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Re: Questions About the Events of September 11th (off topic)

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Don't you think that your no. 2 item was caused to a great degree by the
now known gross inadequacy of the type of spray-on fire retardant
treatment which was used on the steel?

Stan Scholl, P.E.
Laguna Beach, CA

On Mon, 11 Nov 2002 14:36:37 -0600 "Sprague, Harold O."
<SpragueHO(--nospam--at)bv.com> writes:
> Read the FEMA 403.  
> http://www.house.gov/science/hot/wtc/wtcreport.htm and
> Ron Hamburger's "Structural Performance of the World Trade Center 
> and
> Surrounding Buildings on September 11, 2001".
> 
> You will find that indeed the 707 is not that much different than 
> the 767
> (see FEMA 403, Fig. 1-10), but the analysis technology to do impact 
> analysis
> was greatly limited in the 1960's when the design and analysis for 
> the WTC
> was done.  Local impact nonlinear effects were almost impossible to 
> do back
> then.  This was a time of slide rules and giant main frame computers 
> with
> less power than what you now carry in a brief case.  
> 
> What the engineers did was to look at the impact energy on the 
> structure as
> a whole, and wind dominated.  The 707 was perceived to be an 
> aircraft at
> landing speed lost in fog (similar to the B-25 that hit the Empire 
> State
> Building).  The high velocity of the 767 and fuel fire ignition over 
> a large
> floor plate were not design considerations.
> 
> The plane fuel load was the source of multiple fire ignitions, and 
> the fuel
> / air explosion, and impact removed a lot of fireproofing from the 
> trusses.
> The fuel itself flashed off in about 6 to 8 minutes.  From that 
> point on,
> office furnishings were the source of the fire.  The fire was NOT 
> hot enough
> to melt the steel, but it was hot enough to significantly reduce the 
> steel
> strength for the unprotected steel trusses.  
> 
> Ultimately the collapse of WTC 1 and WTC 2 was due to:
> 1.	A severely damaged structural system directly due to the 
> plane
> impact 
> 2.	Yield strength degradation due to fire at multiple 
> locations in the
> structure.
> 
> I have seen many collapses including telecommunication towers with 
> all of
> the guys on one side cut.  Even with that, the tower leaned over 
> some before
> it spiraled down on the base.  It does not fall over like a felled 
> tree.  
> 
> Yes, I have been to the site.  There was no conspiracy other than 
> with the
> terrorists, there was no "gasoline", and no steel "melted".  There 
> were no
> construction corners cut.  There were no errors in the design or 
> design
> assumptions.  Aside from the terrorists, there were only issues of 
> material
> science, the ignition effects of Jet A fuel, and basic laws of 
> physics that
> caused one of the worst tragedies we have ever witnessed.  
> 
> Are there lessons to be learned?  Yes, but the issues you have 
> raised are
> not germane.  Whether or not your questions are "reasonable" or not 
> will
> only be determined AFTER you have done real research.  The research 
> starts
> with reading the FEMA 403.  There has been recent analysis that 
> corroborates
> the scenario of events.  Watching TV reports is not a good source of
> research.  
> 
> Run your ANSYS and NASTRAN nonlinear dynamic modeling to predict the
> airliner impact damage, then select truss members and start dropping 
> the
> yield strength to initiate the collapse mode.  Then your model will 
> go to a
> dynamic impact model.  
> 
> Regards,
> Harold O. Sprague
> 
> > -----Original Message-----
> > From: Min Young Park [mailto:pmy1970(--nospam--at)yahoo.ca] 
> > Sent: Monday, November 11, 2002 10:16 AM
> > To: seaint(--nospam--at)seaint.org
> > Subject: Re: Questions About the Events of September 11th (off 
> topic)
> > 
> > I think you get me wrong.
> > I don't buy what they say. It's too much to take.
> > What I am interested in is how the building collapsed
> > structually. That's why I put this issue on this
> > board.
> > Did you really visit the site and read what they say?
> > After 911, I have been asked about how the building
> > collapsed in that manner.
> > But whenever I tried to answer the question, I came
> > short. I believe the 'melt-down by airplane fuel'
> > theory is a popular answer for that question. But it
> > doesn't make any sense to me. 
> > 
> > Do you think the gasolin ran down to the bottom and
> > melt whole columns in that short period of time? As
> > you can see in many pictures, there was fire only in
> > local area not in whole building. To achieve the
> > building collapse in that manner, the columns should
> > be melt evenly otherwise some columns fail first then
> > part of the building will tip over into other
> > buildings.
> > 
> > After 911, I saw an interview on TV. A civil engineer
> > who was involved in the construction of WTC said the
> > building had been designed for Boeing 707. But I've
