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Op een overzichtspagina van Penn State staan berichten van de ramp. Uitgangspunt is het instorten van de torens door vuur. Zie deze Google zoeklink voor een overzicht van alle pagina's uit die folder.

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Onderstaand volgt een overzicht van de pagina. Links en tekst die verwijzen naar donaties e.d. zijn van die pagina verwijderd. Dit overzicht is gemaakt op woensdag 24 mei 2006. Het kan dat de originele pagina inmiddels is bijgewerkt. De pagina staat hier voor archief.

This site has grown significantly beyond any of my expectations. My initial intent was to provide a source of information for the Penn State AE community. Over the months since September 11, 2001 I have found that many people have found it useful. I will continue to update the site as new information is located. Please send any information you have to Prof. Louis Geschwindner at lfg@psu.edu.

102 Minutes - Inside the Twin Towers - From their last words, a haunting chronicle of the last 102 minutes at the World Trade Center

Observances marking 9/11 Anniversary

NIST Investigation

FEMA/ASCE Building Response Team Report

  • 04/08/02 The New York Times comments on the FEMA/ASCE Team report that they obtained. Their conclusions are not necessarily an accurate interpretation of what the report actually says.
  • 04/08/02 The New York Times in an article "U.S. Report on Trade Center Echoes Lessons of Past Disasters," again draws conclusions that are not necessarily consistent with the facts of building response to fire. The April 8, 2002 issue of ENR contains a well written editorial "Office Towers Are Safest Buildings of Them All" critique of the NYT article and should be read by all who are interested in the assessment of building response to fire.
  • 07/24/02 Letter to the editor discussing above editorial.
  • 04/17/02 ENR reports on the Building Response Team (FEMA/ASCE) presentations at the ASCE Structures Congress pointing out that the final report will recommend no code changes.
  • 04/30/02 NOVA will air a program April 30, based on the FEMA/ASCE investigation.
  • 04/30/02 The designers of the World Trade Center did not sacrifice safety to save money and should not be blamed for the loss of more than 2,800 lives in the collapse of the 110-story twin towers. "It's my opinion that they did not skimp at all," said the engineer, W. Gene Corley who heads the FEMA/ASCE team.
  • 05/15/02 NYT Discussion of the FEMA/ASCE report prior to its release (May 1)
  • 05/03/02 The final report of the FEMA/ASCE Building Performance Study Team has been released. It is found on the web page of the House Committee on Science, in *.pdf format.
  • 05/15/02 William Faschan, of Leslie E. Roberston Associates discusses the process of designing skyscrapers by requiring anticipation of the unknown.
  • 05/15/02 Reuters reports on the FEMA/ASCE and how it is virtually impossible to make buildings strong enough to withstand the massive damage that brought down the World Trade Center towers.
  • 05/15/02 The Washington Post reports on the FEMA/ASCE report.
  • 05/15/02 A review of the NOVA TV presentation.
  • 05/15/02 ASCE News release on the FEMA/ASCE report.
  • 05/15/02 The Financial Times reports on the release of the FEMA/ASCE report.
  • 05/15/02 It is encouraging at just how well pointed Nadine Post and her colleagues at ENR are in getting to the heart of the issues from FEMA/ASCE WTC report. This is an outstanding article by folks who know engineering.
  • 05/16/02 The Structural Engineers of California listserv has discussed issues generated by the NOVA program. Three specific questions and comments may be of interest. Message 794, message 874, and message 924.
  • 06/09/04 A series of articles in Plumbing Engineer assesses the FEMA report, the NIST investigation and the push to modify building codes. A must read for anyone interested in a reasoned review of where we are headed. The combined series is available here.
  • 06/09/04 ENR has once again stepped up and presented a hard hitting report on the fear mongers centering heri efforts on teh WTC in a cover story: FIRE PROTECTION: Skyscrapers' Supporters Infuriated By Fire Fearmongers. Antagonists, feeding on post-9/11 jitters, magnify danger of towering infernos (6/7/2004 Issue) By Nadine M. Post. This link will take you to the first of a 5 page article.The articles by Richard Schulte that are referred to here are linked directly above.

