massive fires at several floors.
The large quantity of jet fuel that spread across several floors of the building ignited mcu of the building and aircraft contents. This caused simultaneous fires across several floors at the same time. This generated fire conditions significantly more severe than those anticipated in typical building fires. The maximum fire temperatures attained in the WTC fires were in the range of 1,000 to 1,100 Celsius. These temperatures were not significantly different from other typical office building fires. However the rise in temperatures was much faster than those in typical building fires and represented typical hydrocarbon fires with temperatures reaching about 800 degrees in the first 3 to 4 minutes.
However, the fire size and heat output in the WTC fires was much higher that that of typical office building fires. The heat output generated fro WTC fires was about 2-5 GW and comparable to the power output produced by a large commercial power generator station.

quote:

Steel-framed buildings depend on fire proofing for its ability to resist the impact of fire. The durability (adhesion and vohesion) of sprayed fiber and to a lesser extent, cementatious materials is a problem when subjected to significant impact loads. In the twin towers the impact of the aircraft mechanically damaged much of the spray-applied fire protection, to an extent tthat much of the steel in the immidiate fire area was unprotected. The intense fires on several floors weakend the bare steel

quote:

In the case of the twin towers, the severe fire conditions overcame the buildings fire defences considerably faster than expected. Due to the very high intensity of the fires, sprinklers, the first level of defence, were either ineffective or non-operational. Active fire fighting, the second level of defence, could not be undertaken effectively since the fires weer at higher floor levels. |Further the impact of the planes had caused significant damage to fire proofing, the third level of defence. Added to this was the status of structural members at impacted floors that were stressed to their full capacity. Therefore the failure of the three basic fire defence mechanisms significantly contributed to the collapse of the towers

quote:

Steel loses its strenght and stifness when subjected to high temperatures. A typical steel structural member loses its load-carrying capacity )or about 50% of its original strength) at 538 Celsius when exposed to a standard fire.

quote:

Contrary tot many early media reports, the steel did not melt.

quote:

Summary
The fire resistance issues played a major role in the collapse of the3w twin towers. The impact of aircraft caused massive damage to the structural system at impacted floors and left the structural members that withstood the impact in a highly-stressed state. the hige amount of jet fuel from the aircraft, though burned off within the first few minutes, ignited office and aircraft contents, that resulted in massive fires. the fire intensity and heat outpur generated fro these fires was much more severe than typical building fires; however resulting fire temperatures were not significantly different from office fires. The loss of fire defence mechanisms, included damaged fire protection, further contributed to weakenig the structural members. the intense heat from the fires attacked the structural system and over a period of time, resulted in sufficient additional damage to the structural system to initiate a progressive sequence of failures that eventually culminated in the total collapse of both towers.

quote:

Op zondag 5 juni 2005 10:33 schreef OpenYourMind het volgende:
Goede posts Wombcat

Dit is dan ook het punt van discussie en het punt waarom believers en non-believer het nooit met elkaar eens zullen worden. Beide partijen kunnen dit soort rapporten maken en uitbrengen met evenveel geloofwaardigheid maar zonder dat er echt bewezen kan worden of het klopt. Je houdt slechts twee partijen die discusieren over twee tegenover elkaar staande theorieen.

Dit blijft meer een geloofskwestie totdat iemand dit onomstotelijk kan bewijzen door een grootschalige reconstructie uit te voeren. Dit is ook de reden dat ik mij hier nauwelijks mee bezig houd. Simpel omdat je hier geen uitsuitsel over kan geven en het een oneindige welles, nietus discussie is. Daarbij leid het ontzettend af van de grote stapel bewijzen die er op wijzen dat 9/11 geen intelligence failure is maar dat er tenminste meegewerkt is om 9/11 te laten gebeuren.

quote:

Op zondag 5 juni 2005 11:39 schreef Wombcat het volgende:
Maar door alle conspirancy theorieën voor zoete koek te slikken verspeelt zo'n artikel wel credit bij mij.

quote:

Op zondag 5 juni 2005 12:02 schreef UncleScorp het volgende:

[..]

Mja, zelfde geldt voor de officiële uitleg waar ook heel wat gaten in zitten ... draagt ook niet echt bij tot de geloofwaardigheid ...

quote:

Op zondag 5 juni 2005 14:41 schreef TopGear het volgende:
WTC 7 is opgeblazen.
Dat is toegegeven door de eigenaar Larry Silverstein.

