Small list of Engineers

MIT scientists:

Eduardo Kausel
Professor of Civil and Environmental Engineering - MIT
* C.E. 1967, University of Chile
* M.S. 1972, MIT
* Sc.D. 1974, MIT

John E. Fernandez
Associate Professor of Building Technology - MIT
1989--MArch, Princeton University
1985--BSAD, MIT
Awards or Positions:
2003--Honorable Mention, International Competition for the Design of Ephemeral Structures
2002--Hass Award: Laminated Glass Research
2002--Class of 1957 Career Development Professorship
2001--Graduate Student Council Award for Teaching
2001--American Collegiate Schools of Architecture, Service Award for Conference Co-Chair of the 2000 ACSA Technology Conference
2000--3M Innovation Award
1998--New York City AIA: Design Citation, Columbia University Law School with Polshek and Partners
1998--New York State AIA: Design Citation, Columbia University Law School with Polshek and Partners
1998--New York State AIA: Design Citation, New York Times Printing Plant with Polshek and Partners
1988--Master's Thesis Prize, Princeton University, School of Architecture: Butler Traveling Fellowship

Tomasz Wierzbicki
Professor of Applied Mechanics Director, Impact and Crashworthiness Laboratory - MIT
Ph.D. in Applied Mechanics, 1965 Institute of Fundamental Technological
Research, Warsaw, Poland
S.M. in Engine Design, 1960 Warsaw Technical University, Warsaw, Poland
B.S. I took a unified program that led directly to the Master of Science
Awards or Positions:
Maximilian T. Huber Award for the best work in Mechanics, Polish Academy of Sciences, 1974
Chairman of the Euromech Colloquium No. 121 on "Dynamics and Crushing of Plastic Structures", 1978
Chairman of the Summer School on "Dynamics of Plastic Structures", International Center for Mechanical Sciences, Udine, Italy, 1979
Polish Academy of Sciences award for the book "Design of Structures to Dynamic Loads", 1979
Co-chair, First International Symposium, "Structural Crashworthiness", UK, 1983
Co-chair, Second International Symposium, "Structural Failure", Cambridge, MA, 1988
Alexander von Humboldt Foundation, Senior US Scientist Award, 1988-1989
Co-chair, Third International Symposium, "Structural Crashworthiness and Failure", UK, 1993
Member of the Editorial Boards of the International Journal of Impact Engineering and International Journal of Vehicle Design

Liang Xue
Ph.D. Candidate of Mechanical Engineering - MIT
BS in Mechanical Engineering, Shanghai Jiao Tong University, 1994
BS in Computer Sciences, Shanghai Jiao Tong University, 1994
MS in Mechanical Engineering, Shanghai Jiao Tong University, 1997
MS in Ocean Engineering, Massachusetts Institute of Technology, 2003
Awards or Positions:
Wunsch Foundation Silent Hoist and Crane Award, 2006;
Ziqiang Award , 1997 ;
Guanghua Award , 1996 ;
Outstanding Graduate , 1994 ;
Outstanding Performance Award , 1991-4;
Model Student , 1993 ;
Outstanding Student , 1992

Meg Hendry-Brogan
Ocean Engineering Graduate Student - MIT

Ahmed F. Ghoniem
Professor of Mechanical Engineering - MIT
B.S. in Mechanical Engineering, July 1973, Cairo University, Egypt
M.S. in Mechanical Engineering, October 1975, Cairo University, Egypt
Ph.D. in Mechanical Engineering, June 1980 , University of California, Berkeley
Awards or Positions:
Sep. 83 - Current Department Undergraduate Faculty Advisor
Sep. 84 - Sep. 87 Department Graduate Committee
Department Graduate Advisor
Sep. 85 - Sep. 90 Mathematics Minor Advisor
Sep. 85 - June 86 Department Seminar Chairman
Sep. 87 - Sept. 88 Department Admission Committee
Sep. 90 - Current Computers in Education
Nov. 91 - Jan. 92 Ad hoc Committee on Promotion
1991 –1992 Committee to establish PEEER
Jan. 92 Current Department Admissions Committee
Jan. 90 - May 94 SAL Seminar Series
Jan. 94 - June 94 Search Committee Chair
Jan. 94 - 1995 Ad hoc Committee on the Core Development
Jan. 94 - Current Space Committee
Sep. 95 - June 98 Committee on Undergraduate Programs
June 96 - Current Head of Thermo Fluids Sciences Division
Sep 99 - Sep 00 Committee on Curricula, member
Sep 00 Committee on Curricula, Chair

