What would you do if someone called attention to a possible catastrophic design flaw in a project that you had designed and that was already completed?

A. Not say anything and hope for the best?
B. Try to blame it on someone else?
C. Contact the customer and work on making it right?

If you chose "C." you'd have the right answer and you'd be in the company of William LeMessurier, the structural engineer who worked on the demanding Citigroup Center in New York City. The interesting thing is that while the flaw was discovered in 1978 and repair began soon after the discovery - the public wasn't made aware of the changes and repairs until 1995.

The Citigroup Center was an engineering challenge from the very beginning - the northwest corner of the site that was chosen for the building was occupied by St.Peter's Lutheran Church. The church agreed to demolish the church to make way for the skyscraper under one condition: a new church would be built on the same corner with no part of the Citigroup Center touching it and no columns going through it. Impossible? Some architects thought so!

Le Messurier set the 59-story tower on four massive114-foot (35-m)-high columns, positioned at the center of each side, rather than at the corners. This design allowed the northwest corner of the building to cantilever 72feet (22 m) over the new church. To accomplish these goals LeMessurier designed a system of stacked load-bearing braces, in the form of inverted chevrons. Each chevron would redirect the massive loads to their center, then downward into the ground through the uniquely-positioned columns. Problem solved - right? WRONG!!!

In 1978, a Princeton University engineering student posed a question to Lemessurier that resulted in his discovery of a potentially fatal flaw in construction - during construction the originally planned welded joints were changed to bolted joints after the building's plans had been approved - the bolted joints were too weak to withstand 70-mile-per-hour (hurricane force) winds. Not too many hurricanes hit NYC you say? WRONG AGAIN!

Hurricane season was fast approaching when LeMessurier decided to approach Citicorp directly and advise them to take swift action to repair the flaw. He convinced them to hire a crew of welders to work on the building without informing the public (conveniently there was a press strike at the time). For three months, working stealthily through the night, the crew worked on welding 2-inch-thick steel plates over the building's 200 bolted joints.

UH-OH! Six weeks into the work Hurricane Ella was headed for New York from Cape Hatteras and the work was only half-finished! Thankfully the storm veered out to sea and the welders were able to finish and permanently correct the problem.

Because no disaster ensued and the flaw was corrected - the situation wasn't made public for almost 20 years! LeMessurier was criticized for his handling of the situation but the example of his direct intervention with Citicorp is now held up as an example of engineering ethics in several textbooks.

WHAT DO YOU THINK? - Would you have handled the situation differently? Agree or disagree with LeMessurier's actions? Let us know at marketing@insightautomation.cc