> > heard that Boeing 767, which is the one hit the WTC,
> > has simillar weight, size and speed. So, if the
> > building had been designed for Boeing 707, it should
> > have been Ok with Boeing 767 also. As you know,
> > strcutural engineers allow some severe demage for that
> > kind of large load but not the collapse. If it
> > collapsed only by the airplane, the engineer can not
> > avoid the blame.
> > 
> > As you may know, the WTC has shear walls in the middle
> > of the building continuous from the bottom to the top.
> > These walls are mainly for lateral loads.(Of course
> > they also take some vertical loads) And some of the
> > walls take only a little of vertical loads. If we take
> > this shear wall as a cantilever beam, how come this
> > collapse in that manner under the lateral load at the
> > tip? 
> > 
> > Let's suppose we have a 100 storey higerise building
> > to be demolished in the middle of other buildings. It
> > must not tip over into other buildings during the
> > demolition. It would be perfect if it collapse in the
> > same manner shown in WTC collapse.
> > How much money & time do you think you have to spend
> > on the engineering to achieve this kind of perfect
> > demolition?
> > What is the possibility of getting this kind of
> > perfection with a random load? not just once but
> > twice. I would say "mission impossible".
> > 
> > Whenever people hear "WTC fake collapse", their
> > response is " shut up you moron" even though they are
> > approching with reasonable questions. As a structural
> > engineer you can not say like them because you are the
> > one who is supposed to answer with reasonable theory.
> > As I said I don't believe this fake story. I am just
> > looking for more reasonable answer by engineer.
> > 
> >  --- richard lewis <rlewistx(--nospam--at)juno.com> wrote: > This
> > email message reminds me how blessed we are to
> > > live in a free
> > > society.  We take so much for granted.  I can only
> > > assume Mr. Ming has
> > > grown up in a society where he must distrust
> > > everything the government
> > > does and must be constantly looking over his
> > > shoulder.  It is sad that
> > > all over the world human nature can do the evil
> > > atrocities that he
> > > insinuates here.  I am so glad we are blessed with
> > > our free society that
> > > makes it almost impossible for the scenario that he
> > > suggests to happen.
> > > 
> > > Lets look at this logically.  If Mr. Ming is correct
> > > in his assertions
> > > there would have to be hundreds of people who would
> > > know the truth and
> > > not speak up.  Our free press allows anyone who
> > > knows something to go
> > > public with it, even anonymously.  How could the
> > > government hide all this
> > > information from the press.  I think that would be
> > > impossible.  Just ask
> > > Richard Nixon.  Sooner or later someone will speak. 
> > > Do you really think
> > > an airforce pilot and all his support staff could
> > > keep it secret that he
> > > took off with a load of missiles and landed with at
> > > least one less on the
> > > day of the plane crashed near Pittsburg and NOBODY
> > > let it slip to the
> > > press?  Do you really think a similar situation
> > > could happen with a
> > > similar air force jet that was flying near the
> > > Pentagon?  Do you really
> > > think that a team of construction demolition people
> > > could rig a building
> > > for collapse and NOBODY on the team would mention it
> > > after it happens? 
> > > Do you really think a 767 jet with passengers never
> > > flown into the tower,
> > > but some other military weapon was used, and the
> > > government is still
> > > hiding the passengers or has killed them secretly
> > > somewhere else?  Do you
> > > really think that the dust at the WTC was something
> > > else other than
> > > concrete and fire proofing?  Do you really think it
> > > was planned for one
> > > tower to fall before the other?  Do you really think
> > > you would find human
> > > remains of a collision accident of several hundred
> > > miles per hour
> > > combined with an explosion?
> > > 
> > > Now if I was living in Iraq, Pakistan or one of many
> > > other dictator
> > > countries around the world I would think the
> > > scenario of Mr. Ming would
> > > be plausible.  But just ask the Russians, how long
> > > can you keep a secret
> > > from the public?  Sooner or later someone creditable
> > > talks.  We have not
> > > seen that yet, just Mr. Ming
> > > 
> > > Again, we are so blessed with are freedom, the envy
> > > of the world!  God
> > > bless America!
> > > 
> > > 
> > > Rich
> > > 
> > > On Sat, 9 Nov 2002 09:48:37 -0500 (EST) Min Young
> > > Park <pmy1970(--nospam--at)yahoo.ca>
> > > writes:
> > > > As a structural engineer, have you ever wondered
> > > how
> > > > the World Trade Center collaped by the airplanes?
> > > 
> > 
> 
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