After 9-11: An Engineer's Work at the World Trade Center

By Donald Friedman

The tragic events of September 11, 2001, have forever changed the lives of the individuals and families that were directly affected and have changed history for everyone.

Those same events were the beginning of a 24-hour-per-day, 7-day-per-week effort by structural engineers to investigate the condition of the buildings remaining at the World Trade Center site, to work with the rescue and clean-up crews in evaluating the safety of the towering piles of rubble, and to try to explain what happened to the buildings as they collapsed. After 9-11 describes one engineers experiences on site and off as part of that effort.

• Language: English
• Publisher: Xlibris US
• Release date: Aug 9, 2002
• ISBN: 9781469116174

Donald Friedman

Donald Friedman is Director of Preservation at LZA Technology, a division of the Thornton-Tomasetti Group, Inc., and a graduate in Civil Engineering from Rensselaer Polytechnic Institute. Mr. Friedman’s design and management experience includes integrating modern construction into existing buildings with archaic structural systems, building repair and restoration, and investigation of historic building structure. He is a recognized leader in the field of conservation engineering, teaches engineering of historic buildings at Rensselaer, has spoken at numerous conferences, is the author of Historical Building Construction and The Investigation of Buildings, and co-author of Building the Empire State and The Design of Renovations.

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Copyright © 2002 by Donald Friedman.

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15207

Dedication

To those who died on September 11, 2001 and to

those who risked their lives that day in rescue.

Contents

Introduction

Acknowledgments

September 11, 2001

September 12, 2001

September 13, 2001

September 14-21, 2001

September 22-November 11, 2001

November 12, 2001-

December 22, 2001-

December 23, 2001-

January 6, 2002

January 7, 2002 –

February 13, 2002

Introduction

I have never kept a diary. There have been times I wished I had, but when I got to the end of a day and thought about writing an entry, it didn’t work: if nothing much had happened that day, I couldn’t come up with anything to say; if the events of the day had been momentous, I was sure I would remember the details without writing them down.

On the afternoon of September 11, 2001, some four hours after the attacks on New York and Washington and the failed attack that ended in Pennsylvania, I found out that the company I work for, the Thornton-Tomasetti Group, was likely to be hired to help the City of New York with the World Trade Center site. I had already volunteered for such work as had nearly everyone in the company. My immediate co-workers and myself work in the LZA Technology division of TT, which has as its core building investigation and forensic engineering. We knew we would be leading any company effort.

I did not keep a diary during the events described here. It still seemed that I couldn’t possibly forget what had happened and I was generally so exhausted that I had all but given up on activities other than work. I did collect a record of some events, saving various papers and letting my site equipment collect on the floor of my living room.

Inevitably, as time passed, I realized I was forgetting details. A small portion of this narrative was written in December 2001, but most of it dates from February and March 2002. I had come to the conclusion that if I didn’t get it on paper soon, while the process of story-telling would trigger memories of the details, I would never get it all. I have reconstructed dates as best I can from my timesheets, newspapers I saved, and my field notes.

I have tried, to the best of my ability, to represent what I saw and did with as little personal bias as possible. In some places, a description is all that is needed to explain what happened. In other places, my thoughts at the time or facts that I learned later have a substantial effect on the story’s meaning. In the latter case, I have tried to separate my thoughts and hindsight from the facts; my internal debates and anything I learned at a later date are set off [in bracketed italics.]

There are gray areas in this division between fact and thought: the facts given here are told as I knew them at the time, with later corrections given where appropriate. This is solely what I saw, and my story is not the whole story.

Who’s Who

The people at the World Trade Center site were representatives of both government agencies and private companies. I had worked with almost all of the agencies and many of the companies before September 11 and so they have, to me, their own personalities. I’ve given short descriptions below as a guide for those unfamiliar with the world of building design, construction, management, and ownership.

AMEC: A construction management company. Atlantic-Heydt: A scaffolding and rigging sub-contractor. Bovis: A construction management company. American Society of Civil Engineers (ASCE): The professional society for, among others, structural engineers. Bechtel Group: An engineering and construction company specializing in large design-build projects. Consolidated Edison Company (Con Edison): A New York utility company, supplying electricity, natural gas, and steam in Manhattan.

