8:23
Citicorp Center | NYC skyscraper saved by a student’s question
https://www.youtube.com/watch?v=Bv2YQnT6pSoa
https://www.youtube.com/watch?v=Bv2YQnT6pSo
Tyler Ley
Published on Jun 8, 2018
In June 1978, the skyscraper's structural engineer, William LeMessurier, discovered a potentially fatal flaw in the building's design [Citygroup Center in Manhattan, New York, formerly known as the Citycorp Center, and now known by its address, 601 Lexington Avenue, in 2009, owned by Boston Properties]: the skyscraper's bolted joints were too weak to withstand 70-mile-per-hour wind gusts.
____________________________________
2:45
The Citicorp Building
https://www.youtube.com/watch?v=RwVNak-2-Xg
https://www.youtube.com/watch?v=RwVNak-2-Xg
WisconsinEngineerUWP
Published on May 18, 2012
____________________________________
https://en.wikipedia.org/wiki/Citigroup_Center
► http://www.theaiatrust.com/whitepapers/ethics/LeMessurier-Stands-Tall_A-Case-Study-in-Professional-Ethics.pdf
____________________________________
Diane Lee Hartley
23:34
► https://soundcloud.com/roman-mars/99-invisible-110-structural-integrity
____________________________________
http://www.slate.com/blogs/the_eye/2014/04/17/the_citicorp_tower_design_flaw_that_could_have_wiped_out_the_skyscraper.html
____________________________________
in the New Yorker story, the young man (college student working on her thesis project) is a young woman named, Diane Lee Hartley
► https://www.newyorker.com/magazine/1995/05/29/the-fifty-nine-story-crisis
City Perils
May 29, 1995 Issue
THE FIFTY-NINE-STORY CRISIS
By Joseph Morgenstern
The New Yorker, May 29, 1995 P. 45
CITY PERILS about a structural defect uncovered in June, 1978 in Citibank's $175 million Citicorp Center tower which could have caused it to collapse in the event of a strong hurricane. Tells about designer William J. LeMessurier, who was structural consultant to the architect High Stubbins, Jr. They set their 59-story tower on four massive nine-story-high stilts and used an unusual, chevron-shaped system of wind braces. LeMessurier had established the strength of those braces in perpendicular winds. Now, in the spirit of intellectual play, in his Harvard class, he wanted to see if they were just as strong in winds hitting from 45 degrees. He discovered the design flaw and during wind tunnel tests in Ontario learned the weakest joint was at the building's 30th floor. Describes the building's active motion damping system, built into the top of the structure. By Aug. 7, 1978, steel plates to correct the defect had been designed. Welders worked seven days a week in August, after office hours, to add the plates to the wind braces. Welding was completed in October. The bank agreed to hold Stubbins' firm harmless and to accept the $2 million payment from LeMessurier and his joint-venture partners; no litigation ever ensued. Eight years ago, Citicorp turned the building into a condominium, retaining the land and the shops but selling all the office space, to Japanese buyers, at a handsome profit.
Citicorp Center Tower: how failure was averted
08 December 2015
Sean Brady reflects on the Citicorp tower crisis when high rise engineer William LeMessurier owned up to a major design flaw and set about rectifying it
http://www.engineersjournal.ie/2015/12/08/citicorp-centre-tower-failure-averted/
Based on an article originally published in ‘The New Yorker’, Sean Brady reflects on the Citicorp tower crisis
____________________________________
► https://people.duke.edu/~hpgavin/cee421/citicorp1.htm
from welded joints to bolted joints
welded joints
stronger
expensive
labor intensive
bolted joints
weaker
cheaper
easier to install
But welded joints, which are labor-intensive and therefore expensive, can be needlessly strong; in most cases, bolted joints are more practical and equally safe. That was the position taken at the May meeting by a man from U.S. Steel, a potential bidder on the contract to erect the Pittsburgh towers. If welded joints were a condition, the project might be too expensive and his firm might not want to take it on.
