Conference Facilitator: Thank you Shyam, thank you Jack. We are right on schedule, and we're now ready to begin the public comment segment of this meeting. As a reminder, each speaker will be limited to a nine-minute presentation. To assist each speaker, I'm going to start a countdown clock right in front of you to help you out. You'll watch the time count down. At the two-minute interval, when there's two minutes left, the yellow light will come on so you know you only have two minutes left. And that should also assist you in putting together your final thoughts for the presentation.
Speakers will not be allowed to yield time to others. Due to our tight schedule, questioning the speakers will not be allowed. Also, please refrain from applause and comments during the presentation, so we can hear from our complete list of speakers in our ambitious schedule today. Thank you very much in advance. Our first speaker is Sally Regenhard of the Skyscraper Safety Campaign. Sally?
Sally Regenhard, Skyscraper Safety Campaign: Good morning everyone. I am the Founder and Chairperson of the Skyscraper Safety Campaign. On September 11th, my beautiful son, Probationary Firefighter Christian Michael Otto Regenhard was one of over 2,800 innocent victims lost in the World Trade Center. This event is something that has been completely devastating to families of the victims, and for the last nine months, they’ve gone through an agonizing journey seeking the truth, crying out to make some sense of what happened.
During that time we have turned to the establishment, we have turned to our government, we have turned to the system. I’m here to tell you that initially we were not very successful. We turned to the officials of New York, and you know, many of them turned away from us. But I’m here today to tell you how happy I am that the federal government, our Congress, the Science Committee of the House of Representatives, listened to us, heard our cries, our pleas for an investigation. And I want to tell you that I have to compliment the Science Committee of the House of Representatives, especially Chairman Sherwood Boehlert, the members of the committee from New York, especially Anthony Weiner, and I also want to compliment NIST.
You know, NIST is a agency that most people have not heard of. I never heard of them before, but I’m happy to hear of them now. I want to compliment them, and I want to tell you, especially for the relatives of the victims, that these people are our hope. This study is a hope for us, to find out why our loved ones were annihilated. On September 11th, a group of demonic, cave-dwelling barbarians inflicted the greatest assault to this country, and the greatest loss of life on American soil since the Civil War. We are not accepting this.
Even greater than this tragedy is the fact that even though those buildings were attacked by airplanes, my son, the 343 firefighters, and the majority of the 3,000 heroes who died, the majority of them should not have died, because those buildings should have not collapsed. My son should have been able to save the husband of my Co-Chairman Monica Gabrielle, who was waiting on the 78th floor to be rescued, because he had an injury to his legs. My son should have been able to save him, and he wasn’t able to do so, because the building killed them both.
This is the beginning of a journey, we’re happy to take the journey with Dr. Snell and Dr. Sunder. I want to thank Matt Heyman. I want to thank this organization that has redeemed the government in the eyes of the families of the victims. We were very, very distraught for many, many months, until we realized the government is listening to us. And from this description of the plan and the scope, I feel it is comprehensive, and that it will look at every aspect, especially those trusses, especially the lack of an evacuation plan, especially so many aspects of the unorthodox design and construction, and the lack of fireproofing.
You know I’m just a simple mother from the Bronx, but I know that that building should never have collapsed. I want to safeguard people in the future. Now, looking at my time, I have three minutes left or so?
Conference facilitator: Yes Ma’am
Sally Regenhard: Oh my gosh, I better talk fast. I’m here today to really discuss the aspect that I’m concerned about, and that is the composition of the Federal Advisory Committee. I have been blessed to have a wonderful group of people that have reached out to us, we cried out for people to speak out against what happened, and there are so many good people, so many wonderful, professionals in the field of fire science engineering. The Federal Advisory Committee is a committee that will have a major role in the study. I’m here to say that I have a very big concern with some of the language regarding who can be selected, and who cannot be selected.
I’d like to say that in the language, there are some contradictory references. For example, why is a former NIST employee not eligible to be on this Federal Advisory Committee, but a former NIST recipient of a grant or a contract is eligible? Also, why would a former NIST employee be considered tainted, while current NIST employees are not? Contradictory guidelines and further incongruity is evidenced in the sentence that states, “they must not represent or be affiliated with parties affected directly by the investigations.” I’d like to remind you that every single member of the American Society of Civil Engineers is “affiliated with,” either the engineering, design or construction communities that were involved with the building of the World Trade Center, and therefore, they can be construed as also being parties affected directly by the investigation.
