Use of stainless steel and zero-stress design℠
John Mclean, RA, Architect and Industrial Designer, presented his revolutionary vision for a new architecture to the SSINA members at its Market Development Meeting in Alexandria, Washington, DC, on 10 April 2003.
Mclean’s approach to design uses stainless steel exclusively as the building material of choice. More specifically, stainless steel and water are the principal structural materials, and the basis for his concept of zero-stress design℠. Architectural drawings and models expressed his vision for this revolutionary architectural approach that uses stainless steel to produce an elegant, stronger, lighter and safer building. An additional benefit of the stainless steel zero-stress structure℠ is that the structural elements form the finished face of the entire structure.
Mclean demonstrated the strength of a structure using zero-stress design℠, with a unique test model, and then proceeded to analyze the individual components of the structural model he was proposing.
This new type of building results in a higher strength capacity, than can be realized with carbon steel. Zero-stress design℠, eliminates compressive stress, with the result that the maximum structural strength of stainless steel is always tapped.
The unique characteristics of zero-stress design℠ are:
A stronger and lighter structure that uses
A simple system using water-filled tubes lends itself
by John Mclean, RA
A building’s weight is tremendous. Often the heaviest parts do nothing structurally. This is inefficient. If the ratio could be reversed, structural efficiency would be greatly improved. A large building weight is indicative not only of massiveness but of redundant construction. Many types of exterior enclosures or “skins” are as strong as the structure supporting them, and may weigh more. Claddings should be tapped structurally.
If the industrialization of building aims to make construction more affordable, then it means, in addition to mass production methods, the further development of lighter and stronger structures, new materials technology and the integration of building components. Useful materials must be evaluated for their architectural potential. Ways of using glass and plastic materials structurally should be found. Conventional construction materials should be made able to perform at a higher level.
The zero-stress℠ structural system, a design research project proposed here, is intended to reduce the cost of building. The reductions would come from the system’s high structural strength and efficiency, and its receptiveness for integrating building components into the structural system itself.
A zero-stress℠ structure is light. A zero compressive state maximizes the strength of the material used, so that the structure can be considerably less massive.
Zero-stressing℠ extends architectural and spatial concepts. Unlike many structural systems, zero-stress is not based on a special geometric configuration and is therefore widely applicable. The design proposals illustrated are spatially tensile and vibrant.
Zero-stressing℠ may allow us to use materials such as plastics and reinforced or structural glass for structural purposes. Plastic materials have been developed with strength—but not stiffness—approaching that of steel. Consequently, plastic columns and beams have had extremely limited uses. Nevertheless, the structural possibilities of plastics, glass, steel, nickel-stainless steel and reinforced concrete are tremendously extended by zero-stressing℠. A possible spin-off of the zero-stress technology℠ is the further strengthening of materials such as steel. We increase the strength of glass fourfold by tempering it. In a similar manner, by highly pressurizing molten steel and allowing it to cool in a columnar form, there may result a column with greatly extended strength.
Some of the design potentials of zero-stressing can be seen in the illustrated concepts. One is the continuous tension bridge of multiple three-mile spans with zero-compression support towers. The second is the Horizontal Skyscraper℠. The system can also be applied to smaller projects such as a single-family house.
A year had past and the September 8, 2002, Sunday New York Times Magazine arrived and was devoted to the World Trade Center and the site. The critical article was "Towering Ambition", later retitled as "Height of Ambition". I found I had to read the article three times to confirm what I was reading.
What follows is my letter-to-the-editor, not published by the Times, that was widely distributed within the architectural and engineering community and personally sent to Leslie E. Robertson, PE, the structural engineer for the twin towers.
30 October, 2002
Article: “Towering Ambition”, The New York Times Magazine, by James Glanz and Eric Lipton,
Sunday, September 8, 2002, section 6
To the Editor:
James Glanz and Eric Lipton have presented a detailed history of the conception and construction of the World Trade Center Towers. As much as I wanted to read about the business of acquiring the site and the building of the Towers, I was taken aback by the underlying message that the collapse of the Towers was a collapse waiting to happen due to ambition and that the September 11th act of war was the straw that broke the camel’s back. So I ask, what part of W-A-R did the authors not understand? The WAGING of war? The ARTILLERY of war? Or the RATIONALIZATIONS for war?