"I spoke to Stanley Goldstein and said, 'Tell me about your success with those welded joints in Citicorp.' And Stanley said, 'Oh, didn't you know? They were changed--they were never welded at all, because Bethlehem Steel came to us and said they didn't think we needed to do it.'' Bethlehem, which built the Citicorp tower, had made the same objection--welds were stronger than necessary, bolts were the right way to do the job. On August 1, 1974, LeMessurier's New York office--actually a venture in conjunction with an old-line Manhattan firm called the Office of James Ruderman--had accepted Bethlehem's proposal.
The choice of bolted joints was technically sound and professionally correct.
Within this seemingly simple computation, however, lurks a powerful multiplier. At any given level of the building, the compression figure remains constant; the wind may blow harder, but the structure doesn't get any heavier. Thus, immense leverage can result from higher wind forces. In the Citicorp tower, the forty-per-cent increase in tension produced by a quartering wind became a hundred-and-sixty-per-cent increase on the building's bolts.
Precisely because of that leverage, a margin of safety is built into the standard formulas for calculating how strong a joint must be; these formulas are contained in an American Institute of Steel Construction specification that deals with joints in structural columns. What LeMessurier found in New York, however, was that the people on his team had disregarded the standard. They had chosen to define the diagonal wind braces not as columns but as trusses, which are exempt from the safety factor. As a result, the bolts holding the joints together were perilously few. "By then," LeMessurier says, "I was getting pretty shaky."
He later detailed these mistakes in a thirty-page document called "Project SERENE''; the acronym, both rueful and apt, stands for "Special Engineering Review of Events Nobody Envisioned."
http://www.openthefuture.com/wcarchive/2004/08/project_serene.html
https://people.duke.edu/~hpgavin/cee421/citicorp1.htm
BEFORE making a final judgment on how dangerous the bolted joints were, LeMessurier turned to a Canadian engineer named Alan Davenport, the director of the Boundary Layer Wind Tunnel Laboratory, at the University of Western Ontario, and a world authority on the behavior of buildings in high winds. During the Citicorp tower's design, Davenport had run extensive tests on scale models of the structure. Now LeMessurier asked him and his deputy to retrieve the relevant files and magnetic tapes. "If we were going to think about such things as the possibility of failure," LeMessurier says--the word "failure" being a euphemism for the Citicorp tower's falling down--"we would think about it in terms of the best knowledge that the state of the art can produce, which is what these guys could provide for me."
On July 26th, he flew to London, Ontario, and met with Davenport. Presenting his new calculations, LeMessurier asked the Canadians to evaluate them in the light of the original data. "And you have to tell me the truth," he added. "Don't go easy if it doesn't come out the right way." It didn't, and they didn't. The tale told by the wind-tunnel experts was more alarming than LeMessurier had expected. His assumption of a forty-per-cent increase in stress from diagonal winds was theoretically correct, but it could go higher in the real world, when storms lashed at the building and set it vibrating like a tuning fork. "Oh, my God," he thought, "now we've got that on top of an error from the bolts being under-designed." Refining their data further, the Canadians teased out wind-tunnel forces for each structural member in the building, with and without the tuned mass damper in operation; it remained for LeMessurier to interpret the numbers' meaning.
First, he went to Cambridge, where he talked to a trusted associate, and then he called his wife at their summer house in Maine. "Dorothy knew what I was up to," he says. "I told her, 'I think we've got a problem here, and I'm going to sit down and try to think about it.'" On July 28th, he drove to the northern shore of Sebago Lake, took an outboard motorboat a quarter of a mile across the water to his house on a twelve-acre private island, and worked through the wind-tunnel numbers, joint by joint and floor by floor.
The weakest joint, he discovered, was at the building's thirtieth floor; if that one gave way, catastrophic failure of the whole structure would follow. Next, he took New York City weather records provided by Alan Davenport and calculated the probability of a storm severe enough to tear that joint apart. His figures told him that such an event had a statistical probability of occurring as often as once every sixteen years--what meteorologists call a sixteen-year storm.
