Update:
Structure
Magazine, a well respected magazine for structural
engineers, has come out with a probable collapse hypothesis.
"Single Point of Failure: How the Loss of One Column May
Have Led to the Collapse of WTC 7" points out that the
failure of column 79 in the lower levels will create the
very effect we see in videos.
http://www.structuremag.org/Archives/2007-11/SF-WTC7-Gilsanz-Nov07.pdf
Yet another peer
reviewed paper from a respected Journal finds the towers
were doomed to collapse.
9/11 demolition theory challenged
An
analysis of the World Trade Center collapse has
challenged a conspiracy theory surrounding the 9/11
attacks.
The study by a Cambridge University, UK, engineer
demonstrates that once the collapse of the twin towers
began, it was destined to be rapid and total.
One of many conspiracy theories proposes that the
buildings came down in a manner consistent with a
"controlled demolition".
The new data shows this is not needed to explain the
way the towers fell.
Resistance to collapse
Dr Keith Seffen set out to test mathematically
whether this chain reaction really could explain what
happened in Lower Manhattan six years ago. The findings
are published in the Journal of Engineering Mechanics.
Previous studies have tended to focus on the initial
stages of collapse, showing that there was an initial,
localized failure around the aircraft impact zones, and
that this probably led to the progressive collapse of
both structures.
In other words, the damaged parts of the tower were
bound to fall down, but it was not clear why the
undamaged building should have offered little resistance
to these falling parts.
"The initiation part has been quantified by many
people; but no one had put numbers on the progressive
collapse," Dr Seffen told the BBC News website.
Dr Seffen was able to calculate the "residual
capacity" of the undamaged building: that is, simply
speaking, the ability of the undamaged structure to
resist or comply with collapse.
His calculations suggest the residual capacity of the
north and south towers was limited, and that once the
collapse was set in motion, it would take only nine
seconds for the building to go down.
This is just a little longer than a free-falling
coin, dropped from the top of either tower, would take
to reach the ground.
He added that his calculations showed this was a
"very ordinary thing to happen" and that no other
intervention, such as explosive charges laid inside the
building, was needed to explain the behavior of the
buildings.
The controlled detonation idea, espoused on several
internet websites, asserts that the manner of collapse
is consistent with synchronized rows of explosives going
off inside the World Trade Center.
This would have generated a demolition wave that
explained the speed, uniformity and similarity between
the collapses of both towers.
Conspiracy theorists assert that these explosive
"squibs" can actually be seen going off in photos and
video footage of the collapse. These appear as ejections
of gas and debris from the sides of the building, well
below the descending rubble.
Other observers say this could be
explained by debris falling down lift shafts and
impacting on lower floors during the collapse.
http://news.bbc.co.uk/2/hi/science/nature/6987965.stm
Dr. Keith A. Seffen
http://www.eng.cam.ac.uk/~kas14/
Below is the list of people
who have staked their reputations on the only paper which passed the
scrutiny of peer review regarding the WTC tragedy...
For those who may think
that no
one has written a peer reviewed paper on the collapse of the towers here
it is...
"Walter P. Murphy
Professor of
Civil Engineering and
Materials Science
Northwestern
University
The towers of the World
Trade Center were designed to withstand as a whole the horizontal impact
of a large commercial aircraft. So why did a total collapse occur? The
reason is the dynamic consequence of the prolonged heating of the steel
columns to very high temperature. The heating caused creep buckling of
the columns of the framed tube along the perimeter of the structure,
which transmits the vertical load to the ground. The likely scenario of
failure may be explained as follows...
http://www-math.mit.edu/~bazant/WTC/WTC-asce.pdf
The version linked above,
to appear in the Journal of Engineering Mechanics (ASCE), was revised
and extended (with Yong Zhou on September 22 and additional appendices
on September 28) since the original text of September 13, which was
immediately posted at various civil engineering web sites, e.g.
University of Illinios. It also has been or soon will be published in a
number of other journals, including Archives of Applied Mechanics, Studi
i Ricerche, and SIAM News:
Z. P. Bazant and Y. Zhou,
"Why Did the World Trade Center Collapse?", Society for Industrial and
Applied Mathematics News, vol. 34, No. 8 (October, 2001).
That means it's not just a
document, book, web site or calculation on a forum. It's had to pass
critical review by other engineering Professors.
I know there are CT sites which attack this paper but not
one person has yet to disprove its hypothesis
professionally. There are still people attacking the theory
of evolution. Anyone can attack, not many can produce a
paper to back it up. Just as there is no "theory of
intelligent design" except on Christian web sites, there are
no alternatives to this paper other than in CT sites and
books."
http://www-math.mit.edu/~bazant/WTC/
The paper...
