text: 1978 engineering crisis Due to material changes during construction, the building as completed was vulnerable to collapse in high winds. LeMessurier's original design for the chevron load braces had used welded joints. To save money, Bethlehem Steel changed the plans in 1974 to use bolted joints, which was accepted by LeMessurier's office but not known to the engineer himself. Furthermore, LeMessurier originally only needed to calculate wind loads from perpendicular winds, as required under the building code; in typical buildings, loads from quartering winds at the corners would be less. In June 1978, after an inquiry from engineering student Diane Hartley, LeMessurier recalculated the wind loads on the building with quartering winds. LeMessurier found that quartering winds would significantly increase the load at the bolted joints. After conducting tests on the building's structural safety, he found that a wind capable of toppling Citicorp Center would have a 1-in-55 chance of occurring in an average year, or a 1-in-16 chance of happening if the tuned mass damper (TMD) on the roof was powered off.
  LeMessurier proposed welding steel plates over the bolted joints, and Karl Koch Erecting was hired for the welding process. Starting in August 1978, construction crews installed the welded panels at night. The fixes were completed that October, after which LeMessurier claimed that a wind strong enough to topple the building would have a 1-in-700 chance of occurring in any given year. The work was not publicized at the time, as it took place during the 1978 New York City newspaper strike and very few people were notified of the issue. Since no structural failure occurred, the extent of the engineering crisis was only publicly revealed in a lengthy article in The New Yorker in 1995. A National Institute of Standards and Technology reassessment of the engineering crisis in 2019, using modern technology, indicated that the quartering wind loads were not as severe as LeMessurier and Hartley had thought.