Federal Emergency Management Agency (FEMA): A national agency charged with hazard mitigation, disaster preparedness, and disaster response.

Fire Department of New York (FDNY): Obviously, in charge of fire prevention and fire fighting. Under the rules in place after September 11, the FDNY was in charge of the site, and could request or veto specific items of work to be performed by other agencies (such as DDC) or the various private companies present, including TT.

Leslie E. Robertson Associates (LERA): A structural engineering company. A successor firm to Worthington, Skilling, Helle and Jackson, the original structural engineering designers of the World Trade Center buildings.

Metropolitan Transportation Authority (MTA): A semi-autonomous agency responsible for the bridges and tunnels within New York City, commuter railroads, city buses, and through its Transit Authority division, the New York City subways.

Meuser Rutledge Consulting Engineers: A geotechnical engineering company. The original designers of the World Trade Center foundations.

New York City Department of Buildings (DoB): The agency charged with review of building construction and alteration within the city, including enforcement of the city building code.

New York City Department of Design and Construction (DDC): The agency responsible for overseeing construction projects performed for the city government, serving as the owner for architects, engineers, and contractors working on these projects.

New York City Office of Emergency Management (OEM): The agency responsible for coordinating efforts of all other city agencies and for serving as a liaison with federal and state agencies during major emergencies.

New York City Landmarks Preservation Commission: The city agency responsible for designating buildings as protected landmarks and for review of work proposed on designated buildings.

New York Landmarks Conservancy: A non-profit organization providing advice and funding for projects associated with landmark buildings.

Occupational Safety and Health Administration (OSHA): The agency created by the US Department of Labor to oversee workplace safety.

Port Authority of New York and New Jersey (PA): A bi-state agency responsible for transportation infrastructure in the New York City metropolitan region, including airports, docks, and bridges and tunnels between the two states. The builder, owner, and a tenant in the World Trade Center. The owner and operator of the Port Authority Trans-Hudson railroad (PATH), a subway connecting several cities in New Jersey to lower Manhattan.

Structural Engineers Association of New York (SEAoNY): A professional organization that represents the professional interests of structural engineers in the state.

The Thornton-Tomasetti Group (TT): An engineering company, with a division—LZA Technology—devoted to building investigations and restoration design. My employers.

Turner: A construction management company, working on the WTC site jointly with Plaza Construction.

Tully: A construction management company.

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Acknowledgments

My thanks go to the principals of The Thornton-Tomasetti Group for their attempts to provide decent working conditions in terrible circumstances; to the engineers who, both on site and off, told me stories that filled in a lot of the gaps in my personal experiences, including James Feuerborn, Erleen Hatfield, Aamer Islam, Kyle Krall, Gary Mancini, Gary Panariello, Dave Peraza, Brian Tokarczyk, Dan Eschenazy, Ramon Gilsanz, Rick Mahoney, and Guy Nordenson; and finally to Derek Trelstad for his many suggestions for improvement to a manuscript that I suspect he hadn’t intended to read. The author’s photograph was taken by Adrian Biltoft; all other pictures are the property of the United States Federal Emergency Management Agency and are used by permission.

September 11, 2001

Watching TV

We were about ten minutes into a marketing meeting in the 8th floor conference room when Matthew Holzli opened the door, stuck his head in, and said I don’t mean to interrupt, but the World Trade Center is on fire. [The mood in the room was complete disbelief: Matthew doesn’t have a strange sense of humor.] There was a brief moment of silence and then someone turned on the TV in the conference room while a bunch of us walked over to the east windows facing the setback roof. I climbed through the window by Dave Peraza’s office and walked across the setback so I was at the east handrail facing Sixth Avenue. [Looking south down Sixth has always been a touristy thing, with the WTC blocking the end of the street, so big and yet so obviously far away.] Both towers had large holes facing us, rimmed with flame and with heavy black smoke streaming upwards. I went back inside and watched TV for a few minutes, went to my desk and called my parents and Paula to say I was okay—to say I was in the office and not on a visit to one of my projects downtown—and then tried to reach Mike Hillmeyer, my only friend who works in the World Financial Center. I didn’t get him until I called his home around mid-day.