The ASCE conducted the BPAT study, (even though that is not something that I'm a fan of ), and that's further evidence of possible affiliation. Equally important, members listed on the Skyscraper Safety Professional Advisory Panel have made their expertise available to this NIST investigation. They've either given advice to the Skyscraper Safety Campaign or they've even been selected to testify at the House Congressional Hearings.
My organization is a nonprofit pending grassroots organization that has no vested interest other than the safety and security of the American people. Surely, this should not now, or ever, be a basis for exclusion of any of our advisors from the Federal Advisory Committee consideration. On the contrary, Chairman Boehlert of the Science Committee explicitly requested that one of my professional advisors, Prof. Glenn Corbett, and Dr. Arden Bement, the Director of NIST, maintain continuous interaction throughout this investigation. And I can think of no better way to carry out this directive than to have such an eminent professional as Prof. Corbett becoming a member of this Advisory Committee.
I'm going to end by saying that a simple non-professional person such as me surely does not have to remind NIST that the field of fire science and fire science engineering is a very small and limited one. Experts from the fields of structural engineering, architecture, fire protection engineering, firefighting and human behavior have advised the Skyscraper Safety Association. This should not exclude them pro forma.
Finally, prospective candidates from the University of Maryland's department of Fire Protection Engineering, an institution of national prominence and a stone's throw from NIST, should be given great consideration regardless of past NIST employment.
I'd like to ask you in closing, to please review the guidelines as written, or review the interpretation of these guidelines so as not to discriminate against any entity, so that all selections for the Federal Advisory Panel may be equilateral and equitable. And thank you for the wonderful job that you'll be doing.
Thank you.
Conference facilitator: Thank you, Sally. Thank you very much.
Our next speaker is the honorable Anthony Weiner, Member of Congress from the state of New York.
Anthony Weiner, Member of Congress, (D-NY): Good morning and welcome to New York City. Thank you so much for holding this hearing.
I want to thank the members of NIST for giving, frankly, the public their first opportunity to weigh in. In all the hearings that we had in the House of Representatives on this issue we were visited on dozens of occasions by women like Sally Regenhard and other families of victims that were asking some basic questions. But we would misunderstand this issue if we misunderstand the questions.
No one - none of the victims is asking the question: Could this tragic event have been anticipated. Clearly, the answer is no. No one is asking the question about whether or not the craftsmen and workers who built these buildings did a good job. They clearly did.
These proud buildings stood for over an hour. Over 25,000 families are united today and will be eating dinner together tonight because those buildings withstood so much.
But one question is also equally clear, and that is, was the investigation that was done by FEMA thorough and complete. The answer, tragically, is no, because of bureaucratic infighting from the moment of the collapse. There was destruction of evidence. Over 80 percent of the steel from the scene was removed and recycled before any expert had an opportunity to look at it.
There was lack of clear authority that hindered the investigation. And the result was a crime scene investigation that failed to interview key witnesses, failed to collect key evidence, and certainly failed to find the smoking gun.
We in Congress have said that we're never going to allow this to happen again. Congressman Boehlert and I will be passing the first week of July the National Construction Team Act, which will make sure that investigations which will now be headed by NIST, the agency that probably should have been clearly in charge to begin with, will be doing future investigations.
But there was information that has emerged already in the report anecdotally and from experts that will be helpful. It is clear, for example, that the stairwells in the World Trade towers were too closely - were built too closely together. The catastrophic failure of one of them led to catastrophic failures of more than one of them. The result is that three of the four main stairwells in the center of the building were knocked out.
There was a clear failure to provide redundancy in water supply. When the wing of the plane shears one pipe, as it turned out, there was no water. That even if firefighters could reach those upper buildings, there wasn't sufficient water.
There was certainly no consideration of roof access. We heard too many tragic stories of some of the victims trying to get to the roof. One of the first instincts of the New York City Police Department Aviation Unit was to see if they could find access to the roof to help evacuate folks on the upper floors. That clearly was not considered.
