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Conspiracy Theories, 9/11 and the Twin Towers (and WTC7) collapses

Alasdair N. Beal BSc Hons I CEng FICE FIStructE, Leeds, UK  anbeal@btinternet.com

From time to time I have written to websites and groups interested in 911 providing answers to some of their ‘unanswered questions’ and pointing out that some of the theories and propositions they are repeating were proved wrong long ago. They rarely respond. Many of those involved seem to have come to the subject with their minds already made up and are not interested in genuinely open investigation.

I am a chartered civil and structural engineer and have investigated many building failures, including collapses, fire damage etc. I am also familiar with demolition techniques and have met the people who do controlled demolition, I know how they do it and I have seen (and filmed) it being done on a real building.

I learned long ago when investigating structural problems in buildings that initial assumptions about what has happened are sometimes correct but other times they are way off-beam; the only way to find the truth is to keep an open mind and follow the evidence. The other thing I learned is that although complicated, obscure and unprovable explanations can be fun, the true explanation is usually simple and mundane, although sometimes hard to find. In the end the truth is what it is, not what we want it to be.

When I first watched the twin towers collapses live on television I thought “Oooh, that looks suspiciously like controlled demolition” and I maintained that suspicion for some time. However many people do not understand that in controlled demolition the key is the pre-weakening of the structure, so that it takes only small explosive charges to make it collapse - it is gravity which does all the hard work. They also forget that fire can be used instead of explosives to achieve the same result, as Fred Dibnah’s chimney demolition films demonstrate vividly.

I only discounted the idea of ‘controlled demolition by explosives’ in the Twin Towers after watching many TV programmes and looking at many websites. I realised that even if the official enquiries have not answered all the questions it is pretty clear that the damage caused to structure and fire protection by the aeroplane impacts, the fires which followed and possible explosions as water came into contact with hot molten aluminium could have done sufficient damage by themselves to explain the collapses. It was also obvious that although the alternative theorists have a lot of good questions, ‘unexplained facts’ and rhetoric, their alternative explanations are complex and obscure (always a bad sign), with very little specific supporting evidence (another bad sign).

It has been claimed that there are ‘2,600 structural engineers and high-rise architects who comprise Architects & Engineers for 9/11 truth’. However if you check their website, it only says that 2640 architects and engineers have signed their petition. Many of these engineers are not structural engineers and many of the architects have never designed high rise blocks. ‘911 Truth’ campaigners ask some good questions - but they carry on asking some of them long after they have been answered and hang on to theories for which there is no evidence. They also make assertions that are nonsense.

For example, it is often claimed that there are no known cases of a steel framed building collapsing because of fire but this is simply not true - I have seen and investigated several myself. It is also often suggested that for collapse to occur the steel must be hot enough to melt - again nonsense: it only needs to be hot enough (typically about 550º C) to reduce its strength to 50-60% of its ‘cold’ strength, removing the safety margin against failure and then gravity does the rest. The World Trade Center buildings had lightweight floors supported on steel trusses, which are very vulnerable to connection or bracing failure in a fire. The towers had heavy steel main columns - but the stability of these depended on the floors and light bracing members, so even if the column steel was still full strength, failure of the bracing members or floor beams or their connections could easily trigger column buckling failure.

Some theorists have noticed that when the structures failed the main steel columns fell at virtually free-fall speed and claim that this is some kind of mystery. However this is exactly what a long heavy column will do under the influence of gravity if it loses its support - regardless of whether that support is removed by explosion, fire, vandalism or aliens. If you look carefully at videos of the collapses, in the midst of the flames, dust, noise etc. you will catch glimpses of long main columns falling vertically towards the ground - in free fall, driven by gravity. It’s not a mystery - it’s simple, basic physics.

The ‘controlled demolition by explosives’ theorists have produced remarkably little hard evidence: they simply assert that the failures look like controlled demolition by explosives so this must be what happened. One theorist claims that the explosive used was thermite, claiming as evidence the fact that red hot steel was still being removed from the wreckage days after the collapses. However how would thermite keep the steel red hot for days? The steel temperature several days after the collapse has nothing to do with its temperature at the time of the collapse - the heat must have come from the fires which burned afterwards. Also, if thermite was the obvious demolition agent, why is it not used by real controlled demolition engineers?

Consider the ‘controlled demolition by explosives’ theory in more detail. Controlled demolition of a building is not done by stacking explosives in the basement and blowing it up. Many other things must be done first: (i) non-structural partitions etc. that might carry load are removed, then (ii) key members such as main columns are partly cut through to weaken them and then (iii) explosive cutting charges are attached to the columns and linked up by cables so that when they explode they will cut and break up the structure in a sequence which is precisely-timed in three dimensions so that it will fall to the ground in the intended way. That is why it is called ‘controlled demolition’.

Preparing a building the size of one of the World Trade Center towers for controlled demolition would take weeks of widespread intrusive work in many areas, with men cutting its main columns at numerous locations, fixing explosives and wiring it all up. Strangely, none of the survivors has mentioned seeing any such activity in the weeks before the collapse and none of the people escaping from the buildings seem to have noticed that they were all rigged up with cables and explosives.

The twin towers (and also WT7) had floors of lightweight construction, with floor trusses spanned between central core columns and facade columns and supported by ‘dead bearing’ connections which could support large downward loads but had only a small capacity for loads in the reverse direction. Also the strength of the trusses relied on them acting compositely with the lightweight concrete floors, but these would have disintegrated under reverse loading. A failure fairly low down in the central core would lead to the central core columns and the floors falling vertically, with the floors and floor beam connections disintegrating under the reversed loading and the surrounding facade acting as a 'guide tube' to keep things roughly upright as they fell. This is exactly what you see happening in the videos.

