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Sat Jun 26, 2021, 09:31 PM

Speaking of troubled buildings...Citicorp Center, NYC

From Wikipedia

Due to material changes during construction, the building as initially completed was structurally unsound. LeMessurier's original design for the chevron load braces 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.[22] Furthermore, according to The New Yorker, LeMessurier originally only needed to calculate wind loads from perpendicular winds under the building code; in typical buildings, loads from quartering winds at the corners would be less.[22][159] In June 1978, after an inquiry from Princeton University engineering student Diane Hartley, LeMessurier recalculated the wind loads on the building with quartering winds.[159][f] He found that, for four of the eight tiers of chevrons, such winds would create a 40 percent increase in wind loads and a 160 percent increase in load at the bolted joints.[22]

Citicorp Center's use of bolted joints and the increased loads from quartering winds would not have caused concern if these issues had been isolated from each other. However, the combination of the two findings prompted LeMessurier to run tests on the structural safety.[103] The original welded-joint design could withstand the load from straight-on and quartering winds, but a 75-mile-per-hour (121 km/h) hurricane force quartering wind would exceed the strength of the bolted-joint chevrons.[99] With the tuned mass damper active, LeMessurier estimated that a wind capable of toppling the building would occur on average once every 55 years.[162][161] If the tuned mass damper could not function due to a power outage, a wind strong enough to cause the building's collapse would occur once every 16 years on average.[162] LeMessurier also discovered that his firm had used New York City's truss safety factor of 1:1 instead of the column safety factor of 1:2.[99]

LeMessurier debated how to address the issue before ultimately contacting Stubbins's lawyer. LeMessurier then contacted Citicorp's lawyers, the latter of which hired Leslie E. Robertson as an expert adviser.[163] Citicorp accepted LeMessurier's proposal to weld steel plates over the bolted joints, and Karl Koch Erecting was hired for the welding process.[104] Very few people were made aware of the issue, besides Citicorp leadership, mayor Ed Koch, acting buildings commissioner Irving E. Minkin, and the head of the welder's union.[99][104] Starting in August 1978, construction crews installed the welded panels at night. Officials made no public mention of any possible structural issues, and the city's three major newspapers had gone on strike.[88][104] The work continued despite the threat of Hurricane Ella several weeks after the repairs started.[99][164] Repairs were completed in October 1978, before the media resumed publishing. LeMessurier claimed a wind strong enough to topple the building would only occur once every 700 years.[88][165] Stubbins and LeMessurier covered all of the repair costs, which were estimated to be several million dollars.[165] Since no structural failure occurred, the work was only publicized in a lengthy article in The New Yorker in 1995

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Reply Speaking of troubled buildings...Citicorp Center, NYC (Original post)
Raven Jun 2021 OP
PoliticAverse Jun 2021 #1
Demovictory9 Jun 2021 #2
smirkymonkey Jun 2021 #3
róisín_dubh Jun 2021 #4
smirkymonkey Jun 2021 #5

Response to Raven (Original post)

Sat Jun 26, 2021, 09:37 PM

1. And then there is...

Engineer figures $100 million fix to leaning Millennium Tower in San Francisco

...

The tower has settled more than 17 inches, tilting four inches across its footprint — after the structure’s weight and nearby construction projects caused soil consolidation and lateral displacement.


From: https://www.californiaconstructionnews.com/2020/08/17/engineer-figures-100-million-fix-to-leaning-millennium-tower-in-san-francisco/

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Response to Raven (Original post)

Sun Jun 27, 2021, 02:54 AM

2. ..

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Response to Raven (Original post)

Sun Jun 27, 2021, 03:16 AM

3. I used to work right across the street from the Citicorp building on 3rd Ave.

 

That building always kind of freaked me out, not just knowing the history, but I am just kind of one of those people who is very mistrustful of modern technology/structures/mechanics to begin with.

It's completely irrational, I know that, but I just have so little faith in anything man made and operated. It would take a great leap of faith for me to believe that it will not eventually collapse, fall out of the sky, explode, or self-destruct in some other way. It's not a great way to live, I would much prefer not to think that way. It causes a lot of anxiety.

Most of the time, nothing happens, but I am one of those people that thinks about what COULD happen, just like what did happen with this building collapsing on Thursday.

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Response to smirkymonkey (Reply #3)

Sun Jun 27, 2021, 06:46 AM

4. I was sitting atop a pyramid in Mexico and...

had an overwhelming surge of fear that the pyramid would collapse. Not logical, as it's stood there for like 1100 years. I immediately scooted down the steps on my bum (I'm afraid of heights as well).
I know the feeling you're describing.

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Response to róisín_dubh (Reply #4)

Sun Jun 27, 2021, 01:05 PM

5. Yes, I think it must be a certain kind of phobia or something.

 

I always wonder if other people have these fears.

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