And perhaps the most tragic finding is one that we found also in 1993 in the investigation of the World Trade Center bombing. And that is the communication infrastructure built into these large buildings simply was not adequate.
We have now - many of us have seen the tragic images of commanders of the firefighters on the lower floors trying to communicate even to firefighters on floors, 15, 16 and 17, and finding they were unable to. We found tragically that repeaters that were installed in the building after the 1993 bombing were knocked out almost instantly by the electrical cutoffs that happened in so many parts of the building. It is tragic that similar problems that were found in 1993 were not sufficiently addressed in time to perhaps save the hundreds of firefighters that perished on that day.
Your work, gentlemen, is extraordinarily important. We hope to find new building codes, we hope to find regulations that can be put into place for the building of future construction here in cities like New York. And we also hope to be able to learn from your investigations ways to improve emergency management, firefighting and emergency evacuation of tall buildings.
You can throw a stone from here and catch four, five, six, eight, twelve, fifteen, a hundred buildings that provide enormous challenges for emergency workers if there's an accident of any sort, whether it be a bombing or just an earthquake or even just a fire. Hopefully with your work and with the new legislation we'll be passing in early July we won't have these questions rise again.
And let me say a final word about Sally Regenhard and some of the active families that have called this issue to our attention. Frankly put, this legislation would not have been passed empowering NIST without the activity of the families. These families often were derided early on when people said, "Well what do you want? How were we supposed to know those buildings were going to go down?"
They highlighted a need in the law that we have now addressed. I believe that NIST, a group of experts second to none in the world, are uniquely qualified to make sure that future investigations go much more smoothly and regulations, zoning laws and studies that are done in the future ensure that lives are saved.
Thank you.
Conference Facilitator: Thank you, Congressman.
Our next speaker is George Miller, representing the National Association of State Fire Marshals.
George Miller, National Association of State Fire Marshals: Dr. Snell, Dr. Sunder, our association, that is the National Association of State Fire Marshals, represents the most senior fire officials of each of the 50 states and the District of Columbia. Our mission is a simple one: to protect human life, property and the environment from fire. I'd like to thank you for the opportunity to speak this morning and for all that NIST has done and will do in the name of safety.
We believe that the events of September 11th raise two questions. First, what must we as a nation do to prevent terrorism of all kinds? And second, what must we do to make building safer from major fires? I'll confine my comments to the second question.
Apart from whatever damage may have been caused by the collision of the jets, the collapse of the World Trade Center appears to be the result of two related factors. The first was the size of the fire that erupted after the collisions. The second factor was the ability of the towers and their fire protection systems to withstand the fire.
We don't think that the main focus of the inquiry should be about large aircraft accidentally hitting tall buildings. The last time it happened was when the military aircraft hit the Empire State Building during World War II. According to the aviation industry, there are roughly 20 million commercial flights a year; half of which are in the U.S.
The probability of an accidental crash into a tall building is too small to calculate. If we don't want aircraft accidentally hitting tall buildings, we should not build tall buildings near airports. We don't need to pay significant attention to the contents. We don't pay significant attention to the contents of buildings, but we need to.
While the burning jet fuel brought the towers to flashover, the jet fuel was gone quickly. It was the contents - furniture, drapes, wall coverings, cleaning supplies, computer equipment, documents - that kept the fire burning as it did.
We do a great deal to calculate the relationship between fire protection and fuel loads in a warehouse full of goods. But we do little to restrict the fuel load where people work, live and learn.
I don't need to ask whether an undetected wastepaper basket fire might have been capable of bringing a floor of the World Trade Center to flashover. Without a fully functioning, automatic fire sprinkler system, it could.
But if anyone asked me whether such a fire could result in the collapse of tall buildings, it's not a frivolous question.
A recent study by the National Fire Protection Association found out that the rate of on-duty firefighter deaths in structure fires has remained steady for nearly the last quarter century. This has occurred in spite of the decline in U.S. structure fire rates and in spite of improvements in personal protective gear, equipment, training and incident management procedures that have been improved during this time.
Many questions are raised by the NFPA study. One that is relevant in your proceedings is the role played by modern building construction in the development of fires, and in the total or partial collapse of buildings due to fire.