Oral Buyukozturk
Professor of Civil and Environmental Engineering - MIT
* Ph.D. 1970, Cornell University
* M.S. 1969, Cornell University
* M.S.C.E. 1963, Istanbul Technical University, Istanbul, Turkey
Awards or Positions:
Infrastructure Science and Technology Group

Franz-Josef Ulm
Professor of Engineering Mechanics and Materials - MIT
* Diplom Ingenieur (M.Sc.) 1990, TU Munich
* Docteur-Ingenieur (Ph.D.) 1994, ENPC, Paris
* Habilitation 1998, ENS de Cachan

Yossi Sheffi
Professor of Engineering Systems - MIT
B.Sc. Technion in Israel - 1975
S.M. - MIT, 1977
Ph.D - MIT 1978
Awards or Positions:
Director of the MIT Center for Transportation and Logistics
Founder: MIT Master of Engineering in Logistics program
Founder: MIT:Zaragoza Program
Plaza2006 Award
Distinguished Service Award (Council of Supply Chain Management Professionals) - 1997
Life Fellow of Cambridge University's Clare Hall College

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NIST scientists:

Dr. H.S. Lew – Senior Research Engineer. PhD Civil Engineering, BS in Architectural Engineering. ASCE Fellow.
With NIST: Structural Engineering, Earthquake Engineering, Building and Fire Research.
http://www2.bfrl.nist.gov/profiles/p...p?lastname=Lew
(his full profile)

Richard W. Bukowski – Senior Research Engineer. BSc Electrical Engineering.
With NIST: Co-ordinator of Building and Fire Research Lab.
http://www2.bfrl.nist.gov/profiles/p...tname=bukowski
(his full profile)

Dr. Fahim H. Sadek – PhD Mechanical Engineering SMU
With NIST: Research Structural Engineer
http://www2.bfrl.nist.gov/profiles/p...lastname=sadek
(his full profile)

Dr. Frank W. Gayle – PhD Metallurgy MIT, MSc Materials Science, BSc Civil Engineering.
http://wtc.nist.gov/pi/wtc_profiles.asp?lastname=gayle
(his full profile)

Dr. David D. Evans – PhD in Engineering (Fire protection)


Dr. William Grosshandler – PhD Mechanical Engineering UC Berkley
With NIST: Head of Building and Fire Research
http://www2.bfrl.nist.gov/profiles/p...e=grosshandler
(his full profile)

Dr. Richard G. Gann – PhD Physical Chemistry MIT
With NIST: Senior Research Scientist – Integrated Performance Assessment
http://www2.bfrl.nist.gov/profiles/p...?lastname=gann
(his full profile)

Dr. John L. Gross – PhD Structural Engineering, BSc/MSc Civil Engineering Cornell
With NIST: Research Engineer – Materials and Construction Research Division
http://www2.bfrl.nist.gov/profiles/p...lastname=gross
(his full profile)

Dr. Therese P. McAllister – PhD Structural Engineering John Hopkins
With NIST: Senior Structural Engineer.
http://www2.bfrl.nist.gov/profiles/p...ame=mcallister
(her full profile)

Jason D. Averill – MSc Structural Engineering (working on PhD) John Hopkins
With NIST: Research Engineer
http://www2.bfrl.nist.gov/profiles/p...stname=averill
(his full profile)

J. Randall Lawson – BA, BSc Industrial Education, AA Computer Science and Math
With NIST: General Physical Scientist
http://www2.bfrl.nist.gov/profiles/p...astname=lawson
(his full profile)

Shyam Sunder, Sc.D.
Indian Institute of Technology, Delhi, B. Tech., (Honors), Civil Engineering, 1977
Massachusetts Institute of Technology, S.M., Civil Engineering, 1979
Massachusetts Institute of Technology, Sc.D., Structural Engineering, 1981

James Quintiere, Ph.D. professor of engineering, University of Maryland
Educated as a mechanical engineer
B.S. degree from New Jersey Institute of Technology (1962)
M.S. (1966), Ph.D. (1970) from New York University.
http://www.enfp.umd.edu/faculty-profiles/quintiere.html



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FEMA/ASCE Pentagon Team Scientists/Engineers
--------------------------------------------