Six Plans for Ground Zero (And More)

Building Code Revisions

Analysis of Collapse

  • 11/01/01 An ENR article that should have been linked from the first days. Massive Assault Doomed Towers Terrorist Attacks Brings Down World Trade Center (9/17/2001).
  • 09/20/01 USA Today has an excellent graphic describing the structure and the collapse of the WTC Towers.
  • 09/20/01 This article from the Chicago Tribune, is an excellent statement from a well respected structural engineer, R. Shankar Nair, former chairman of the Council on Tall Buildings and Urban Habitat on what could have been expected and what could not have been expected. I believe everyone should read his statement.
  • 09/27/01 Link Corrected: 09/25/01 There are a number of other interactive links from the New York Times that start with the "Mapping the Surface" page and include a seismographic image of the collapse. (A free subscription may be needed for the NYT) and the New York Times has an article explaining the technology that produced the image.
  • 10/02/01 Some excellent graphics not previously linked to this page from the San Francisco Chronicle show the size relationship of the airplane and the tower floor plane. Scan both forward and backward from this site for other informative graphics.
  • 10/10/01 Les Robertson spoke publicly for the first time this past weekend at the Manchester, NH meeting of the National Council of Structural Engineers Associations. The Wall Street Journal reported on his presentation as did Chris Hewitt, one of the Penn State AE students in attendance.
  • 10/10/01 A semi technical article discussing some approaches to high rise building design approaches from the Wall Street Journal.
  • 10/03/01 The New York Times of September 18 published an article discussing the fire response of the WTC that, in my view had some misinformation so I had not previously linked it. I have recently received a response letter to the editor form Manny Herrera, a Fire Protection Consultant so I have included both. Be sure to read Mr. Herrera's response regarding how a concrete building might have performed.
  • 10/18/01 An excellent article written by G. Charles Clifton, a structural engineer with HERA presents what is perhaps a new perspective on the collapse. This article is well worth reading. (*.pdf format)
  • Jon Magnusson, chairman-CEO of Seattle based Skilling Ward Magnusson Barkshire Inc., one of the successor firms to the engineer of record for the World Trade Center, Skilling Helle Christiansen and Robertson comments on just how good the structural system of the WTC towers really performed. (Taken from ENR)
  • Data on the Boeing 757, size etc. is taken from the Washington Post.
  • USA Today Time-line of the attack and the period afterward.
  • Engineering News Record (ENR) (9/11/01) web site has some opinions. (I am not sure that the Penn Staters will agree with all that they say here. (LFG))
  • CNN Chat with Tod Rittenhouse of Weidlinger Associates with some clear discussions.
  • 10/18/01 One month after the attack on the World Trade Center, A panel of Boston area-based civil and structural engineers convened at M.I.T. to discuss the fate of the superskyscrapers. One member of that panel was Robert McNamara, PSU AE '63.
  • 10/18/01 Engineers from M.I.T. provide their input in this article from ChicagoLandConstruction.com
  • 11/28/01 A Scientific American article reporting on the MIT meeting.
  • 11/28/01 MIT Technology Review also reports on the collapse. This is not a new article, just newly listed here with old information. It contains links to other MIT faculty opinions on the collapse.
  • 10/29/01 Although not actually a discussion of an analysis of the collapse, this video clip of a news report from the SEAOC 2001 San Diego Convention is interesting. <RealMedia> < WindowsMedia>
  • 10/30/01 The October issue of STRUCTURE magazine has two articles on the WTC. The Cover(*.pdf) shows an impressive view of the wreckage while one article (*.pdf). by W. Gene Corley, discusses the search for answers to the structural response. (The second article (*.pdf) is linked here and below.)
  • 11/08/01 Jon Magnusson, Chairman and CEO of Skilling Ward Magnusson Birkshire Inc. published an editorial (*.pdf) in the October issue of STRUCTURE.
  • 11/12/01 Some of the information being gathered by the ASCE/SEI investigation team and, their tentative conclusions, are now being made public. This NYT article "Why Trade Center Towers Stood, Then Fell" provides an up to date the review of what these experts now believe.
  • 11/19/01 An excellent article from the November 19, 2001 issue of the New Yorker magazine discusses the World Trade Center, its structural concepts, the designers, the collapse and the investigation. This is one of the must read articles.
  • 11/30/01 Although many have known for some time that WTC 7 contained large amounts of diesel fuel, I believe this is the first article to bring the collapse of WTC and its suspected cause to the forefront.
  • 12/05/01 US News and World Report attempt to describe the collapse through graphics.
  • 12/06/01 Using CAD simulation tools from automotive crash study techniques to simulate an aircraft smashing into buildings.