"That was very low, awesomely low," LeMessurier said, his voice hushed as if the horror of discovery were still fresh. "To put it another way, there was one chance in sixteen in any year, including that one." When the steadying influence of the tuned mass damper was factored in, the probability dwindled to one in fifty-five--a fifty-five-year storm. But the machine required electric current, which might fail as soon as a major storm hit.
As an experienced engineer, LeMessurier liked to think he could solve most structural problems, and the Citicorp tower was no exception. The bolted joints were readily accessible, thanks to Hugh Stubbins' insistence on putting the chevrons inside the building's skin rather than displaying them outside. With money and materials, the joints could be reinforced by welding heavy steel plates over them, like giant Band-Aids. But time was short; this was the end of July, and the height of the hurricane season was approaching. To avert disaster, LeMessurier would have to blow the whistle quickly on himself. That meant facing the pain of possible protracted litigation, probable bankruptcy, and professional disgrace. It also meant shock and dismay for Citicorp's officers and shareholders when they learned that the bank's proud new corporate symbol, built at a cost of a hundred and seventy-five million dollars, was threatened with collapse.
On the island, LeMessurier considered his options. Silence was one of them; only Davenport knew the full implications of what he had found, and he would not disclose them on his own. Suicide was another, if LeMessurier drove along the Maine Turnpike at a hundred miles an hour and steered into a bridge abutment, that would be that. But keeping silent required betting other people's lives against the odds, while suicide struck him as a coward's way out and--although he was passionate about nineteenth-century classical music--unconvincingly melodramatic. What seized him an instant later was entirely convincing, because it was so unexpected almost giddy sense of power. "I had information that nobody else in the world had," LeMessurier recalls. "I had power in my hands to effect extraordinary events that only I could initiate. I mean, sixteen years to failure--that was very simple, very clear-cut. I almost said, thank you, dear Lord, for making this problem so sharply defined that there's no choice to make.' '
____________________________________
When We Don't Like the Solution, We Deny the Problem
► https://science.slashdot.org/story/14/11/08/1416233/when-we-dont-like-the-solution-we-deny-the-problem
PUBLISHED November 6, 2014 IN Campus
Denying Problems When We Don’t Like the Solutions
By Duke Today Staff
https://today.duke.edu/2014/11/solutionaversion
A new study from Duke University finds that people will evaluate scientific evidence based on whether they view its policy implications as politically desirable. If they don't, then they tend to deny the problem even exists. “Logically, the proposed solution to a problem, such as an increase in government regulation or an extension of the free market, should not influence one’s belief in the problem. However, we find it does,” said co-author Troy Campbell, a Ph.D. candidate at Duke's Fuqua School of Business. “The cure can be more immediately threatening than the problem.”
____________________________________
http://www.openthefuture.com/wcarchive/2004/08/project_serene.html
► https://www.pbs.org/wgbh/buildingbig/wonder/structure/citicorp.html
Northwest corner of Citicorp Building towering over St. Peter’s Lutheran Church, New York, New York
In 1978, the skyscraper's chief structural engineer, William LeMessurier, discovered a potentially fatal flaw in the building's design: the skyscraper's bolted joints were too weak to withstand 70-mile-per-hour wind gusts. With hurricane season fast approaching, LeMessurier took no chances. He convinced Citicorp officers to hire a crew of welders to repair the fragile building. For the next three months, a construction crew welded two-inch-thick steel plates over each of the skyscraper's 200 bolted joints, permanently correcting the problem.