In learning what we can from the collapse of the Towers, we also need to pay significant attention to the fire protection measures used to prevent the spread of fire and to protect steel structures from excessive heat.
Do we require enough of these measures? Do we know if fire-resistant coatings and blockers remain in place year after year? Why is it I have personally seen protective coatings that have crumbled off steel girders?
In the early morning hours of Sunday, June 9th of this year in Lexington, Illinois, a fire erupted in the local high school, causing serious structural damage to the building. Heat from the blaze was so intense that aluminum columns melted, steel support beams buckled.
Could more have been done to protect the structure of this building? Have we looked for answers in other tall buildings that were constructed about the same time as the World Trade Center? Or do we honestly think we will get more answers from the rubble that was culled from Ground Zero?
Have we taken a close enough look at the fire inspection reports for the Twin Towers, and who wrote them? This sort of activity is supervised in New Jersey by the director of the division of fire safety. State Fire Administrator James Burns has the same responsibility in New York State. The New York City Fire Department has one of the most expert inspection teams in the nation.
None of these government agencies has the authority to inspect these buildings.
The Port Authority has its government with its own rules, including the sole authority to conduct fire prevention and building code enforcement in its own structures.
We have been told that the strength of systems failed, but do we know from official records that there were sprinklers throughout the two towers? I know that I do not have the answer to that question.
Is anyone asking how many government agencies exempt themselves from fire safety standards? I'm asking questions that may be unpopular and possibly beyond the scope of your input. Therefore, our association will conduct its own inquiry into the questions I've asked and others that certainly will arise.
We will do so with the cooperation of building owners, architects, materials producers, standards experts and fire officials who share our concern, and who share our determination that the buildings we live, work and learn in are as safe as is reasonably possible.
And we will look not just at tall buildings, but at all commercial, industrial and institutional occupancies. We will begin in a matter of a few weeks.
The results of our work will be shared with the public. Where necessary, we will point to specific failings in the building codes and in enforcement practices.
We have no interest in assigning blame, but an absolute and abiding interest in getting it right.
Thank you very much.
Conference Facilitator: Thank you, George.
(APPLAUSE)
Our next speaker is Frank Lombardi of the Port Authority of New York and New Jersey.
Frank Lombardi, Port Authority of New York and New Jersey: Thank you, and good morning.
Port Authority staff suffered terribly on September 11th. The proud family of public employees lost 75 of its own, 37 of which were police officers and commanders, 38 civilian employees, and an additional nine contract employees in the attacks on the World Trade Center.
Despite the overwhelming grief felt by PA staff, they literally dusted themselves off that day and went right back to work.
Through their remarkable efforts in the days and weeks that followed, they proved - provided calm in a time of chaos, and security in a time of uncertainty, helping with rescue and recovery efforts and keeping vital public transportation facilities open and safe.
Today, New York City and the region face perhaps the biggest and more complex rebuilding project in the region's history. The Port Authority will work closely with a number of agencies, including the Lower Manhattan Development Corporation, the MTA, the New York State and City departments of transportation, and New Jersey Transit to build a consensus on the best redevelopment and transportation plan.
I am confident that with the input and cooperation of all these organizations and of many public-spirited citizens, we will emerge from this difficult period with a revitalized downtown Manhattan and a magnificent memorial to the innocent victims of the attacks that also pays tribute to the sacrifice and bravery of the rescuers.
I am here to express support of NIST's pending investigation of the World Trade buildings' collapse on September 11th, 2001.
On January of this year, some of our key staff attended a meeting with Dr. Shyam Sunder, Chief of the Structures Division at NIST, along with representatives from other local agencies in New York City. During this meeting, Dr. Sunder briefed us on NIST, its Building and Fire Research Laboratory, and the comprehensive public/private program planned in response to the events of September 11th, 2001.
He also shared with us the plans for the technical investigation, including the use of an independent technical review panel composed of leading practitioners and academic experts to guide the investigation.
The Port Authority has a history of cooperation with and participation in similar investigations. The Port Authority has supported and cooperated with ASCE/FEMA building performance and assessment team in their successful investigation of the World Trade Center investigation.