  • 12/07/01 The Chicago Tribune article quoting Gene Corley, had of the ASCE Investigating Team, discussing the current theories of the collapse of the towers.
  • 12/10/01 The graphics accompanying the Chicago Tribune article about the investigation provides some insights into the construction of the WTC and the theories of the collapse.
  • 12/12/01 An ENR editorial warns about drawing premature conclusions and changes in future codes as a reaction to the WTC collapse.
  • 12/13/01 An expert in fire protection has said that inadequate or faulty fireproofing that had gone unrepaired for years may have played a role in the failure of the two 110-story buildings.
  • 12/13/01 An AP article on the role of the fireproofing in the collapse.
  • 01/09/02 According to the NYTimes, NYC had been warned of the danger of the location of the fuel tanks at WTC 7
  • 01/09/02 on Dec. 20, 2001, USA Today reviewed the events of Sept. 11 from the perspective a 3 months distance and reveals some of the more accurate information on what happened, how many lives were lost and how the evacuation progressed. This page also includes an interesting interactive graphic link describing the losses.
  • 01/16/02 Richard Gewain, a member of the federally designated panel of engineers probing the collapses of the WTC Towers said "Conceivably, the building would have collapsed without the fire."
  • 01/18/02 An excerpt from Construct in Steel (*.pdf) Vol 14, N3, September 2001 by the Australian Institute of Steel Construction.
  • 02/11/02 CBS announced yesterday that it would broadcast a two-hour documentary special on March 10 culled from the videotape footage shot inside the World Trade Center by two young French filmmakers during the terrorist attack on Sept. 11.
  • 03/04/02 Robert DeNiro will host "9/11" the exclusive insider's account of the World Trade Center attack from French filmmakers Gedeon and Jules Naudet. DeNiro is a prominent actor, director and producer living in New York City and is a co-founder of the Tribeca Film Center which is located just a few city blocks from ground zero.
  • 03/16/02 The CBS documentary "Experiencing 9/11 from the Inside"
  • 03/16/02 Firefighters comment on the CBS documentary.
  • 02/12/02 The New York Times presents a "A Wounded City" - A Photographers Journal with commentary and photographs from some 7 of their photojournalists. You may click on the images as the audio is being played.
  • 02/12/02 The year in pictures - AFTER Sept 11, 2001, from the New York Times.
  • 02/12/02 360 degree views of NYC before and after Sept. 11.
  • 03/04/02 Two studies try to establish speed of jets as they hit the WTC towers.
  • 03/04/02 The National Transportation Safety Board has released none of the techincal information related to the Sept. 11 crashes.
  • 04/16/02 Les Robertson reflects on the rise and fall of the World Trade Center towers. From The Bridge, a publication of the National Academy of Engineering. The previous link does not include the figures. The full volume of the journal. with figures is available as a *.pdf download.
  • 05/15/02 HBO begins the editing of its special, narrated by former Mayor Rudolph W. Giuliani, "In Memoriam: New York City, 9/11/01" to be aired May 26 at 9 p.m.
  • 05/29/02 Review of HBO special.
  • 05/29/02 Elevator machinery protected one exit stairway and saved 16 people.
  • 05/29/02 USAToday graphic showing how elevator equipment protected one stairway.
  • 05/30/02 Fighting to Live as the Towers Died is a haunting chronicle of the last 102 minutes before the towers fell, built on scores of phone conversations, email and voice messages. The site also includes an interactive presentation inside the towers and a chronology of the events of September 11.
  • 05/30/02 Accounts from the North Tower and the South Tower.
  • 07/24/02 The events of 9/11 exposed deadly flaws in rescue plans. This page includes several interactive graphics showing locations of Police and Fire Department activity prior to collapse, audio of the emergency dispatches, and locations of units which suffered losses.
  • 07/24/02 Disaster planner points to lessons learned.
  • 07/24/02 The NOVA companion web site to "Why the Towers Fell."
  • 08/30/02 The AIA has a DVD of the NOVA program available for rental.
  • 08/19/02 Lost voices of Firefighters - some reached much higher floors than previously thought.
  • 08/19/02 New York's firefighters were hindered by a series of failures in their response to the attack.
  • 08/26/02 An older article on the squabbles between police and firefighters.
  • 10/26/02 Report in NYT on claim by Charles Thornton that Petronas Towers would have withstood the terrorist attach.
  • 10/26/02 Expert Report disputes ASCE/FEMA report conclusions on cause of collapse of Twin Towers.
  • 10/24/02 Press Release issued by Silverstein Properties on further studies that they had conducted on the WTC collapses and its results
  • 10/26/02 NYT article making a comparison between the WTC and Petronas Towers. Makes some good points and questions any conclusion that Petronas would have withstood the attach any better than WTC.