We had two people in from other offices who were trapped by the travel shut-down. I asked Mark Coggins, from the Philadelphia office, if he had a place to stay. When he said no, I offered my air-mattress if he couldn’t find anything else. I also suggested to Dan Cuoco, the president of LZA Technology, that we try to find beds for people who lived in distant suburbs, just in case. By the early afternoon, as the subways, commuter trains, and highways reopened, it seemed that people would be able to get home so nothing ever came of that idea. Mark stayed with me.

I spent most of the next few hours in the conference room, watching TV. [Sometimes people live up to their stereotypes. I’ve heard stories—from friends, from Paula, from relatives in other cities—about people watching TV in groups, crying, comforting each other, looking at the towers burning and collapsing, and talking about the people trapped inside. What did we do? Stood around in the conference room and tried to figure out the condition of the structures from low-quality video. It’s one thing to crack jokes under pressure—I do it, as do a lot of people I respect—but there’s something wrong when 20 or 25 of us stood there for three hours watching and analyzing building performance before the dead were even dead.]

While watching the TV and talking to various people I did my share of off-the-cuff structural analysis. Most of us thought that the towers would collapse above the break. No one predicted complete failure. No one predicted that the tower floors would pancake. After the south tower collapsed, as the news was showing the video again and again, some thought they saw an explosion. Some thought that the third explosion was the blast effect caused by the pancaking floors pushing out the debris as the debris was created. [Despite our expertise in examining buildings and building failures, the videos became an ink blot in which we each saw our deepest fear of structural failure. The repetition of slow motion video also had the effect of distancing the viewers from the actual event by making it look other-worldly.]

One aspect of the repeated videos that was clear and had implications about the condition of the buildings surrounding the World Trade Center site was the pattern of the dust cloud as the towers collapsed. As first the south tower and then, a little later, the north tower collapsed, there was a dust ghost that remained, almost keeping the shape of the tower. [That would have to be made up of very fine dust particles, and the ghost was in part an artifact of the dry, windless day. I couldn’t look away from those pictures—I was trapped by some combination of fear and a need to analyze what had happened.] Most of the dust came down in an wave that started at the downward-moving location of the collapse (in both cases, watching in slow motion, the collapse seemed to start near the point of the original impact) and spread out. The wave broke over the nearby buildings, looking very much like a wave breaking on the beach. [This was theoretically good news. For the wave to break, the buildings had to be solid. In other words, the dust cloud truly was a dust cloud and not full of large chunks of building that could simply break through other structures. This logic only applied to those buildings that I could see standing with the dust swirling around them—60 Hudson Street, the Travelers, the Woolworth. Since all of the TV angles seemed to be from midtown looking south, I could identify a number of buildings north of the site, but nothing else. It felt good to be able to reason my way to say that there had to be some major buildings in the dust that were structurally sound, but it was obvious that I couldn’t even guess about smaller or closer buildings.]

I became quite angry watching news reports about President Bush being shuttled from Florida to one undisclosed location and then another. A number of people in the office are familiar with my politics and my criticizing Bush was nothing new, but none seemed to get my point until I specifically pointed out that there were some two million people in Manhattan alone, more than twelve million more within a twenty-mile radius, and another three million or so in the Washington, DC, area, all without the ability to fly to an undisclosed location to get away from trouble.

[Is it important for government officials to be safe? Sure. But I hadn’t heard any of them say a word about those of us who were at home when the attacks came, and I didn’t for two more days. I have thought a great deal about my actions and about the meaning of September 11 in terms of what I understand America’s ideals to be. As I had to be at the office early for the marketing meeting and September 11 was a primary election day, I had got up an hour earlier than usual to vote before the meeting. New York City still uses mechanical voting machines, and I was familiar enough with their foibles and the sometimes slow pace of proving registration to allow half an hour for the two-minute process of actually voting. As it turned out, when I got to the polls, halfway between my apartment and the office, I was only the second person from my district to have come in. The results of that poll were thrown out—very few people voted after 9 AM on the 11th. I later voted in the rescheduled primary on my way home from working on site, voted in the primary run-off on a day of sleep following working on site the previous night, and voted in the general election on a normal work day. It’s not often you get to legitimately vote four times in one election.]