Mete A. Sozen, Ph.D., S.E.
Kettlehut Distinguished Professor of Structural Engineering, Purdue University
Specialty: Behavior of reinforced-concrete structures

Paul F. Mlakar, Ph.D., P.E.
Team Leader
Technical Director, Army Engineer Research and Development Center
Specialty: Blast-resistant design

Donald O. Dusenberry, P.E.
Principal, Simpson Gumpertz & Heger, Inc.
Specialty: Blast effects and structural design

James R. Harris, Ph.D., P.E.
Principal, J.R. Harris & Company
Specialty: Structural engineering

Long T. Phan, Ph.D., P.E.
Research Structural Engineer, National Institute of Standards and Technology
Specialty: Concrete, structural and fire engineering

Gerald Haynes, P.E.
Fire Protection Engineer, Bureau of Alcohol, Tobacco and Firearms
Specialty: Fire protection


FEMA/ASCE WTC Team Scientists/Engineers
---------------------------------------


W. Gene Corley, Ph.D., P.E., Lead
Senior Vice President
Construction Technologies Laboratories, Skokie, Illinois
Expert in building collapse investigations; principal investigator, Murrah Federal Office Building Study.

William Baker, P.E., S.E. Partner
Skidmore Owings & Merrill LLP
Expert in tall-building design.


Jonathan Barnett, Ph.D.
Professor, Center for Fire Safety Studies
Worcester Polytechnic Institute, Worcester, Massachusetts
Expert in building fire safety design and fire computer modeling.


David T. Biggs, P.E.
Ryan-Biggs Associates, Troy, New York
Expert in facades.

Bill Coulbourne, P.E., S.E.
Principal
URS Corporation, Gaithersburg, Maryland

Edward M. DePaola, P.E.
Partner
Severud Associates Consulting Engineers, New York, New York
Expert in structural engineering.

Robert F. Duval
Senior Fire Investigator
National Fire Protection Association
Expert in fire investigations.

Dan Eschenasy
Chief, Structural Engineering
City of New York
Dept of Design and Construction

John T. Fisher, P.E.
Joseph T. Stuart Professor of Civil and Environmental Engineering
Lehigh University, Bethlehem, Pennsylvania
Expert in metallurgy and connections.

Richard G. Gewain
Senior Engineer
Hughes Associates, Inc., Baltimore
Expert in fire engineering.

Ramon Gilsanz
Managing Partner
Gilsanz Murray Steficek, New York, New York
Expert in structural engineering.

John L. Gross, Ph.D., P.E.
Leader
Structural Systems and Design Group Building and Fire Research Laboratory
National Institute of Standards and Technology, Gaithersburg, Maryland
Expert in steel design and fire-structure interaction.

Ronald Hamburger, P.E., S.E.
Senior Vice President
EQE Structural Engineers Division, ABS Consulting, Belmont, California
Expert in structural analysis and design.

Nestor Iwankiw
Vice President, Engineering and Research
American Institute for Steel Construction, Chicago, Illinois
Expert in steel design.

Venkatesh Kodur, Ph.D., P.E.
Institute for Research in Construction
National Research Council of Canada, Ottawa, Ontario
Expert in fire effects on materials.

Eric Letvin
Department Head, Hazards Engineering Group
Greenhorne & O'Mara, Greenbelt, Maryland

Jon Magnusson, P.E.
Chairman of the Board, Chief Executive Officer
Skilling Ward Magnusson Barkshire, Inc., Seattle, Washington
Expert in structural analysis and high-rise design.

Christopher E. Marrion, P.E.
Fire Strategist
Arup Fire, New York, New York
Expert in fire engineering.

Therese P. McAllister, Ph.D., P.E.
Senior Structural Engineer
Greenhorne & O'Mara, Greenbelt, Maryland

James Milke, Ph. D., P.E.
Professor, Department of Fire Protection Engineering
University of Maryland
Expert in fire resistance analysis.

Harold E. "Bud" Nelson
Senior Research Engineer
Hughes Associates, Inc.

James A. Rossberg, P.E.
Director, Structural Engineering Institute
American Society of Civil Engineers (ASCE), Reston, Virginia

Saw-Teen See, P.E.
Managing Partner
Leslie E. Robertson Associates, New York, New York
Expert in structural analysis and high-rise design.

Robert Smilowitz
Principal
Weidlinger Associates, New York, New York
Expert in blast effects.