After the first World Trade Center terrorist attack in 1993, the Port Authority and the New York City Department of Buildings entered into a memorandum of understanding that established procedures for the purpose of assuring that construction projects undertaken at buildings owned or operated by the Port Authority in New York City conform with the standards set forth in the New York City Building Code.
This memorandum of understanding reaffirmed the longstanding policy of the Port Authority to meet or exceed local building codes and fire codes of the municipality in which it owns and operates facilities.
Going forward, the Port Authority has an enormous and critically important construction agenda, not just for the World Trade Center site, but for the New York-New Jersey region as a whole, a program rebuilding and reinvestment in the region's transportation infrastructure.
One of our key objectives is to build a new comprehensive, integrated transportation hub in the vicinity of the World Trade Center site that will be a catalyst for future development. The components of the transportation hub that will serve the site include a new PATH station, a grand downtown terminal, mass transit connections and underground concourses.
Our rebuilding plans must serve needs of the millions of visitors who will pay their respects there, the needs of the community - the commuters, the needs of the residents and the needs of the business who will depend upon this transportation hub to transport their employees and customers.
Safety, as always, is our paramount concern. We must learn from the past in order to plan for what will come. We are hopeful that the outcome of this current investigation will yield insights that will help both the government and private sector improve upon existing building and fire safety standards.
I believe that NIST is the appropriate federal agency to conduct this investigation. The Port Authority of New York and New Jersey will cooperate with NIST in this effort and will participate to the extent that we are able. I believe that the findings and recommendations of this work will be extremely valuable to the building and fire safety communities and to the future safety and well being of the American public.
Thank you and have a good day.
Conference Facilitator: As a reminder, we're going to hold all applause until the end. We want to get all our speakers through.
I also want to commend all the speakers for being on time. Everything's working out very well.
Our next speaker is James Quintiere.
James Quintiere: Good morning.
I'm listed as speaking for myself, but I'm a professor at the University of Maryland in the Department of Fire Protection Engineering. Even those of us in the Department debate issues like this, and as we debate them, I feel we can get closer to the path of truth, though that debate has to be a technical one.
Being in the University, we have a lot of freedom, so I do speak for myself today, and I want to make that perfectly clear. Let me get to my comments.
I would like to commend NIST, particularly the Building Fire and Research Lab, for their persistence at obtaining federal government authority to conduct the forensic investigation of the collapse of the World Trade Center buildings. On the other hand, I would like to condemn the federal and local governments for not initiating an immediate investigation of the building fire-induced collapses. As a consequence, evidence has been lost and information muddied. Although NIST has taken a step forward, I still see one hand tied.
The NIST objectives are generally proper but need to be streamlined, in my opinion. Only objectives one and three deal directly with the collapse issues. Why did these buildings fall and what does that mean for fire safety? Those are the key questions that need to be answered. All else follows from those answers. The other issues of evacuation, first response, and firefighting technology are somewhat ancillary and should be the subjects of future research.
The NIST plan is a dilution of what I believe should be the primary objective - the collapse. The tasks appear to further dilute, however, clear levels of effort in terms of funding and staff to these tasks might clarify their priorities. I would suggest that they bring more focus, definition, and timing to their tasks. The order of their approach, I believe, is critical. They cannot allow these tasks to progress in parallel. The timing and relationship of the tasks is not clear in the plan. I suggest that the order of their plan consider the process that I will outline.
Essentially, number one - there should be a collection and analysis of data. This should include very specifically the World Trade design and maintenance records. This was stated as part of the plan, but I'm stating again this is what I feel should be emphasized and brought to a focus, not diluted by other studies.
Occupant accounts should be gathered on the fire and damage that was seen. For example, "The New York Times" wrote an article on May 26 that outlined very dramatically what was going on in the buildings in the words of those that survived and those that did not. And that type of information is essential in trying to understand what this building was like in fire (ph), and that is not going to be predicted from a computer code.
Videos and photographs need to be reviewed. This is a very intensive effort that needs to be undertaken. And I might point out that many times, there is an allusion to a New York Police helicopter that had videos, and I don't think anyone in this investigative effort has been privy to those yet.
So, therefore, I say tasks one and seven should be modified in the plan to focus on these issues, and they should feed into the other analyses. Task three on the steel should be (inaudible) at this time initially, and tasks one, seven, and eight should be revised or eliminated as they now stand.
