GT: The original basement construction for the World Trade Center was performed by an Italian company. It was called ICOS and they had a Canadian subsidy/subsidiary, Icanda, that was doing the work at the site. There were a large number of Italian engineers and workers who were working on site. Since I spoke Italian reasonably well and was a staff member of the Port Authority Engineering Department, they asked if I would go down and oversee the construction in a resident engineering capacity. This was back in April of 1967. At the time the work was going very slowly, so we were ramping up to start the work. The slurry wall work was really a very innovative method of constructing the basements. It was probably the only way the basement construction could have been constructed at that location. It was extensive. It was approximately eight city blocks, which was a scale that nobody had done before. It was probably the third project that was done within the United States using this technology. So it was really a very courageous thing that was being done by the Port Authority. Then-Chief Engineer John Kyle was very supportive and enthusiastic about it. Martin Kapp, who was the Chief Foundation Engineer, was also supportive, and there was a big push to use this technology. Ray Monti, who was the manager of the project, invited me down to oversee the work. In one year, we ended up constructing the whole perimeter wall. The tiebacks and the excavation followed subsequent to that.

GT: The wall permitted the construction of what I call the bathtub. It permitted the construction of a watertight perimeter around this four-block site. Within the four-block site there were two operating rail tunnels. The PATH tubes ran transverse across the site into the old Hudson and Manhattan Railroads and they had to be protected during the construction. The foundations of the World Trade Center are really very simple. It's just a building sitting on top of Manhattan bedrock. It was the perimeter wall and the prevention of water from the Hudson River from entering into the site which was really the more difficult part of it. The thing that people don't know is that Henry Hudson landed on the shores of the Hudson River, which is now Greenwich Street, which is the eastern edge of the World Trade Center Bathtub. It was roughly two to three blocks in from the river. The old river line was at Greenwich Street which is the eastern boundary of the World Trade Center. And everything from Greenwich Street to the Hudson River was landfill and very difficult to dig through. There were parts of vessels, piers and all kinds of debris. When buildings would be demolished, the debris was just dumped there, and we encountered all kinds of things. I still have a bottle that was exhumed out of the excavation as sort of a recollection of that particular construction.

GT: There were millions and millions of cubic yards of dirt. I don't remember the volume.

GT: The site was four blocks north south and two blocks east west. That is roughly a thousand feet in the north south direction, roughly five hundred feet in the east west direction. And it's roughly seventy feet deep down to the top of bedrock. The slurry wall itself is only three feet thick. It's really a diaphragm that surrounded this site and it was held back by very high capacity rock anchors. These rock anchors were drilled through the wall, through the soil, and down into the bedrock and socketed into bedrock, to laterally support the wall as the excavation proceeded downward. There was an extensive amount of material that was within the confines of this bathtub that had to be removed. As part of this project, the Port Authority constructed a cellular cofferdam in the Hudson River. It was constructed slightly south of the building site and projected several hundred feet into the river. It was this containment basin that received all the excavated material from the World Trade Center. As the World Trade Center materials were excavated out from within the bathtub, they were trucked across the street and out into what is now Battery Park City. The landfill was the start of the Battery Park City project. And once the landfill was completed, Battery Park City formalized the landfill by building rock dikes and putting good clean sand fill and coming up with a master plan for its development. The World Financial Center, for example, is constructed completely within new ground. The ground that the World Financial Center is sitting on right now did not exist in 1967.

GT: When I walked on the site on the twelfth of September, I was just overwhelmed with the extent of destruction. Something that I had seen and worked on in an earlier stage of my career was absolutely destroyed and pieces of it were just hanging out in space. It was very demoralizing to be very candid with you. The one thing that I think was essential was to approach this as a more technical problem than recognizing that there was the potential for thousands of people to be within this, this graveyard, if you want to call it that. I have kind of set my mind to think of it more as a technical problem: How do we resolve this, how do we secure it, how do we protect the rescuers, how do we eventually exhume all of this structure. How do we deconstruct it and essentially get to the bottom of it to restore the railroad, the subway system, and put something there that would act both as a memorial and as a commercial and transportation center for the city. The site could not remain the way it was. I thought that the only person capable of properly defining the conditions at that site would probably be Dante Alighieri in his definition of hell, because it was really bad.

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