Bruce Swiren
Hurricane Program Manager, Region II
Federal Emergency Management Agency, New York, New York

Paul Tertell, P.E.
Program Manager, Building Performance Assessment Team
Federal Emergency Management Agency, Washington, D.C.

--------------

Allyn E. Kilsheimer, P.E. CEO, KCE Structural Engineers PC
(first structural engineer to arrive at Pentagon crash site)

Christoph Hoffmann, Ph.D.
Professor of Computer Science - Purdue
Ph.D., University of Wisconsin, 1974.
(worked on comp models of Pentagon)

The search for answers in the rubble of the Twin Towers

The search for answers in the rubble of the Twin Towers
Apr 1, 2002 12:00 PM
Paul Rothman

The crumbled remains of the World Trade Center hold clues about how to enhance fire safety, structural engineering and security for present and future high-rises.

Researchers at the National Institute of Standards and Technology (NIST) are examining the charred rubble, hoping to unearth a world of knowledge.

The NIST, a government agency, provides measurements, standards and technical advice to federal, state and local agencies and the private sector to protect U.S. citizens from terrorist, military, natural disaster and other types of threats. In a March statement before the U.S. House of Representatives' Committee on Science, NIST Director Dr. Arden L. Bement Jr., outlined the NIST's role in the aftermath of the terrorist attacks.

“The tragedy that the United States experienced on Sept. 11 was unprecedented when compared to any prior accident, natural disaster or terrorist/war attack,” Bement says. “The collapse of the twin World Trade Center towers was the worst building disaster in human history. Engineers, emergency responders and the nation did not anticipate — and were largely unprepared for — such a catastrophe.”

Bement highlighted the technical priorities in examining the remains of the towers:

• To establish the probable technical causes of the collapse and derive the lessons to be learned;

• To develop and disseminate immediate guidance and tools to assess and reduce future vulnerabilities; and

• To produce a technical basis upon which cost-effective changes to national practices and standards can be developed.

While the formal investigation and research have just begun, potential benefits are easy to envision. Above all, the NIST's findings — which will come at the conclusion of a 24-month study — could mean adjustments to current fire codes and regulations.

“We put those lessons learned to work,” says NIST spokesman Michael Newman. “We provide the data to groups which can change fire codes and building standards.

“But you never go in guessing,” he adds. “Our part is to try to determine what were the conditions that led to the collapse.”

The focus of the NIST study will be the twin towers because, according to Bement, the collapse of the towers was the triggering event that caused much of the collateral damage to adjacent properties. Also, the NIST will focus on examining procedures and practices used to provide structural reserve capacity to resist blasts, explosions, accidental fires and other disasters; and to study the effectiveness of fire fighting technologies and practices for tall buildings.

According to Bement, the objectives of the NIST investigation would be to determine:

• Why and how the towers collapsed;

• Why the injuries were so high or low depending on location, including technical aspects of fire protection, response, evacuation, occupant behavior and emergency response;

• Whether or not state-of-the-art procedures and practices were used in the design, construction, operation and maintenance of the towers; and

• Whether there are new technologies or procedures that should be employed in the future to reduce the potential risks of such a collapse.

Scientists from the NIST will conduct the study in cooperation with consultants from a range of agencies that include the New York Port Authority, Federal Emergency Management Agency (FEMA), the Tall Building Council, the Society of Fire Protection, the American Institute of Steel Construction and others.

In its preliminary stages, scientists and researchers will construct a computer model of the likely conditions inside the buildings following the collisions using a program called a Fire Dynamic Simulator or one called SnakeView.

“The model is constructed using mostly visual information,” Newman says. “Using a model looking at the fire and smoke as it is portrayed visually, the researchers can try to step back and determine what would have led to the collapse.

“They try to match [the pieces] with what they see in the models, and use the computer to go backward in time,” Newman continues. “Pieces of steel can show warping and give an indication of how hot it really was inside. With that, we can determine how the heat affected the infrastructure.”

Researchers then sift through the rubble to confirm their hypotheses. Already, 50 to 60 pieces from the towers have been transported to NIST headquarters in Gaithersburg, Md.

“The last step will be to disseminate all the information and make sure these lessons learned don't go to waste,” Newman says. “It was such a tragic event, but in effect, it's an unusual learning experience. Something like this is unprecedented, and will prove very valuable in future design and code regulations.”