The second step should be baseline and structural damage from the aircraft. This is scheduled to be done by task two. The approach side - it appears to rely on computer modeling, and this should have an expectation on the accuracy and reliability of this approach based on the state of the art. That is not stated in the plan, so in other words, how reliable is the approach taken here. I urge alternative consideration. People have used physical scale modeling in trying to simulate collision aspects between objects, particularly in the transportation field.
Thirdly, once this information is laid out - once you have information about what was going on inside the building, what kind of damage took place, what was the initial damage from the aircraft, then you can effectively deal with the fire. Those have to be inputs to any model or any experiment. This is stated to be done in task five.
The task acknowledges the need for fire load data. I encourage NIST to measure the firepower furnishings, not simply rely on fire loading data. They have the ability to do that with their large-scale testing facility.
The method of calculation in this task appears to be the Building Fire Research CFD model, which is called the Fire Dynamic Simulation model. This code is still weak in predicting the fire region, which is crucial in this analysis. Therefore, I urge NIST not to do scale-model testing to validate the FDS model, but to conduct similitude scale modeling to complement FDS. What that basically means is people design aircraft using wind tunnel analysis. They also do computer modeling - the computer prominent modelings that’s come later. When you do fire analysis, you can use both steps. Computer simulation is more attractive today. Scale modeling still works.
Finally, you relate to the structure and collapse, and they need the fire input. Anyone who's going to analyze the structure is going to need to know the temperature conditions at every point in that structure. This task is most important for resolving - for resolving all of the theories that have been presented on the collapse.
Finally, I offer one hypothesis on the root cause of the collapse of the World Trade Towers, Number One - the North, and Number Two, the South. The FEMA ASCE report lists the insulation thickness as three-quarters of inch in the South Tower and one-and-a-half inches in the North Tower. The respective collapse times after impact are approximately 56 and 104 minutes respectively - 56 related to three-quarters of an inch, 104 to an inch-and-a-half. One does not have to be an expert to see the correlation.
Therefore, we have done calculations for these amounts of insulation on the 1.09-inch diameter truss chords. The results of these calculation show the truss chords will fail in times that match the actual failure times within the level of accuracy that we presently have.
These results prompt several questions. Why was the Port Authority changing the insulation from three-quarters of an inch to an inch-and-a-half? What was the basis for the insulation requirement in the initial design? The insulation used is too little, according to our calculations. We feel this is a critical area for more study, and urge a full resolution of this issue since it bears on the safety of existing buildings.
Thank you very much for this opportunity to publicly address these issues.
Conference Facilitator: Thank you, James.
Our next speaker is Abolhassan Astaneh-Asl.
Abolhassan Astaneh-Asl, University of California at Berkeley:
My name is Abolhassan Astaneh-Asl. I'm at UC Berkeley but I make my comments here today on my own behalf and do not represent any agency or individual. I have had no financial or other interaction with NIST in the past nor do I have any at the present.
My work on the World Trade Center is dedicated to the memories of all victims of the 9/11 terrorist attacks, including the firefighters, police officers, emergency response personnel and other responders who so heroically sacrificed their lives to save others.
First I would like to very briefly give you a summary of what we have been doing as far as the investigation of the World Trade Center, funded by the National Science Foundation. I started my field investigation of the structural aspects of the World Trade Center collapse in New York City one week after the 9/11 tragedy. I investigated the structural remains of the World Trade Center towers and building 7 and I have collected data on quality of construction, failure modes, as well as fire and impact damage. I have also identified and saved some key elements of the World Trade Center that appear to have been impacted by the planes or have been exposed to intense fire.
We plan to finish our studies by September and we will turn over all information, all the data involved, published or unpublished, to NIST.
Since April, after receiving drawing thanks to FEMA and going through Port Authority of New York and New Jersey we have been able and busy in building a realistic model of the World Trade Center structure to subject it to the impact of airplanes and ensuring fire. This is the initial model, which does not represent the World Trade Center.
What I want to show you is an analysis of the events so far using the actual drawings of the World Trade Center.
This is the top ten floors of the impact area of the North tower and what we have done is we have modeled airplanes. This is the impact of the 767. This is a scaled-down version of the 747 that we have, the information on, but the model of the building is realistic.