This explanation is simple and relies only on what we actually know. Why there was a rush to remove steel from the sites, why were forensic investigations limited, why did George W Bush do nothing, why weren’t interceptor planes scrambled etc. etc. ? I don’t know but this doesn’t change the fact that the Twin Towers were hit by large aeroplanes and then suffered major fires - and this is probably why they collapsed.

The alternative theorists would ask us to believe that the fires and aeroplane impacts were essentially irrelevant and the real reason the buildings collapsed was that in the preceding weeks groups of people entered the buildings, cut and weakened the main structural columns, rigged them with thermite explosive charges and then set these charges off in a carefully-controlled sequence after the aeroplanes had crashed into the buildings and set them on fire. Of course this is not completely impossible and it is possible that a conspiracy to suppress the truth has concealed the evidence ... but it is also possible that evidence to support the theory cannot be found simply because it never happened.

It is true that the details of the World Trade Center 7 collapse are less well understood than the Twin Towers. (Details of the attack and damage to the Pentagon are also limited but that's hardly a surprise.) However the fires within WT7 burned for a long time and they were not ‘small’.

Also anyone proposing a theory of ‘controlled demolition demolition by explosives’ for WT7 should first consider the list of WT7 tenants: Salomon Smith Barney (bankers), ITT Hartford Insurance Group, American Express Bank International, Standard Chartered Bank, the Securities and Exchange Commission, the Internal Revenue Service Regional Council, the United States Secret Service, the New York City Office of Emergency Management, the National Association of Insurance Commissioners, Federal Home Loan Bank, First State Management Group Inc., Provident Financial Management, the Immigration and Naturalization Service, the Department of Defense (DOD) and Central Intelligence Agency (CIA).

Would it make sense for government spooks to blow that lot up? Is it believable that a team of controlled demolition engineers could enter the offices of all these organisations, cut and weaken the main structural columns, place explosive charges and wire them up ... and do all this without a single one of these high-security tenants noticing? Of course perhaps they said nothing because they were also in on the conspiracy - but if they were, why didn’t they at least remove their files and warn their staff to go home before the building was blown up? If this really happened, isn't it extraordinary that many years later not one of the hundreds or thousands of people that would have had to be involved has ever breathed a word about it to anyone?

The biggest obstacle to these theories is our old friend Occam’s Razor: it is a mistake to make a theory more complicated than necessary and the simplest explanation which fits the observed facts is the most likely to be true. We know without any doubt that a large aluminium jetliner collided with each of the Twin Towers, causing a lot of damage and starting large fires. Despite what people may say or want to believe, it is a fact that the combined effects of these could have caused the buildings to collapse. Thus there is a possible, rational explanation for the collapses which relies only on what we actually know. Other theories and explanations are possible but they are not necessary.

Sometimes I try to imagine the scene at the headquarters of Al Quaeda/ Mossad/ the CIA/ the Neasden Liberation Front or whoever it was that actually planned it all. A special meeting has been convened to hear a presentation by Commandante Zero outlining his brilliant and exceptionally cunning plan for an attack on the Twin Towers:

“First of all we recruit people willing to participate in a suicide mission and get them trained as airliner pilots, then we then we recruit some more people to go with them and get them all booked on flights at appropriate times. They then smuggle weapons through security, board the arranged flights, storm the airliner cockpits, take over control and crash them into the Twin Towers, the Pentagon and (possibly) the White House. The collisions should cause huge damage to the buildings, set them on fire and possibly cause them to collapse.”

The meeting starts to applaud but Commandante Zero interrupts -

“Hold on, that’s only half of the plan. As well as doing all this, in the weeks before the attack we should also recruit three teams of controlled demolition experts and get them to secretly enter WTC1 WTC2 and WTC7, cut part way through all of their main supporting columns and wire them up with explosives without anybody noticing. Then after the planes have crashed and set fire to the buildings we can demolish the buildings by controlled demolition. Nobody has ever carried out controlled demolition of a burning building before, so this would really put our name on the map. Oh ... and also instead of using the usual explosives for controlled demolition we should use this stuff called thermite which I have read about on the internet. Oh ... and obviously we shall have to do all this in conditions of total secrecy, without anyone involved breathing a word about it, before, during or afterwards. Now, tell me, what do you think of my plan .... ?”

Sorry to be a bit of a spoilsport but would any self-respecting terrorist organisation (or nasty government agency) even consider making the plan so complicated, when crashing planes into the buildings would be quite enough to shock America to the core? Adding controlled demolition to the plan adds cost, complexity and difficulty and greatly increases the risk of discovery but it adds nothing to the likely propaganda impact. What would be the point?

I simply don't believe it.

We live in a wicked world and there are certainly conspiracies. 911 is interesting: for once, everyone agrees that there definitely was a conspiracy - there are no ‘non-conspiracy’ theories. There are many important questions to be answered about 9/11 and its aftermath, including who was really behind what happened, who knew in advance or turned a blind eye, what aspects were simply incompetence and what all of this had to do with Afghanistan and Iraq. Even more importantly, we should be asking what we should do now to make good the damage done to these countries (and others) in the name of 9/11 and what we should do to obtain justice and peace for Palestine and end the Israel/Palestine conflict, which always seems to lurk somewhere in the background.

For more detailed discussions the website www.debunking911.com is useful. It includes a lot of the evidence which is ignored or edited out of self-styled '911 Truth' websites and videos.

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