Opblazen vergt weken van voorbereiding..... dus de hele zooi is gepland.
NORAD die niet ingrijpt.
Terroristen die weer levend opduiken.
Nep Telefoontjes uit vliegtuigen.
Vliegtuig zou zijn neer gestort..... bleek te zijn neergeschoten.....
Zoveel mensen die van tevoren gewaarschuwd zijn voor 9/11.......

Enz............

quote:

I remember getting a call from the, er, fire department commander, telling me that they were not sure they were gonna be able to contain the fire, and I said, 'We've had such terrible loss of life, maybe the smartest thing to do is pull it.' And they made that decision to pull and we watched the building collapse

quote:

Op zondag 5 juni 2005 14:55 schreef Wombcat het volgende:

[..]

Dat opgeblazen verhaal, dat komt uit zijn volgende quote:
[..]

In brandweertermen betekent "Pull it" het gebouw opgeven, niet opblazen.

quote:

Op zondag 5 juni 2005 16:59 schreef TopGear het volgende:

[..]

Het slimste is om het gebouw op te geven.
Zij maakten de beslissing om het op te geven en toen zagen we het gebouw instorten.

Geloof jij het?

quote:

Op zondag 5 juni 2005 16:59 schreef TopGear het volgende:

[..]

Het slimste is om het gebouw op te geven.
Zij maakten de beslissing om het op te geven en toen zagen we het gebouw instorten.

Geloof jij het?

quote:

After WTC 2 collapsed:
* Some south face glass broken at lower floors
* dust covered lobby areas at floors 1 and 3
* power on in building, phones working
* no fires observed

quote:

After WTC 1 collapsed:
* heavy debris on VEsey street and WTC 7 promenade
* no heavy debris observed in lobby area, white dust coating
* SW corner damage - floors 8 to 18
* south face damage between two exterior colums -roof level down 5 to 10 floors - extent not known
* south face damage:
* middle 1/4-1/3 width south face - 10th floor to ground
* large debris hole near centre around 14th floor
* 1/4 width south face, above 5th floor, atrium glass intact
* 8th/9th floor from inside, visible south wall gone with more damage to west, 2 elevator cars dislodged into elevator lobby

quote:

Observer fire locations:
General
* no diesel smells reported from the exterior, stairwells or lobby
* no signs of fire or smoke below floor 6 from stairwell and lobby areas
* fire reported at west wall of floor 7 around 12:15 pm
* in east stairwell, smoke was observed near floors 19-20, signs of a fire observed on floor 23
looking from SW corner to south face
* Fire in SW corner near floor 10 or 11
* fire on floors 6, 7, 8, 21, 30
* multiple fires observerd on floors 20s and 30s
* heavy black smoke coming out of south face gash, no fire observed
Looking form SE corner to south face
* fire on floor 12¹, area above covered with smoke
* fire on floors 11-12¹, moved to east face and progressed to north

¹fires reported on floor 14, but photographs show east face fires on floor 12

quote:

Failure sequence timeline
(sec)
0.0 Movement of east penthouse roofline
0.9 East penthouse kinks between columns 44 and 45; 2 windows at floor 40 fail between colums 44-45
1.2 4 windows fail at floor 40; east penthouse submerged from view (now inside buidling)
1.7 3 windows break at floors 41 to 44
4.0 windows break along column 46 at floors 37 and 40
7.0 north side of west penthouse moves; movement of entire north face of WTC7 (visible above floor 21)
7.2 west end of roof starts to move
7.7 east end of roof starts to move; facade kink formed along columd 46-47
7.9 west penthouse submerged
8.2 global collapse occurs as windows fail between floors 33-39 around column 55

quote:

A working collapse hypothesis has been developed with four phases:
* an initiating event
* vertical progression on the east side
* horizontal progression from east to west
* global collapse

initiating event
first exterior sign of failure was at the east penthouse rooflinen, alignes with interior columns 79, 80 and 81. Postulated events include the failure of these colums.

vertical progressions
Colums 79, 80 and 81 supported large tributary areas for floors spans of app. 50 ft. Failure of column 79, 80 and 81 would likely result in failure at the floor-column connections and would progress vertically up to the east penthous.

horizontal progression
* a vertical failure would pile debris on the east side of the building, damaging or severing transfer girders and trusses between floors 5 and 7
* this secondary damage has been postulated to cause a horizontal progressoion of failure in the core columns at or near floors 5 and 7.

global collapse
the global collapse ocured with few external signs and is postulated to have occured with the failure of core colums

quote:

status
* a working hypothesis had been developed
* the hypothesis is consisten with visual observations