Now, what you're going to see is basically the airplane, three seconds of action, the airplane hitting the building, going in about 30 feet -- until it hits the building and 30 feet penetrated inside the building. That's how far we have gone so far.
This is basically the stresses and you can see that the red indicates fractures so we have established that, in fact, this plane, which somehow represents a 767 but not exactly, indeed penetrates the outside walls and now we are working on getting the plane to hit the inside.
This shows what we have been doing. I have to mention that this study is perhaps less than 1 percent of what is proposed to be done by NIST, so it should not give you any impression that really this is in any way going to do what will the enormous amount of information that will come out of NIST.
We hope simulating what happened on 9/11 will include the main systems in the analysis model and we will be able to look into what will happen if you have more robust systems. These are systems that we have developed at UC Berkeley for seismic and blast systems. Basically, this is a wall for around the stairwell, which consists of steel plates welded to the columns and beams, then concrete walls four inches to six inches thick are bolted to it. And this is a test of two stories of that system and we believe such systems can be used and I hope I'm sure, as far as I've been able to identify from the plans, NIST is going to look at all of this and hopefully there will be more developments in the future for better technology to protect our structures.
My comments on NIST’s proposed plan is I strongly believe we need a comprehensive investigation of the World Trade Center collapse. The proposed NIST plan, in my opinion, is a sound plan and what is needed to be done. And this plan can provide data on what changes are needed in structural design codes, construction and fireproofing methods, as well as firefighting, evacuation and rescue procedures.
I have a suggestion: Although this is basically a good plan, so it is not anything that I'd like to add to the plan, but I'd like to emphasize that the expertise of academic researchers should be tapped to its full extent in the plan. It's already done but I hope with emphasis on it the involvement of faculty researchers not only brings truly independent and highly qualified expertise to bear on this problem but it also helps to educate students, whom upon graduation as scientists and engineers can apply the technology and continue disseminating the information generated in this project.
Concluding remarks: Since 9/11 there has been a criticism of possible loss of data due to recycling the World Trade Center steel and lack of researchers' access to ground zero. I have done such constructive criticism and the Skyscraper Safety Campaign has done a great job.
At this point it is my belief that thanks to the efforts of many faculty researchers and FEMA, as well as the SEAONY engineers, Structural Engineering Association of New York, they have the necessary data and materials to embark on this very important investigation.
We need to put everything behind. All those people, the city of New York, Port Authority, they did their best to search and rescue and then to recover 3,000 loved ones that were in that site. The last thing in their minds was and should have been of course, the first thing should have been the survival of those people.
Finally, I would like to call on all sectors of the engineering and scientific community to support and participate fully in this very important and sound effort. I also would like to call on the public to support the efforts of the Committee on Science of the House of Representatives, which under the leadership of Chairman Boehlert and certainly with very much the efforts of the Honorable Congressman Weiner of New York, not only have initiated this investigation but have introduced legislation to designate NIST as the lead agency for such investigations in the future.
Only with efforts such as the pending NIST plan will result in improving our design, construction, firefighting and rescue efforts, we can truly pay tribute to those who perished in the events of September 11th as well as prevent such tragedies in the future. It will be a true monument to the memory of those who perished from scientific and engineering communities. Thank you very much.
Conference Facilitator: Thank you, Abolhassan. Our next speaker is Ray Daddazio, Weidingler Associates.
Ray Daddazio, Weidlinger Associates: Thank you very much. Dr. Sunder, Dr. Snell, thank you for the opportunity to comment on NIST’s planned investigation into the World Trade Center disaster. NIST deserves to be commended for the substantial effort that went into generating a well thought out plan. NIST’s plan seek to build, in part, on the BPAT report, supplementing it with the rigor that was not possible given the urgent need to make some sense out of what happened last September 11th.
I represent Weidlinger Associates, a structural engineering consulting firm that has been practicing in New York City for over 50 years. Our area of expertise is in the design and analysis of structures, and my remarks today will primarily focus on the areas of the NIST plan that relate to these areas. Namely, project number two, baseline structural performance, and aircraft impact damage. Much of our firm’s work for the Department of Defense over the last decade involved many of the key elements of the attack on the twin towers by commercial aircraft.