A Beautiful Day

As a lot of people have noted, the sky was deep, clear blue. [I heard on the radio weeks later that pilots call it severe clear and, while it doesn’t make much sense in retrospect, I wondered if that had been one of the criteria the hi-jackers used to pick the day. For an amateur pilot, a day with 30 or more miles of visibility must be a good time to fly.] When I was on the roof, the smoke plume from the towers was heading away from me, so the entire visible sky was still that beautiful color except when I looked due south. None of the news reports mentioned how rare such a sky is in New York in the summer: it’s most common in October and November so even though the high was near 80 degrees that day, you could tell fall was coming.

[Over the next few days as that weather held, the high temperatures were a problem, as workers on the site—including us—had a hard time keeping cool and hydrated. The three main concentrations of debris, marking the north and south towers—1 and 2 WTC—and 7 WTC were on fire and would remain so for weeks, adding a lot of heat to the area. Anyone walking near or over the debris generally wished for cooler weather. On the other hand, the clear skies, which became a drought over the course of the fall and winter, facilitated the work. Rain or snow in significant amounts could have created huge difficulties in the work logistics as well as caused more injuries. Partially damaged structures will often collapse in the rain as the water adds weight—the insides of the building getting as wet as the outside—and as exposed, damaged structural elements begin to corrode.]

I left the office around 1 PM to get lunch. When I got back, I heard the news I had been half-expecting. The structural engineers with field experience were all to be ready to go downtown the next day as part of the disaster relief effort. We would get a call at home that night for confirmation and would meet at the office in the morning.

The work we would be performing was typical of structural engineers after a disaster: building evaluation and supporting the physical efforts of contractors (designing shoring as needed and analyzing damaged structures for stability are the two most common items). I had performed similar work before on fire-damaged and neglected buildings, but forensic engineering is not my specialty. My work is almost entirely preservation engineering—providing structural engineering back-up for historic preservation projects—but all that mattered here was that I was an experienced structural engineer familiar with the process of building investigation.

Walking Uptown

Around 2 PM, Mark, Ben Wisniewski, Tom King, and I headed north. Ben and Tom are engineers at TT and both have worked on projects I’d managed. All of us had decided to try giving blood at the Red Cross building on Amsterdam Avenue. Ben and Tom were looking to get home to New Jersey, across the Hudson River, which was complicated by the shut-down of Penn Station and the PATH system and the closing of the vehicular tunnels. I also needed to go uptown to my old apartment. At that time, I was in the process of moving, and even though my furniture was in the new place on 32nd Street, my hard-hat and boots were still up on 103rd Street. With the subways not running it was more than four miles to walk. Mark had decided to come with me, since he didn’t have anywhere else to go until he came to my place to sleep.

We had only made it to 34th Street and Seventh Avenue and were pushing our way through the large crowd trying to get into Penn Station when I heard someone call my name. Diane Kaese was standing there, one of the people heading to Penn Station to go home to New Jersey.

We talked about what we’d seen on TV, our plans (her hopes to get across the Hudson, ours to give blood) and the fact that LZA was going downtown the next day. [Even though her company is one of our main competitors in forensic collapse analysis, she didn’t seem envious of us. I understood the apprehension, but we didn’t talk about it.]

We walked up Seventh Avenue to Times Square, then Broadway to 60th Street, when we cut over to the Red Cross building on Amsterdam. There was little car traffic, although the few cars we saw tended to be driving erratically. As one car went by in Times Square at about 50 miles per hour, Ben made a comment about the speed. My response, which seemed to shock Mark more than the two younger guys who know me better, was Just because there’s a crisis doesn’t make people smarter; doesn’t stop jerks from acting like jerks.

While walking, we heard the sound of jets, loud and moving fast. The first time we couldn’t see the