____________________________________
9:57
How Manhattan escaped tragedy
https://www.youtube.com/watch?v=TZhgTewKhTQ
https://www.youtube.com/watch?v=TZhgTewKhTQ
flaxious
Published on Oct 21, 2010
____________________________________
https://faculty.arch.tamu.edu/media/cms_page_media/4433/Citicorp.pdf
Video unavailable
This video is no longer available because the YouTube account associated with this video has been terminated.
https://www.youtube.com/watch?v=bXpyukjQoGw
https://www.youtube.com/watch?v=bXpyukjQoGw
____________________________________
____________________________________
Diane Lee Hartley
23:34
► https://soundcloud.com/roman-mars/99-invisible-110-structural-integrity
____________________________________
http://www.slate.com/blogs/the_eye/2014/04/17/the_citicorp_tower_design_flaw_that_could_have_wiped_out_the_skyscraper.html
____________________________________
in the New Yorker story, the young man (college student working on her thesis project) is a young woman named, Diane Lee Hartley
► https://www.newyorker.com/magazine/1995/05/29/the-fifty-nine-story-crisis
City Perils
May 29, 1995 Issue
THE FIFTY-NINE-STORY CRISIS
By Joseph Morgenstern
The New Yorker, May 29, 1995 P. 45
CITY PERILS about a structural defect uncovered in June, 1978 in Citibank's $175 million Citicorp Center tower which could have caused it to collapse in the event of a strong hurricane. Tells about designer William J. LeMessurier, who was structural consultant to the architect High Stubbins, Jr. They set their 59-story tower on four massive nine-story-high stilts and used an unusual, chevron-shaped system of wind braces. LeMessurier had established the strength of those braces in perpendicular winds. Now, in the spirit of intellectual play, in his Harvard class, he wanted to see if they were just as strong in winds hitting from 45 degrees. He discovered the design flaw and during wind tunnel tests in Ontario learned the weakest joint was at the building's 30th floor. Describes the building's active motion damping system, built into the top of the structure. By Aug. 7, 1978, steel plates to correct the defect had been designed. Welders worked seven days a week in August, after office hours, to add the plates to the wind braces. Welding was completed in October. The bank agreed to hold Stubbins' firm harmless and to accept the $2 million payment from LeMessurier and his joint-venture partners; no litigation ever ensued. Eight years ago, Citicorp turned the building into a condominium, retaining the land and the shops but selling all the office space, to Japanese buyers, at a handsome profit.
Citicorp Center Tower: how failure was averted
08 December 2015
Sean Brady reflects on the Citicorp tower crisis when high rise engineer William LeMessurier owned up to a major design flaw and set about rectifying it
http://www.engineersjournal.ie/2015/12/08/citicorp-centre-tower-failure-averted/
Based on an article originally published in ‘The New Yorker’, Sean Brady reflects on the Citicorp tower crisis
____________________________________
► https://people.duke.edu/~hpgavin/cee421/citicorp1.htm
from welded joints to bolted joints
welded joints
stronger
expensive
labor intensive
bolted joints
weaker
cheaper
easier to install
But welded joints, which are labor-intensive and therefore expensive, can be needlessly strong; in most cases, bolted joints are more practical and equally safe. That was the position taken at the May meeting by a man from U.S. Steel, a potential bidder on the contract to erect the Pittsburgh towers. If welded joints were a condition, the project might be too expensive and his firm might not want to take it on.
"I spoke to Stanley Goldstein and said, 'Tell me about your success with those welded joints in Citicorp.' And Stanley said, 'Oh, didn't you know? They were changed--they were never welded at all, because Bethlehem Steel came to us and said they didn't think we needed to do it.'' Bethlehem, which built the Citicorp tower, had made the same objection--welds were stronger than necessary, bolts were the right way to do the job. On August 1, 1974, LeMessurier's New York office--actually a venture in conjunction with an old-line Manhattan firm called the Office of James Ruderman--had accepted Bethlehem's proposal.
The choice of bolted joints was technically sound and professionally correct.
Within this seemingly simple computation, however, lurks a powerful multiplier. At any given level of the building, the compression figure remains constant; the wind may blow harder, but the structure doesn't get any heavier. Thus, immense leverage can result from higher wind forces. In the Citicorp tower, the forty-per-cent increase in tension produced by a quartering wind became a hundred-and-sixty-per-cent increase on the building's bolts.