We are hear today to communicate the lessons that we have learned, with the hope that those who execute the NIST plan will benefit. Since 1992, we have worked with the Department of Defense on weapons systems safety assessments where we have studied a wide range of military transport vehicles impacting maintenance facilities and aircraft shelters. In many cases, tests were conducted, which helped us to develop and refine advanced modeling techniques.
We see the challenges in NIST’s aircraft impact damage prediction tasks as follows. There is a need to describe the failure and post failure of responses (ph) to materials involved, the steel and the concrete. This is complicated in the case of the World Trade Center because several strengths of steel were used to construct the towers. There will necessarily be uncertainties in the properties of the materials, particularly under high rates of loading, and elevated temperatures. The coupling of gravity, and the high rates of loading, makes scale model testing approximate.
Therefore, project number three, the forensic analysis of the structural steel will provide critical information for the damage assessment of the towers to the aircraft impact. There are uncertainties in the structure with respect to construction details and connection response. There are uncertainties with respect to the airplane, specifically, it’s weight, speed, angle of attack, and fuel quantity. Understanding the inherent uncertainties is a critical issue.
Even though NIST will be bringing state of the art computer simulations to bear, some key items can never be well known. An important point to remember here is that these high-end computational tools will provide a range of possible physics based answers to what actually happened. But I’d like to show a couple of examples of the type of work that has been done that perhaps can give some assurance that the modeling and simulation techniques that NIST hopes to bring to bear on this project have some foundation. And it’s directly related to the understanding of the World Trade Center Disaster. With modeling and airplane impact scenarios, the fuselage of the aircraft, the wings, and the engines all must be considered. Here we see a test with an aircraft engine impacting into a reinforced concrete wall.
This is the same event that – slowed down greatly. Now, we see a first principals, physics-based simulation of the same test. Aircraft engines are massive and stiff systems that will cause major damage to any structure on impact. Proper modeling of the engine is critical to predicting and understanding the damage of the structure. Another test shown on this slide was conducted to develop the dynamic characteristics of an aircraft’s fuselage. In this test, the fuselage of a military transport was dropped, and a section was instrumented, and that data and others like it serve to provide that necessary test data to develop computer modeling approaches for aircrafts.
Next we see the basis for computer models of a military transport. Note the attention to the detail in the representation of the aircraft. We have found that capturing this detail is critical to determining the response of the structure hit by the aircraft. Here we see a computational model of the entire aircraft. In utilizing these models, and here we see a simulation of an aircraft impacting into a reinforced concrete building.
In this animation, note that both the plane and the building are severely damaged. The interaction of the damage between the aircraft and the structure is critical to determining the understanding of the damage to the structure. Here’s another view of the same thing. Finally, this is a picture of the interim damage state of the structure with the airplane removed. I want you to see the damage to the slab and the columns and this building would ultimately fall down.
Defense computational techniques have been validated and used to understand the response of fluid filled tanks subjected to bomb blasts. Similar approaches can be used to help understand the rupture of the fuel tanks and fuel dispersal, giving key information about the early time fire. Finally, with respect to the progressive collapse of the structure, the critical items are in the understanding of the degradation of the supports and the joint modeling. This will need to be addressed in the NIST investigation.
In concluding, I would like to thank you all for your time. In our opinion, the plan that NIST has presented is well thought out, and I am sure that the comments today will help to make it even more comprehensive. One of the hallmarks of this disaster, of the cleanup, the BPAT study, is how disparate individuals and groups have come together to get their jobs done. This same cooperation will have to continue in order for the NIST investigation to realize it’s full potential. I would submit that we owe such cooperation to ourselves and to our children. Thank you.
Conference Facilitator: Thank you, Ray. That concludes the first public session. A few quick notes. First I want to commend the speakers for staying with on time and on topic. I want to mention to the next group of speakers that we need you to report to the front of the room and bring any audiovisual devices to us now so we can set them up for the next session, which will start in 15 minutes. One more reminder for the audience: You are going to be checked once again when you come back in the room. If you bring a bag outside of the room, it will be once again checked, so you may leave your bag in the room and avoid that. That’s up to you. Thank you very much, our next session will start at 10:15.