EVENT
Citicorp Center Crisis
The 1978 discovery, prompted by an undergraduate student's question, that a completed fifty-nine-story Manhattan skyscraper was vulnerable to catastrophic collapse in a quartering wind — and the quiet midnight remediation that represents the engineering profession's most instructive case of the immune system operating as intended.
The Citicorp Center, designed by William LeMessurier, opened in 1977 in midtown Manhattan. Its unusual architecture placed
the corner columns at the midpoints of each face rather than at the corners, enabling the ground floor to accommodate a church on one corner. In 1978, an undergraduate student at Princeton — later identified as Diane Hartley — asked LeMessurier whether this configuration made the building vulnerable to quartering winds, diagonal winds that would load the structure differently than the perpendicular winds the code typically specified. LeMessurier investigated and discovered that the building was indeed vulnerable. Worse, during construction the welded connections his design specified had been substituted with bolted connections — a cost-saving change that further reduced the structure's capacity. Under a sufficiently strong storm, the building could collapse. LeMessurier reported the vulnerability to Citicorp. A remediation plan was developed: welders would reinforce the bolted connections at night, working above the occupied