As for the WAGING, the terrorist had one purpose in mind. They wanted to demolish The World Trade Center Towers because they were more than a symbol of the strength of the United States. The Towers had become a metaphor for the nation’s strength when the terrorists failed to topple it in February of 1993. In each instance, they were attacked with the purpose of demolishing them, regardless of the fact that the people were in the building and would be killed. The first was a failed attacked; the second accomplished its heinous act of inhumanity.
As for the ARTILLERY of war, they used two fully fueled jet airplanes. The jet planes were the means to deliver the highly incendiary source of heat energy, namely jet fuel. Buildings are designed for fire safety on the basis that a source of ignition would ignite material in a space that in turn kindles a fire, such as one in a fireplace. Buildings are not designed to resist bombs, incendiary devices and artillery, but are designed to resist fire for a specified time period. Structural steel is required by building laws to be protected by fire resistive coverings that have hourly ratings. A three-hour rating resists the fire by restricting the rise in temperature of the steel (or the wall construction) not to exceed 200° F after three hours. On September 11th, the jet incinerated at 2000° F. At such high temperatures and energy levels, even concrete, which is composed of cementitious compounds and the water of hydration, will start to breakdown and release steam. In essence, no protective covering is afforded.
Are skyscrapers designed not to topple because of the impact of an airplane? The answer is basically yes. This is true because the storm wind forces are so much greater than that of the impact of an airplane or of seismic activities. The Trade Center Towers did not topple because of the airplanes crashing into them. Yet there was no reporting in the article on what procedures are followed by pilots for a crash landing? Normally the air speed is reduced to the minimum, the fuel is discharged before crashing, and the engines are shut down as soon as possible in order to prevent incineration of everyone. Just the opposite was done by the terrorist who took control of the jets on September 11th.
Basic logic and balancing the viewpoint is lacking in the article. The authors failed to ask Architects and Structural Engineers, “Are buildings designed to withstand the ravages of war?” If the answer is or should be yes, then the buildings we must design are mountain-like masses with habitable cave pockets within. Once a war-proof building is built, it is then by definition almost impossible to renovate or demolish. The energy needed to change such a structure may harm or destroy the neighborhood.
The so called secrecy the authors present as a clandestine attempt to conceal the sway of the Towers is nothing more than a scientific precaution to ensure a reasonable measure of the perception of movement of the testing room. Incidentally, the Empire State Building sways a considerable amount at the top, and is not rigid in the sense of not swaying. The structural flexibility is essential in order to properly dampened stresses. Architect Yamasaki and Structural Engineer Robertson rightly performed the test, just as a scientist does when testing new drugs (that is, the tested subjects do not know if they are getting the drug or a placebo). The eye test was the placebo.
The authors, who are apparently not structural engineers, implicitly report that Robertson used insufficiently sized steel that was ¼” thick in the columns at the top of the Towers. No where in the article did they report that the steel thickness is calculated to be in excess of that required to resist actual anticipated forces. That is the premises behind the practice of applying the required “factor of safety”.
Did your authors interview demolitionists? I am sure they would have told them that what the terrorists had done is exactly how they would have taken the buildings down. Namely, weaken a higher floor with incendiaries in order to release the high potential energy of the top of the Towers and start a domino effect downward by the kinetic energy released as each floor collapsed onto the one below and so on.
As for the RATIONALIZATIONS for war, your authors should have focused their innuendoes on the ones who performed such an act of war of terror, and then on those whose job it is to monitor the terrorist. Presenting David Rockefeller, Austin Tobin and Guy Tozzoli as ambitious conspirators who did not care about the safety of the World Trade Center Towers is not believable. Your writers give these men more power then they actually possess.
The use of innuendo coupled with the authors’ inability to delve into the complex nature of architectural (and therefore structural) design and professional practice and at the same time satisfying the client’s expectations is inexcusable. The authors have shown insensitivity to those who have lost loved ones in the World Trade Center Towers as a result of the September 11th attack on the United States by terrorists.
The innovations that Yamasaki and Robertson incorporated in the Towers indicate a dedication to the safety. There is always room for improvement, but there was no blunder in the design. The authors have created a false impression that truly investigative reporting was accomplished. The fear and misconceptions that the authors have created is unacceptable.
Architect John Mclean
world trade center 9/11/01