Look Up: That Time a Hurricane Almost Destroyed the Citigroup Center

While this technique seemed sufficient to allow for the corners to remain unobstructed, another problem arose soon after.

In June of 1978, one year after the building was constructed, it was discovered that the building was critically under-engineered. When LeMessurier designed the building, he calculated for only straight and perpendicular wind loads, as these were usually the greatest theoretical loads.

However, an engineering student at Princeton, Joel Weinstein, calculating for a school project, used 45-degree quarter loads and discovered that these were unusually greater. He contacted LeMessurier with his discovery, and at first was assured that the welded construction of the corners would sufficiently withstand these excessive loads as well. It was only later that LeMessurier discovered that to save on costs during construction, the welded joints had been replaced with much weaker bolted ones. 

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