Building condition around WTC site

  • There are many false rumors about the condition of other buildings in the area of the Twin Towers. "In fact, there is no evidence to support all the various speculation, such as rumors that 1 Liberty Plaza or the American Express tower could come down, which is definitely not true." according to Richard Tomasetti. A good summary of some of the buildings conditions is provided by the New York Times.
  • 09/24/01: 09/20/01 -09/19/01 A map indicating the status of the buildings around ground zero. I do not know the source so I can not attest to the structural engineering accuracy of this information but at least it is a good representation of the location.
  • 09/21/01 Buildings.com has a listing of the square footage of space destroyed or damaged in lower Manhattan. There is no indication that this summary has been coordinated with the professionally conducted structural assessments but it still provides some perspective to the problem.
  • 09/24/01 The Washington Post has a fine diagram of the underground condition around Ground Zero, as of Sept. 21, 2001
  • 09/25/01 09/24/01 Light Detecting and Ranging used to measure the rubble as reported by CNN. The same image, with some interactive views of the site before the attack is available from the New York Times. (A free subscription may be needed for the NYT)
  • 09/27/01 added link: 09/24/01 CNN.com has an excellent 3-D graphic of the status of buildings in lower Manhattan.
  • 09/28/01 ENR reports in its Sept. 24 cover story that most surrounding buildings are safe.
  • 10/08/01 The Structural Engineers Association of New York has a map and list of assessed buildings as of September 22, 200. You may also go directly to their web page.
  • 10/08/01 Preservationists say most of the 67 city landmarks below Chambers Street emerged ash-laden but unscathed from the attack. But they want to assess several buildings close to the collapsed towers, where access is still limited.
  • 10/05/01 27.5 Million square feet of Commercial Office Space Believed Destroyed or Damaged in Lower Manhattan. As reported by Buildings.com on Sept. 14.
  • 10/05/01 Four Percent of Manhattan's Total Office Space Was Destroyed in the World Trade Center Attack as reported by Buildings.com
  • 10/18/01 One Liberty Plaza is scheduled to reopen on Oct. 22 with a ribbon cutting ceremony. There had been many rumors that the building was in danger of collapse.
  • 11/30/01 Verizon has nearly all of the voice circuits knocked out by the WTC attacks restored and is now planning the rebuilding of its system.
  • 11/30/01 The reopening of three subway stations damaged by the destruction of the World Trade Center is at least three years away, a chief engineer at New York City Transit said.
  • 12/05/01 December 4 update on the condition of 90 West Street with reference to a few others. This classic building performed admirable even though many levels of spandrel beams were distorted in the collapse of the WTC.
  • 12/06/01 The graphics with the above NYT article provided a view of the physical relationship of 90 West Street to the other buildings. Go to the "Fireprofing" tab for a comparison of the fireproofing systems for 7 WTC and 90 West St.
  • 12/06/01 This article discusses the retail situation in lower Manhattan.
  • 12/06/01 ENR reports that NYC is ready to give back to their owners some of the buildings compromised by the Sept. 11 attack.
  • 01/09/02 As of December 19, ABC reports that the fires at the WTC site are finally out.
  • 01/09/02 NYC has started to build viewing platform around the WTC site to accommodate the publics desire to see ground zero.
  • 01/16/02 The Winter Garden looks to a rebirth through its restoration. This includes a very fine graphic.
  • 01/16/02 Plans to rebuild WTC 7 with tentative ground breaking set for September 11, 2002.
  • 02/11/02 The World Trade Center station of the E subway line reopened Monday, January 28 for the first time since Sept. 11.
  • 02/11/02 The most extraordinary thing about the recently reopened World Trade Center subway station is how hauntingly ordinary it can look.
  • 02/11/02 The Ritz-Carlton, New York Battery Park hotel plans to open.
  • 02/11/02 Parents and teachers at Public School 89, which was evacuated after the terrorist attack of Sept. 11, have voted by a wide margin to return to their school on Feb. 28.
  • 02/11/02 While redevelopment of the World Trade Center site is scheduled to begin soon, other involved groups fear the effort may be rushed.
  • 02/11/02 For a while on Monday, February 4, office workers near ground zero could entertain the illusion that life was back to normal at the World Financial Center.
  • 02/11/02 SouthWest NY in 2 World Financial Center, which was damaged on Sept. 11, has reopened.
  • 02/12/02 At least 22 of the 45 buildings seriously damaged on Sept. 11 remain closed.
  • 03/04/02 The tenants of 125 Cedar Street, one block south of ground zero, are excited and fearful to return home.
  • 03/04/02 Public School 89 students arriving at their school for the first time since the September attack were mostly jubilant.
  • 03/23/02 The steel began going up into the ravaged eastern facade of the Winter Garden of the World Financial Center.
  • 04/22/02 Redesign of the eastern facade of the Winter Garden has been released.
  • 04/16/02 St. Paul's Chapel on Broadway at Wall Street closed its doors to the public and opened them to the firefighters, police and other workers at the nearby World Trade Center site. Staffed by volunteers, the chapel has provided food and refuge around the clock ever since.
  • 04/16/02 Within a few weeks, clean-up of the exteriors of many of the buildings around the WTC site will begin.
  • 04/18/02 I had not seen much written about St. Nicholas Greek Orthodox Church previously. The tiny church building was crushed on September 11. Rebuilding Wall Street, (*.pdf) April 17, 2002 issue has an article about the church and the future the parishioners hope to rebuild.
  • 04/18/02 The Greek Orthodox Archdiocese Of America reports on St. Nicholas Greek Orthodox Church, 155 Cedar St., NY, NY.
  • 04/18/02 The St. Nicholas Greek Orthodox Church web site includes photos of the church as well as the site after Sept. 11.
  • 04/18/02 Photographs of St. Nicholas Greek Orthodox Church in the shadow of the WTC.
  • 04/18/02 Wall Street Journal article with map showing location of St. Nicholas Greek Orthodox Church and the New York Time published a brief article.
  • 04/18/02 This article on St. Nicholas is essentially the same as those above. It includes a photograph of the collapsing towers behind St. Peter's Roman Catholic Church which is uptown from the World Trade Center on Church Street.
  • 05/30/02 Bankers Trust Building at 130 Liberty Street remains deserted but still a tribute to the structural strength of this ordinary office building.
  • 06/10/02 Victim's remains found in the clean-up of buildings surrounding Ground Zero.
  • 06/21/02 The rebuilding of the Winter Garden continues, It may be that this provides a memorial to those lost at Ground Zero without all the turmoil taking place surrounding an "official" memorial.
  • 07/08/02 No remains found in Deutsche Bank building across from WTC site.

