JAMES
THE MYSTERY OF THE SOUTH TOWER
Tue Nov 26 14:33:13 2002
208.152.73.196

THE MYSTERY OF THE SOUTH TOWER
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A SHEAF OF STEEL SPIRES RISING HIGH INTO THE SKY
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HE SENT THE FORENSIC EVIDENCE TO SOUTH KOREA


The mystery of the South Tower. There should have been a sheaf of steel spires rising high into the sky. But there wasn't. The second airplane came in at an angle, very high, and struck the corner of the building; so most of the burning jet fuel escaped in a fiery glow that spread into the air.

The greater part of the building's support came from the center massive steel rectangular columns, over forty of them, all of them close enough together to form what would be thought of as a sheaf, each and every steel column perhaps two feet, 60 cm, or more wide. At every few floors, they were joined together, perhaps in a staggered fashion. The temperature of burning jet fuel has been estimated at 350 degrees Centigrade, but steel melts at considerably higher temperatures, 550 degrees Centigrade, or more.

All of this means that only a small part of the jet fuel was available to burn, and at lower than necessary temperatures, and relatively far away from the massive steel columns in the center. So, if the floors came down in a pancake fashion, an explanation that has been offered, there should have been something left.

There should have been a sheaf of massive steel spires rising high into the sky. But there wasn't.

There should have been forensic investigations of the massive steel columns, some clearly protruding from the debris. But there weren't. The FEMA wouldn't let the New York City Fire Department do them.

All of the debris in the Plaza was removed, across New York Harbor, to Staten Island. It took four or more months to do this. All except the massive steel columns. These were removed by a special company, and the work was done very quickly, in just a matter of days. This was a company, selected by FEMA (Bush), that usually does controlled implosions of unwanted office buildings. They even found the steel column portions of the debris where they would usually expect to find this, in the Plaza itself, instead of debris being spread all over the western part of the Battery. Moreover, this company didn't transport the steel columns to Staten Island. Instead, they quickly transported all of the steel columns to a far away place, usually South Korea.

How can things like this happen? At this point, some might be tempted to say, the way they used to say about the Reichstag, about people such as Hitler, let Bush be Bush. At this point, some might also be tempted to say, some United States Congress. Some investigation. And where were the American media? Talking to each other again, about the same boring things again, and merely pretending to talk to the American people?

And why South Korea? South Korea is a semi-autocratic, formerly third-world country, facing attack from North Korea, so they can therefore be expected to be accommodating to a demand like this from the Bush family. South Korea is one of the very few countries that has a large steel industry, with very large blast furnaces that can reach the extraordinarily high temperatures required to melt finished steel, and thereby melt away the forensic evidence. South Korea is sure a long, long way from Staten Island.

The Bush family might then whine that they quickly sent it to South Korea because it was "economically" prudent. After all, steel is more expensive than plain, old concrete debris. And it was the steel that held the building up. And it was the shattered steel that brought the building down.

With this type of lame explanation from the Bush family, the response ought to be, "Never mind the economics, Bush. Where's the forensic evidence?"


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The Tube
The final design for the WTC was a group effort, bringing together the work of dozens of architects, structural engineers and managers, led by a few prominent talents. The Port Authority's Guy Tozzoli selected the final team and managed the entire design and construction process; the chief architect on the project, Minoru Yamasaki, came up with the the twin towers concept, as well as the basic layout for the rest of the complex; structural engineers Leslie Robertson and John Skilling figured out how to make the towers stand up.

The final complex consisted of seven buildings, dominated by the twin 110-story towers rising more than 1,360 feet (415 meters) above an open plaza. The monumental tower design was innovative, ambitious and deceptively simple.

At the time of construction, most new skyscrapers were built around grid-style steel skeletons. In this design, the support structure is spread throughout the entire building. Metal beams are riveted end to end to form vertical columns, and at each floor level, these vertical columns are connected to horizontal girder beams. The support columns are all internal, so the outside of the building doesn't have to hold up anything but its own weight. These outer curtain walls can be made of just about anything, including ordinary glass.

The WTC team took a slightly different approach. They decided to build long "tubes," where all the support columns would be around the outside of the building and at the central core of the building. Essentially, each tower was a box within a box, joined by horizontal trusses at each floor.

The outer box, measuring 208 feet by 208 feet (63x63 m), was made up of 14-inch (36-cm) wide steel columns, 59 per building face, spaced just over 3 feet (1 m) apart. On every floor above the plaza level, the spaces between the columns housed 22-inch (56-cm) windows. Yamasaki, who had a pronounced fear of heights, felt that the small windows made the building feel more secure. The columns were covered with aluminum, giving the towers a distinctive silver color. The inner box at the core of each tower measured about 135 feet by 85 feet (41x26 m). Its 47 heavy steel columns surrounded a large open area housing elevators, stairwells and restrooms.


THE TUBE
The World Trade Center towers had an innovative "tube" design, with a perimeter support structure joined to a central core structure with horizontal floor trusses.


This design had two major advantages. First of all, it gave the building remarkable stability. In addition to shouldering some of the vertical load (the weight of the building), the outer steel columns supported all of the horizontal forces acting on the tower (the force of the wind). This meant the inner support structure was completely dedicated to the huge vertical loads.

Secondly, the tube design made for great real estate. With the support structure moved to the sides and center of the building, there was no need to space bulky columns throughout each floor. Clients could configure the available space, about 3/4 of an acre per floor, however they wanted.

The vertical support columns at the core of the building went all the way down below the bottom floor, through the basement structure, to the spread footing structure below ground. In the spread footing design, each support column rests directly on a cast-iron plate, which sits on top of a grillage. The grillage is basically a stack of horizontal steel beams, lined side by side in two or more layers (see diagram below). The grillage rests on a thick concrete pad poured on the solid bedrock deep underground. This pyramid shape distributes the concentrated weight from the columns over a wide, solid surface. With the steel in place, the entire structure was covered with concrete.



Near the base of each tower, at the plaza level, the narrowly spaced perimeter support columns rested on "column trees." The arched column trees spread the weight from the narrowly spaced columns over thicker columns spaced about 10 feet (3 m) apart. Each of these columns rested on additional, smaller support footings in the foundation.

New Shape
In addition to utilizing an unconventional structural design, the Twin Towers were also an aesthetic departure from the older buildings in New York. Most of the city's skyscrapers have a "wedding cake" shape, with larger sections on the bottom tapering off into smaller sections on top. This was partly due to the prevailing architectural style in the first half of the 20th century, but it was also a result of New York's zoning restrictions. In order to ensure that walls of skyscrapers didn't block all light from reaching the street, the city passed a resolution in 1916 dictating that all skyscrapers would have an overall pyramid shape.

A new resolution in 1962 shifted the focus, regulating overall height rather than shape. The new restrictions dictated a maximum number of floors, based on the district of the building and the total area of the plot. The Port Authority was allowed to build such tall towers because they had a huge plot of land with a large, open-area plaza. (Check out this site for more information.)