http://www-math.mit.edu/~bazant/WTC/WTC-asce.pdf
http://www.pubs.asce.org/journals/edem.html
Editor:
Ross B. Corotis, Ph.D.,
P.E., S.E., NAE, University of Colorado, Boulder
corotis@colorado.edu
http://ceae.colorado.edu/new/faculty/people/people.cgi?corotis
Editorial Board:
Younane Abousleiman,
Ph.D., University of Oklahoma
http://mpge.ou.edu/faculty_staff/faculty.html
Ching S. Chang, Ph.D.,
P.E., University of Massachusetts
http://www.ecs.umass.edu/cee/faculty/chang.html
Joel P. Conte, Ph.D.,
P.E., University of California, San Diego
http://kudu.ucsd.edu/
Henri Gavin, Duke
University
http://www.cee.duke.edu/faculty/gavin/index.php
Bojan B. Guzina,
University of Minnesota
http://www.ce.umn.edu/people/faculty/guzina/
Christian Hellmich,
Dr.Tech., Vienna University of Technology
http://whitepages.tuwien.ac.at/oid/998877.html
Lambros Katafygiotis,
Ph.D., Hong Kong University of Science and Technology
http://lambros.ce.ust.hk/
Nik Katopodes, Ph.D.,
University of Michigan
http://www.engin.umich.edu/dept/cee/prospective/
Nicos Makris, University
of Patras
http://www.civil.upatras.gr/Melidep_gr/depi_en.asp?profid=5
Robert J. Martinuzzi,
P.E., University of Calgary
http://www.ucalgary.ca/pubs/calendar/2005/who/stafflists/academicAlpha.htm
Arif Masud, Ph.D.,
University of Illinois, Chicago
http://www.uic.edu/depts/bioe/faculty/core_faculty_list.htm
Arvid Naess, Ph.D.,
Norwegian University of Science and Technology
http://www.bygg.ntnu.no/~arvidn/front.htm
Khaled W. Shahwan, Daimler
Chrysler Corporation
http://www.pubs.asce.org/WWWdisplay.cgi?9800592
George Voyiadjis, Ph.D.,
EIT, Louisiana State University
http://www.cee.lsu.edu/facultyStaff/Voyiadjis_George/Voyiadjis_Gbio.htm
Yunping Xi, Ph.D.,
University of Colorado
http://ceae.colorado.edu/new/faculty/people/people.cgi?xi
Engineering
Mechanics Division Executive Committee
Alexander D. Cheng, Ph.D.,
M.ASCE, Chair
http://home.olemiss.edu/~acheng/
James L. Beck, Ph.D.,
M.ASCE
http://www.its.caltech.edu/~jimbeck/
Roger G. Ghanem, Ph.D.,
M.ASCE
http://ame-www.usc.edu/personnel/ghanem/index.shtml
Wilfred D. Iwan,
M.ASCE
http://www.eas.caltech.edu/fac_i-m.html#i
Chiang C. Mei,
M.ASCE
http://cee.mit.edu/index.pl?id=2354&isa=Category&op=show
Verna L. Jameson, ASCE
Staff Contact
Journal of Engineering Mechanics
Bazant, Z.P., & Zhou, Y.
"Addendum
to 'Why Did the World Trade Center Collapse? - Simple Analysis"
(pdf)
Journal of Engineering
Mechanics v. 128, no. 3, (2002): 369-370.
Brannigan, F.L.
"WTC:
Lightweight Steel and High-Rise Buildings"
Fire Engineering v.155, no. 4, (2002):
145-150.
Clifton, Charles G.
Elaboration
on Aspects of the Postulated Collapse of the World Trade Centre Twin
Towers
HERA:
Innovation in Metals. 2001. 13 December 2001.
"Construction
and Collapse Factors"
Fire
Engineering v.155, no. 10, (2002): 106-108.
Corbett, G.P.
"Learning
and Applying the Lessons of the WTC Disaster"
Fire Engineering v.155, no. 10, (2002.):
133-135.
"Dissecting
the Collapses"
Civil
Engineering ASCE v. 72, no. 5, (2002): 36-46.
Eagar, T.W., & Musso, C.
"Why
Did the World Trade Center Collapse? Science, Engineering, and
Speculation"
JOM v. 53,
no. 12, (2001): 8-12.
Federal Emergency Management Agency, Therese
McAllister, report editor.
World
Trade Center Building Performance Study: Data Collection, Preliminary
Observations, and Recommendations
(also
available on-line)
Gabrielson, T.B., Poese, M.E., & Atchley,
A.A.
"Acoustic
and Vibration Background Noise in the Collapsed Structure of the World
Trade Center"
The Journal
of Acoustical Society of America v. 113, no. 1, (2003):
45-48.
"Collapse
Lessons"
Fire
Engineering v. 155, no. 10, (2002): 97-103
Marechaux, T.G.
"TMS
Hot Topic Symposium Examines WTC Collapse and Building
Engineering"
JOM, v.
54, no. 4, (2002): 13-17.
Monahan, B.
"World
Trade Center Collapse-Civil Engineering Considerations"
Practice Periodical on Structural Design
and Construction v. 7, no. 3, (2002): 134-135.
Newland, D.E., & Cebon, D.
"Could
the World Trade Center Have Been Modified to Prevent Its
Collapse?"
Journal of
Engineering Mechanics v. 128, no. 7, (2002):795-800.
National Instititue of Stamdards and
Technology: Congressional and Legislative Affairs
“Learning from 9/11:
Understanding the Collapse of the World Trade Center”
Statement of Dr. Arden L.
Bement, Jr., before Committee of Science House of Representatives, United
States Congress on March 6, 2002.
Pinsker, Lisa, M.
"Applying Geology
at the World Trade Center Site"
Geotimes v. 46, no. 11, (2001).
The print copy has 3-D images.
Public Broadcasting Station (PBS)
Why the Towers Fell:
A Companion Website to the Television
Documentary.
NOVA (Science Programming
On Air and Online)
Post, N.M.
"No
Code Changes Recommended in World Trade Center Report"
ENR v.
248, no. 14, (2002): 14.
Post, N.M.
"Study
Absolves Twin Tower Trusses, Fireproofing"
ENR v. 249, no. 19,
(2002): 12-14.
The University of Sydney, Department of Civil
Engineering
World Trade Center -
Some Engineering Aspects
A
resource site.
"WTC
Engineers Credit Design in Saving Thousands of Lives"
ENR v.
247, no. 16, (2001): 12.