Precisely because of that leverage, a margin of safety is built into the standard formulas for calculating how strong a joint must be; these formulas are contained in an American Institute of Steel Construction specification that deals with joints in structural columns. What LeMessurier found in New York, however, was that the people on his team had disregarded the standard. They had chosen to define the diagonal wind braces not as columns but as trusses, which are exempt from the safety factor. As a result, the bolts holding the joints together were perilously few. "By then," LeMessurier says, "I was getting pretty shaky."
He later detailed these mistakes in a thirty-page document called "Project SERENE''; the acronym, both rueful and apt, stands for "Special Engineering Review of Events Nobody Envisioned."
http://www.openthefuture.com/wcarchive/2004/08/project_serene.html
https://people.duke.edu/~hpgavin/cee421/citicorp1.htm
BEFORE making a final judgment on how dangerous the bolted joints were, LeMessurier turned to a Canadian engineer named Alan Davenport, the director of the Boundary Layer Wind Tunnel Laboratory, at the University of Western Ontario, and a world authority on the behavior of buildings in high winds. During the Citicorp tower's design, Davenport had run extensive tests on scale models of the structure. Now LeMessurier asked him and his deputy to retrieve the relevant files and magnetic tapes. "If we were going to think about such things as the possibility of failure," LeMessurier says--the word "failure" being a euphemism for the Citicorp tower's falling down--"we would think about it in terms of the best knowledge that the state of the art can produce, which is what these guys could provide for me."
On July 26th, he flew to London, Ontario, and met with Davenport. Presenting his new calculations, LeMessurier asked the Canadians to evaluate them in the light of the original data. "And you have to tell me the truth," he added. "Don't go easy if it doesn't come out the right way." It didn't, and they didn't. The tale told by the wind-tunnel experts was more alarming than LeMessurier had expected. His assumption of a forty-per-cent increase in stress from diagonal winds was theoretically correct, but it could go higher in the real world, when storms lashed at the building and set it vibrating like a tuning fork. "Oh, my God," he thought, "now we've got that on top of an error from the bolts being under-designed." Refining their data further, the Canadians teased out wind-tunnel forces for each structural member in the building, with and without the tuned mass damper in operation; it remained for LeMessurier to interpret the numbers' meaning.
First, he went to Cambridge, where he talked to a trusted associate, and then he called his wife at their summer house in Maine. "Dorothy knew what I was up to," he says. "I told her, 'I think we've got a problem here, and I'm going to sit down and try to think about it.'" On July 28th, he drove to the northern shore of Sebago Lake, took an outboard motorboat a quarter of a mile across the water to his house on a twelve-acre private island, and worked through the wind-tunnel numbers, joint by joint and floor by floor.
The weakest joint, he discovered, was at the building's thirtieth floor; if that one gave way, catastrophic failure of the whole structure would follow. Next, he took New York City weather records provided by Alan Davenport and calculated the probability of a storm severe enough to tear that joint apart. His figures told him that such an event had a statistical probability of occurring as often as once every sixteen years--what meteorologists call a sixteen-year storm.
"That was very low, awesomely low," LeMessurier said, his voice hushed as if the horror of discovery were still fresh. "To put it another way, there was one chance in sixteen in any year, including that one." When the steadying influence of the tuned mass damper was factored in, the probability dwindled to one in fifty-five--a fifty-five-year storm. But the machine required electric current, which might fail as soon as a major storm hit.
As an experienced engineer, LeMessurier liked to think he could solve most structural problems, and the Citicorp tower was no exception. The bolted joints were readily accessible, thanks to Hugh Stubbins' insistence on putting the chevrons inside the building's skin rather than displaying them outside. With money and materials, the joints could be reinforced by welding heavy steel plates over them, like giant Band-Aids. But time was short; this was the end of July, and the height of the hurricane season was approaching. To avert disaster, LeMessurier would have to blow the whistle quickly on himself. That meant facing the pain of possible protracted litigation, probable bankruptcy, and professional disgrace. It also meant shock and dismay for Citicorp's officers and shareholders when they learned that the bank's proud new corporate symbol, built at a cost of a hundred and seventy-five million dollars, was threatened with collapse.