WTC Lessons For Future Disasters

WTC Lessons For Future Disasters

Report Says Why Twin Towers Fell, Calls For New Evacuation Plans

WASHINGTON, April 6, 2005 The south tower collapses as smoke billows from both towers of the World Trade Center on Sept. 11, 2001. (AP) Quote The lead investigator says the twin towers collapsed because the impact of the planes shook loose the steel skeleton's fireproofing material, which normally would be able to withstand heat as intense as 800 degrees. (AP) The Sept. 11, 2001, attack on the World Trade Center is more than a tragic day in American history. It continues to be an opportunity for lessons to be learned. In a batch of government reports released Tuesday, engineers say they know why the twin towers fell down, how things went wrong during the evacuation, and believe new thinking is needed on how to evacuate people from endangered skyscrapers and how to get rescuers into them more quickly. The reports by the National Institute of Standards and Technology also detail how early decisions played a key role in determining who died and who survived. A total of 2,749 lives were lost when the two hijacked jets were crashed into the twin towers. The NIST reports note that expectations of how quickly people move down stairwells have been based on "phased" evacuations, and not the full-scale evacuation of the type attempted at the World Trade Center. "The average surviving occupants moved slower down stairs and through stairwell exits than previously recorded for a non-emergency evacuation," investigators concluded. To underline the importance of the finding, NIST estimated that had the buildings been hit at a time when they were full, as many as 14,000 people may have died. In Tower 1, the average survivor took 48 seconds to descend a flight of stairs, or about half the slowest evacuation speed calculated in a current fire safety handbook used by engineers in designing buildings, the report found. The briefing in New York was conducted by Shyam Sunder, the lead investigator for the agency's building and fire safety investigation into the disaster. The buildings would not have collapsed if the fireproofing material surrounding the steel had not been stripped away by the impact of the planes, Sunder said. Without that stripping effect, the intense heat of up to 800 degrees Fahrenheit would not have been enough to bring the buildings down. Sunder added, however, that it would not have been reasonable for engineers to have installed fireproofing designed to sustain the impact of a fuel-laden jetliner. The thickness of the fireproofing had been called into question during the course of the two-year investigation; Sunder said far more important was the material's ability to stick to steel. Now there are other ways to put on fireproofing to make it adhere to the steel better. David Collins, a member of the advisory committee that offered suggestions and questions to NIST investigators, said the research showed design and construction of the building were not major contributors to the collapse. "I think everyone took deliberate steps to try to do what was necessary to make the buildings as safe as possible," said Collins, a Cincinnati-based architect. NIST also found the much-documented problems with radio communication and information-sharing among first responders probably led to deaths among emergency personnel. "Lack of timely information sharing and inadequate communication capabilities likely contributed to the loss of emergency responder lives," according to the draft report. Sunder said some of the firefighters they interviewed said they felt they would have gotten better real-time information at home watching TV than what they were told at the scene. The findings are NIST's last step before issuing its final recommendations in June, the culmination of exhaustive research and testing that produced 10,000 pages of data. The other findings - about the emergency response and the behavior of those who were in the building - will be part of the ongoing debate over how to improve skyscraper safety. Investigators have determined that previous expectations about how long people would take to evacuate buildings were not borne out by events at the World Trade Center. The report also noted that some people delayed their evacuation by "milling" in offices, deliberating about what to do, or debating how to find the next stairwell. The previous evacuation models cited in the report are important because architects use them to calculate the capacity needed in stairwells, elevators, and other means of exiting a building. The report also emphasizes the limited ability of rescue personnel to reach higher floors quickly to battle fires and rescue trapped civilians. That proved critical for firefighters who climbed 70 flights of stairs carrying up to 100 pounds of gear - and then tried to battle flames or clear debris once there. Those concerns are spurring a debate both within the NIST group and among the larger fire rescue and construction fields about stairwell and elevator design. The debate centers around whether "fireproof" elevators, designed to resist flames and smoke, should be installed in new buildings, particularly those that rise above 40 or 50 stories, and the best width and location of stairwells. Elevators played a critical, but contradictory, role. In some cases, they helped significant numbers of people get out quickly. For others, they became sealed containers trapping them inside a doomed building. NIST's ultimate goal is to recommend building code improvements.

