The engineering student who prevented a disaster in the middle of Manhattan
This article goes out for the architects and engineers out there, who sometimes don’t realize how important their work is, but also for everyone else, to point out how doing your best can be enough to make a substantial change in this world. It is about the Citicorp Center Tower building (now called 601 Lexington), which you can distinguish in New York’s skyline, from the triangular shaped top, in the picture above.
In 1978, an undergraduate student in the Civil Engineering and Operations Research Department of Princeton University wrote her thesis, titled, “Implications of a Major Urban Office Complex: The Scientific, Social and Symbolic Meanings of Citicorp Center, New York City”. In her thesis, this initially mysterious student, addressed in detail important safety concerns regarding a skyscraper in Manhattan, the Citicorp Tower. And with a hurricane just waiting around the corner, this skyscraper was on the bridge of collapsing, a disaster just waiting to happen.
Upon the thesis publication, secret work kept far from the publics eye was performed on a two-decade period to make the building safe. So, what’s the story here?
William LeMessurier, a structural engineer, with a great reputation for distinguished works such as Boston Federal Reserve Bank, was offered a consultant position for the project of Citibank corporate headquarters. There was one peculiar challenge to the project: a church owned part of the land where the building was planned to being built, and they didn’t agree to give it up completely. Instead, the bodies reached an agreement: the construction company would rebuild the church structure and in return, the church would give up “air rights”, the construction company could use the space above the church to built the supporting structures for the skyscraper. The sketch below shows the structural situation before the rebuilding. The church is in the side. The new skyscraper would have to be build over the church. Because the church is not in the middle, but rather in the side, the engineering required that the new building would be supported in the central part, rather than in the corners, which represented a major challenge.
LeMessurier designed the building’s framework and column support, so that the weight of the building would redistribute the weight towards the center. This innovative solution saved the need for even normal construction weight and the building was unusual light. Weight had to be added at the top, to make the building safer to wind influence. The building was finished in 1977. As LeMessurier was just a consultant, he wasn’t made aware of one additional decision though: the constructor had decided to use less expensive (and thus, weaker) bolts.
Soon, LeMessurier’s company, would receive a call from a student asking regarding details on the structure. The conversation raised many questions. The student pointed out some inconsistencies. Upon further analyzing the contract’s work, LeMessurier became deeply concerned. It became clear that proper safety measured were not performed and the whole building might have collapsed in an event of a strong enough storm. The hurricane season was approaching. Immediately, action was taken to build additional supporting structures for the skyscraper. Over the next two decades, while the public wasn’t made aware of the reasons, safety measured were continuously performed to assure the building was safe.
The student who initially pointed out the safety issues with Citicorp Tower, is believed to be Diane Hartley, at that time a Princeton Uni student, writing her thesis. Upon stability calculations, she became aware of the shakiness of Citicorp building. When she contacted them, the building designers were trying to hide their mistakes, by not providing their own calculations (even though they reportedly agreed to do so) and by trying to reassure Diana that the building was safe. Her initiative might have prevented a disaster which could risk thousands of lives.
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