WTC Below grade conditions

  • 09/18/01 The New York Times has published an extensive article on the foundation of the entire World Trade Center complex basement structure, reporting on input from George J. Tamaro, a staff engineer for the Port Authority in 1967, when he helped build the World Trade Center's basement, a 16 acre, 70 foot deep hole in the ground.
  • 09/26/01 Concern has been expressed over the stability of the "bathtub" substructure of the WTC as the debris are removed. Two firms have been hired to guide the demolition and subgrade consideration as reported by ENR.
  • 10/08/01 Visual surveys indicate roughly 50% of the seven-level "bathtub" basement structure of the World Trade Center is now rubble as a result of the impact of the collapse of the twin 110-story towers, from ENR 10/08/01.
  • 10/08/01 Along with the basement structures, the subways have sustained significant damage. Access is now showing the extent of the needed repairs there.
  • 10/01/01 New York Times article with graphic on what it will take to rebuild the subways under the WTC.
  • 10/10/01 The basement structure gets further assessment as reported in this New York Times article.
  • 10/25/01 The process of stabilization of the "bathtub" has begun according to ENR.
  • 11/01/01 Two of the NYC Subway lines are set to reopen well on advance of their anticipated date.
  • 11/02/01 The extensive underground mall area is now slowly being reached. Millions of Dollars of gold and silver are safe in a massive vault.
  • 11/19/01 About 40 of the estimated 1100 tiebacks needed to complete the cleanup of the WTC site have been installed in recent weeks.
  • 12/05/01 As the clean up continues in depth focus is being directed to the "bathtub" foundation.
  • 01/09/02 Subway line damaged in attack may reopen much earlier than originally anticipated, according to Jan 4, 2002 NYT.
  • 02/11/02 Damage to the underground wall that helps hold back the Hudson River at the World Trade Center site has city officials considering the installation of a new concrete wall, a large job given the enormous size of the so-called bathtub.
  • 03/16/02 Sections of the "bathtub" collapse.
  • 03/23/02 Workers are hurrying to shore up and patch a 90-foot-wide gash in the bathtub.
  • 04/16/02 The engineer who oversaw the construction of the World Trade Center "bathtub" describes the recovery efforts. From The Bridge, a publication of the National Academy of Engineering. The previous link does not include the figures. The full volume of the journal. with figures is available as a
Geplaatst door de Elf September Onderzoeksgroep op July 19, 2004 9:05 AM | |


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  • Debunking 911 - uitgebreide site over ondermeer het knikken van de stalen constructies van de WTC torens.


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