On the island, LeMessurier considered his options. Silence was one of them; only Davenport knew the full implications of what he had found, and he would not disclose them on his own. Suicide was another, if LeMessurier drove along the Maine Turnpike at a hundred miles an hour and steered into a bridge abutment, that would be that. But keeping silent required betting other people's lives against the odds, while suicide struck him as a coward's way out and--although he was passionate about nineteenth-century classical music--unconvincingly melodramatic. What seized him an instant later was entirely convincing, because it was so unexpected almost giddy sense of power. "I had information that nobody else in the world had," LeMessurier recalls. "I had power in my hands to effect extraordinary events that only I could initiate. I mean, sixteen years to failure--that was very simple, very clear-cut. I almost said, thank you, dear Lord, for making this problem so sharply defined that there's no choice to make.' '
____________________________________
When We Don't Like the Solution, We Deny the Problem
► https://science.slashdot.org/story/14/11/08/1416233/when-we-dont-like-the-solution-we-deny-the-problem
PUBLISHED November 6, 2014 IN Campus
Denying Problems When We Don’t Like the Solutions
By Duke Today Staff
https://today.duke.edu/2014/11/solutionaversion
A new study from Duke University finds that people will evaluate scientific evidence based on whether they view its policy implications as politically desirable. If they don't, then they tend to deny the problem even exists. “Logically, the proposed solution to a problem, such as an increase in government regulation or an extension of the free market, should not influence one’s belief in the problem. However, we find it does,” said co-author Troy Campbell, a Ph.D. candidate at Duke's Fuqua School of Business. “The cure can be more immediately threatening than the problem.”
____________________________________
http://www.openthefuture.com/wcarchive/2004/08/project_serene.html
► https://www.pbs.org/wgbh/buildingbig/wonder/structure/citicorp.html
Northwest corner of Citicorp Building towering over St. Peter’s Lutheran Church, New York, New York
In 1978, the skyscraper's chief structural engineer, William LeMessurier, discovered a potentially fatal flaw in the building's design: the skyscraper's bolted joints were too weak to withstand 70-mile-per-hour wind gusts. With hurricane season fast approaching, LeMessurier took no chances. He convinced Citicorp officers to hire a crew of welders to repair the fragile building. For the next three months, a construction crew welded two-inch-thick steel plates over each of the skyscraper's 200 bolted joints, permanently correcting the problem.
____________________________________
9:57
How Manhattan escaped tragedy
https://www.youtube.com/watch?v=TZhgTewKhTQ
https://www.youtube.com/watch?v=TZhgTewKhTQ
flaxious
Published on Oct 21, 2010
____________________________________
https://faculty.arch.tamu.edu/media/cms_page_media/4433/Citicorp.pdf
Video unavailable
This video is no longer available because the YouTube account associated with this video has been terminated.
https://www.youtube.com/watch?v=bXpyukjQoGw
https://www.youtube.com/watch?v=bXpyukjQoGw
____________________________________
16:41
MEGACITIES: Reality or Fiction? [Architecture in Sci-Fi]
https://www.youtube.com/watch?v=G5GL836kpls
https://www.youtube.com/watch?v=G5GL836kpls
DamiLee
Nov 11, 2022
Sign up to Milanote for free with no time-limit: https://milanote.com/damilee
MEGACITIES: Reality or Fiction? [Architecture in Sci-Fi]
https://www.youtube.com/watch?v=G5GL836kpls
https://www.youtube.com/watch?v=G5GL836kpls
DamiLee
Nov 11, 2022
Sign up to Milanote for free with no time-limit: https://milanote.com/damilee
____________________________________