William LeMessurier realized there was a fundamental flaw in the design of Citicorp Center that could lead to its catastrophic failure and thousands of deaths in high winds. He secretly worked with others to reinforce the building by welding steel plates over vulnerable joints. The $8 million repair was completed before any storms could endanger it, though the public was not informed of the risk for almost 20 years, due to LeMessurier's honesty and efforts to avert disaster.

1.  You've taken on a design challenge and come up with
a solution that's been widely admired and won you
awards. But a year or so later, you realize there was a
mistake. There's something horribly wrong with your
design. And it's not just something cosmetic — a badly
resolved corner etc. — but a fundamental flaw that will
almost certainly lead to catastrophic failure. And that
failure will result not just in embarrassment, or
professional ruin, but death, the death of thousands of
people.
 You are the only person that knows that something's
wrong. What would you do?

2. Doing the Right
T hing
The Citicorp Center Case
William LeMessurier

3.  This sounds like a hypothetical question.
But it's not. It's the question that
structural engineer William LeMessurier
faced on a lonely July weekend about 30
years ago.

4.  Citicorp Center in New York with its distinctive forty-five degree
diagonal crown, the Citicorp building is one of the most
recognizable skyscrapers on the New York City skyline. With fifty-
nine stories, it's the third tallest building in midtown Manhattan,
and at the time of its completion it was the seventh-tallest building
in the world. At ground level, the huge skyscraper almost seems
to hover above Lexington Avenue, held aloft by four massive, 114-
foot-tall stilts which are located at the center of each side rather
than on the corners. This unusual architecture was one of
necessity– the structure had to be built around the landmark St.
Peter's Church– but the design left room for a serious engineering
flaw which went completely unnoticed during its construction and
initial use. Had the weakness not been accidentally discovered
and secretly fixed, the mighty skyscraper could have been
collapsed by a hard blast of air of wind without any warning.

5. Citicorp Center

6.  The building's structural skeleton was designed by an engineer
named William J. LeMessurier (pronounced "La Measure") in the
early 1970s. Making room for the St. Peter's church was a difficult
problem, but LeMessurier was a highly capable and creative
engineer. His design called for the building to sit atop nine-story-
tall stilts, one centered on each side with a specific geometry in
the structure's framing to take maximum advantage of the oddly
placed support columns. It also had a single, narrower column in
the center which housed the building's elevator banks and
provided additional strength to the framing. This design made
room for the church under the building's northwest corner, and
gave the giant structure a graceful, almost levitating effect.

9.  LeMessurier first became aware of the building's weakness in 1978, about
a year after its completion. An engineering student contacted him to ask
some technical questions about the design, which he was delighted to
address. The student's professor had expressed doubts regarding the
strength of a stilted skyscraper where the support columns were not on
the corners. "Listen, I want you to tell your teacher that he doesn't know
what the hell he's talking about," LeMessurier told the student, "because
he doesn't know the problem that had to be solved." He went on to
explain how the building's framing geometry worked perfectly with the
stilts in such positions, allowing it to withstand very forceful winds, even
from a diagonal angle.
 But the conversation got him thinking, and he started doing some
calculations on just how much diagonal wind the structure could
withstand. He was particularly interested in the effects of an engineering
change made during construction which had seemed caring at the time:
numerous joints were secured with bolts rather than welds. Normally such
a change was acceptable, but the Citicorp Center's design was unusually
sensitive to diagonal winds, which the builders hadn't realized. The results
of his calculations were troubling.

11.  He took his calculations to fellow engineer Alan
Davenport, who was an expert on the behavior of
buildings in high-wind conditions. Davenport found that
seventy-mile-per-hour gusts would be sufficient to
break the bolts holding the joints, resulting in structural
failure. Such winds were not unknown in New York,
indeed storms with such strength occurred about once
every sixteen years on average. Hurricane season was
fast approaching, and now only two men in the world
knew that Citicorp's new $175 million tower and its
occupants were vulnerable to destruction by
catastrophic collapse.

13.  Horrified, LeMessurier fled to his island hideaway on
Sebago Lake to refine the findings and consider his
options. Because he faced possible litigation,
bankruptcy, and professional disgrace he contemplated
suicide, but he was struck with the realization that he
held the information to initiate extraordinary events
which could save thousands of lives. The following day
he started making phone calls. After speaking with
corporate lawyers and consulting with Leslie
Robertson– an engineer who helped design the World
Trade Center– LeMessurier went to Cambridge to
inform Hugh Stubbins, Jr., the building's architect.
Stubbins winced when he heard the news.

15.  Together they flew to New York City to confront the executive officers of
Citicorp with the dilemma. "I have a real problem for you, sir,"
LeMessurier said to Citicorp's executive vice-president, John S. Reed.
The two men outlined the design flaw and described their proposed
solution: to systematically reinforce all 200+ bolted joints by welding two-
inch-thick steel plates over them.
 Work began immediately, and continued around the clock for three
months. Welders worked all night, and carpenters labored during the day.
In case of imminent disaster, an evacuation plan was put in place for the
surrounding area, but the general public knew nothing of the
circumstances… the press was on strike at that time, so news of the
repairs did not disseminate to the populace. About halfway into the repairs
Hurricane Ella formed, and it appeared to be on a collision course with
Manhattan, but fortunately the storm veered out to sea rather than testing
the limits of the half-repaired building. The reinforcements were
completed in September of 1978, and the entire structure was re-
evaluated for safety. Following the repairs, the building was found to be
one of the most sturdy skyscrapers in the world. Despite the success, the
crisis was kept hidden from the public for almost twenty years, until an
article appeared in the New Yorker in 1995.

17.  As for LeMessurier, the executives at Citicorp
asked no more than the $2 million his
insurance policy covered, despite the fact that
the repairs alone cost over $8 million. It is
generally thought that his honesty so
impressed the executives that they decided to
keep their lawyers at bay. It is clear that it
takes a lot of character to admit one's own
mistakes, but in accepting responsibility for this
flaw and then leading the repair effort, the
character shown by William J. LeMessurier
was nothing short of heroic.

18. Citicorp Center
standing over St.
Peter's church

19.  The story of William LeMessurier and
Citicorp Center was first told in a brilliant
New Yorker article by Joe Morgenstern in
1995, "The Fifty-Nine-Story Crisis."