An article published as news in the June 1, 2011, issue of this paper shamelessly mislead readers about the materials used in reconstructing the World Trade Center.
Entitled “One World Trade Center rising on ‘super concrete’” and written by Herbert Margrill, communications vice president for The Concrete Alliance, the lengthy, 2,700-word piece not only lacked the concise, factual tone of a news story, it abandoned reality by extolling “One World Trade Center…as the latest proof of concrete’s superiority,” adding that concrete is the leading choice for building developers.
It is the newspaper’s duty to present accurate information to its readers. On behalf of the Steel Institute of New York, let me correct some of the article’s more blatant misrepresentations.
It must first be said that work at the WTC should be praised, not only as proof of the city’s ability to overcome the terrible events which befell the site a decade ago, but also of the contribution it will make to New York’s infrastructure needs. However, ignoring the predominant role played by structural steel in the reconstruction is not just self-serving, it is a misleading omission.
Told that “210,000 cubic yards of concrete [upwards of 300,000 tons] will be needed to cap the Center’s superstructure,” the reader of the article could hardly be blamed for assuming that concrete is the only material being used in the reconstruction. This massive quantity of material far outstrips the 50,000 tons of steel used for the tower’s beams and columns, no question. But quantity is immaterial.
Steel’s higher strength-to-weight ratio and inherently longer span capabilities always lead to less material-intensive design solutions. More importantly, these qualities will enable One World Trade Center to emerge as 2.6 million square feet of column-free, Class A office space. And they are among the reasons why Larry Silverstein chose steel for towers 2, 3, and 4, why the Durst family chose steel for Bank of America Tower, and why steel was selected by the developers of all but one of the office towers built in the city after 9/11.
Despite its many inaccuracies, the article makes one point that is irrefutable. “The looming threat of climate change … is far more dangerous than terrorism,” Margrill quotes Robert Ledwith, president of the Concrete Alliance, as saying. Adopting a mentality that office towers should be bunker-like designs with concrete stair cores and street level blast walls three feet thick would be a mistake. The city’s goal is to strike a balance between safety and the ability to build affordably during these tough economic times, all without compromising the ability of future generations to meet their own needs.
We must keep in mind the crisis our city will face if we do not keep pace with other nations in providing the finest Class A office space to attract international corporations in our globalized economy. Viewed from this perspective, it would be a mistake to assume—as Ledwith is again quoted as saying—that “concrete is the best choice for the environment.”
A growing amount of research is being published around the globe comparing the relative impacts of structural steel, concrete, and other materials with respect to embodied energy, carbon impacts, and resource depletion. At the same time, the sustainable impacts of various design choices are being compared via a new generation of life cycle analysis estimators.
This research has highlighted the favorable comparative impacts of structural steel versus concrete when viewed from a project-based perspective: More usable space is created with less environmental impact in One World Trade Center using 50,000 tons of steel than with than with 300,000 tons of concrete. This is not to say concrete has no role in the construction. Each material relies on the other in various applications. And just as all building industries are working to keep costs down, all are working to improve their carbon footprint.
The Steel Institute of New York believes strongly that our city’s future cannot be built on a foundation of misinformation. As progress at the World Trade Center site demonstrates, it is imperative that a building embody much more than function. Our city’s structures represent everything we hope for in its future: economic viability, strength, and beauty. Steel’s substantial role in that vision is irrefutable.
Gary Higbee, AIA, is director of industry development, The Steel Institute of New York.