The World Trade Center: Collapse of the Twin Towers

Terrorist Attacks on New York's World Trade Center Towers

Dateline: September 12, 2001 This article summarizes news reports and commentary at the time of the terrorist attacks on the World Trade Center in New York City. For complete information about the World Trade Center, reconstruction plans, memorials, and other resources related to the September 11 terrorist attacks, visit our World Trade Center Resource Page. Built in the 1970s, World Trade Center Twin Towers in New York City were designed to withstand normal fires and hurricane-force winds. According to some reports, engineers believed that even the impact of a Boeing 707 would not bring down the towers. But the two planes which struck the Twin Towers on September 11, 2001 were much larger than the Boeing jets of the 1970s. Experts say that no engineer could have prepared for the terrorist attack which reduced the World Trade Center to rubble. Indeed, the two towers showed remarkable strength, standing for about an hour after the air strikes. Their ultimate collapse was caused primarily by the jet fuel fire, engineers told reporters for the New York Times. Temperatures soaring from 1,000 to 2,000 degrees caused the steel columns around the tower facades to buckle. With their supports weakened, the concrete-slab floors plunged. The South Tower of the World Trade Center was most heavily impacted on floors 87 through 93. The North Tower was impacted at floors 96 through 103. Because the jets hit the towers near the top, the buildings themselves became their own means of destruction as the weight of many floors crushed downward. Later, falling debris and more fires led to the collapse of the smaller 7 World Trade Center building adjacent to the towers. Designed by Minoru Yamasaki and Associates, the World Trade Center towers utilized tube construction, which was a popular innovation for skyscrapers of the 1970s. Older structures like the Empire State Building use heavy internal supports and thick masonry. In 1945, when a ten-ton B-25 bomber left a 20-foot hole in the landmark skyscraper, the Empire State Building remained standing. But the heavy masonry building would surely not have survived an impact from the larger passenger jets which struck the World Trade Center towers. The Twin Towers were constructed of lightweight steel and glass supported by exterior columns. Each concrete-slab floor was supported by steel trusses with special plates designed to lessen the effect of high winds. Stairs and elevators were supported by columns at the core of the towers. However, the primary support for the towers came from their external sheathing. The demolition of the World Trade Center complex has altered New York's skyline forever. By all accounts, the buildings were miracles of design. Could they have been made stronger or safer? Tell us what you think. Why the World Trade Center Towers Fell Engineers who studied the Twin Towers after the September 11 attacks explain why the buildings stood as long as they did, and why they eventually collapsed. Read more about the construction of the Twin Towers See pictures of the proposed plans for reconstruction on the World Trade Center site.

World Trade Centre Collapse

Reporter: Karina Kelly
Producer: Mick O'Donnell
Researcher: Robert Hodgson

Transcript
Related Info

20 September 2001
As the world still struggles to comprehend the terrorist attacks on New York and Washington, Catalyst investigates why the World Trade Centre towers collapsed the way they did.

Transcript

Narration: When the World Trade Centre was built in 1973, its twin towers were the tallest buildings in the world. Part of their revolutionary new design made them resistant to strong winds and allowed for huge open office spaces. Their strength depended on a steel shell. But no skyscraper in the world is designed to withstand this.

Dr Andy Davids: Steel looses strength and stiffness as its temperature increases past about 1500 degrees. The ferocity of that fire would have been well and truly enough to push it past it's elastic limit if you like and it would have started to soften, and yield


Narration: Dr Andy Davids is one of a handful of people who designs the world's tallest buildings. He's a structural engineer and a friend of Les Robertson who engineered the world trade centre.

Dr Andy Davids: You can see clearly on the footage that that top 25 stories moves almost as a rigid object a single block - it rotates over quite a long way - actually several meters - and drops as a single object. The mass of debris just keeps feeding on itself as it drives down the building and the building just basically unzips.

Narration: So, was the lightness of the steel frame a fatal flaw?

Dr Andy Davids: The failure was due to the consuming nature of the fire and how that weakened the steel structure. I think it's not possible to design a structure that's failure proof.

Narration: Yet, 56 years ago, a near neighbour of the world Trade Centre, withstood another aerial attack. On 18 July, 1945 a B25 bomber flew into the Empire State building in heavy fog.

Dr Andy Davids: It was a much smaller aircraft, a World War two bomber and it weighed about 10 tonne as compared to the 767 as I understand hit the World Trade Centre, which weighed probably to the order of 100 to 150 tonnes.

Karina Kelly: So 10 times bigger - but the Empire state building is still standing today - why is that?

Dr Andy Davids: Yes the structural system of the Empire State is similar in one way to the World Trade Centre in that it is a steel frame, however on the Empire State those steel beams and columns had all been in filled with heavy masonry panels so the building was a very stiff building; a very dense building; had a lot of mass in which to absorb the inertia of the aircraft striking it and limit the damage.

Karina Kelly: Does that mean the Empire State building was a better made building because it could withstand this plane crashing into the side of it?

Dr Andy Davids: Man-made objects such as building are evaluated on many criteria and the striking of a fully loaded aircraft was not one of those criteria.

Karina Kelly: But how would more modern buildings cope with a plane slamming into them?

Dr Andy Davids: The buildings that we design today are probably not much better in that regard. Buildings by their very nature require support along their perimeter and also in the centre. I think the main difference is that the more modern high rise buildings that we design and build today tend to have a large solid reinforced concrete core in the centre, which is the main stability element which prevents the building from moving in response to wind and earthquakes and impacts such as from aircraft.

Karina Kelly: So if you have a core of reinforced concrete then a collapse like that wouldn't happen

Dr Andy Davids: I wouldn't say it wouldn't happen because I think the actual collapse was due to the fire in fact, rather than the impact of the aircraft. So I think that if we are to learn any lessons from this tragedy it would be that the control of massive fire in these types of buildings really needs to be reconsidered.

Dislodged fireproofing felled Twin Towers

Dislodged fireproofing felled Twin Towers

Giles Hewitt Agençe France-Presse

Wednesday, 6 April 2005

Investigator Shyam Sunder presents the 10,000 page report into why the World Trade Center collapsed so quickly after the 11 September 2001 terrorist attack (Image: Reuters/Mike Segar)

The twin towers of the World Trade Center would probably be standing today, if the impact of the planes used in the 11 September 2001 attack had not destroyed fireproofing material, experts say.

After what it described as the most detailed examination of a building failure ever, the US National Institute of Standards and Technology (NIST) says it will be suggesting major changes to the way skyscrapers are built and managed.

The NIST report says the structural impact of the planes and subsequent jet fuel-ignited, multi-floor fires were not in themselves enough to bring the towers down.

"The reason the towers collapsed is because the fireproofing was dislodged," says Shyam Sunder, lead investigator for the NIST building and fire safety investigation into the disaster.

If the fireproofing had remained in place, Sunder says, the fires would have burned out and moved on without weakening key elements to the point of structural collapse.

He drew an analogy with the 2003 Columbia space shuttle disaster when the absence of a small piece of insulation foam, knocked off during launch, allowed fire to seep into the shuttle's entire wing span during re-entry with catastrophic results.

New alternatives to traditional fireproofing should be explored, Sunder says, citing a paint-like substance which, if applied in sufficient layers, would stick "even if a plane hit it".

Nearly 2750 people were killed in the attack on the World Trade Center by members of Osama bin Laden's Al-Qaeda network.

Roughly 17,400 people were in the skyscrapers at the time of the attack, and NIST estimates that the death toll would have been closer to 14,000 if the two towers had been filled to their 50,000-person capacity.

The report says each jet severed perimeter columns, damaged interior core columns and dislodged fireproofing as they penetrated the buildings. The weight carried by the severed columns was spread to others.

View of the last original parts of the World Trade Center as seen in 2004, including the new pedestrian bridge (top), the last remaining original parts (upper) and the new subway station (bottom) (Image: Reuters/Chip East)

Fires caused by the jet fuel were fed by the building contents and oxygen entering through breached walls and windows.

"Floor sagging and exposure to high temperatures caused the perimeter columns to bow inward and buckle, a process that spread across the faces of the buildings," the report says.

"Collapse then ensued."

In examining the emergency services response on 11 September and the evacuation procedures, the NIST report echoes other probes in highlighting a lack of coordination and poor communications equipment.

The report cites one senior emergency services officer inside the north tower of the trade centre as saying he would have known more about what was going on if he had been watching it on television.

"The lack of timely information sharing and inadequate communication capabilities, likely contributed to the loss of emergency responder lives," the report concludes.

The evacuation of the twin towers has generally been called a success, with 87% of the occupants, including more than 99% of those below the floors hit by the planes, managing to get out.

Occupants were often unprepared for the physical challenge of evacuating from higher floors. "It's pretty demanding, especially if you want to do it fast," Sunder says.

The NIST report, running to some 10,000 pages, is still in draft form, with a final version, complete with definitive findings and recommendations, to be released in September.