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00:00This is Citicorp Center.
00:02In the summer of 1978, it had been open for less than a year
00:05when its structural engineer, Bill LeMessur, made a terrifying discovery.
00:09His cutting-edge skyscraper, an engineering marvel, had a fatal flaw.
00:14Winds of just 110 kilometers per hour could cause it to collapse in the middle of Manhattan,
00:21potentially killing thousands.
00:23Over 200,000 people lived and worked in the surrounding area,
00:26and hurricane season was only weeks away.
00:30Here I am, the only man in the world who knew this.
00:34This thing is in real trouble.
00:37LeMessur faced a stark choice.
00:39He could stay silent and hope for the best,
00:42or he could try to fix it and risk professional ruin and mass panic.
00:47But Citicorp Center had a 100% probability of total collapse by the end of the century.
00:52How could he save New York from a near-certain disaster?
00:56And how was this allowed in the first place?
01:00Veritasium producer and engineer Henry Van Dyke traveled to New York to investigate further.
01:05So in the 1960s, the financial giant Citicorp was trying to build a new headquarters in Manhattan.
01:10So just down the street from the original headquarters was this entire city block,
01:15which was up for sale.
01:16Well, everything except for this church, St. Peter's.
01:19So Citicorp came to the pastor, Ralph Peterson, and asked,
01:22what's it going to take for you guys to leave?
01:24And he came back and said, we're not leaving.
01:27Anything that Citicorp builds has to involve the church as part of it.
01:30What the pastor wanted was for the church to have its own separate identity.
01:34So eventually they agreed on two things.
01:36One was to replace this old, crumbling, gothic church with a brand new one,
01:40which you see in front of you.
01:41And the second thing was that the church had to be physically distinct from the new tower.
01:47In other words, it had to be completely independent.
01:49And again, most importantly, two-thirds of the space above the church had to be free and clear, had to be open.
02:00Citicorp then hired architect Hugh Stubbins to design the tower and the church
02:04and build a measure as the structural engineer.
02:08Stubbins explained the constraints they faced.
02:10The church needed to be in the exact same spot and they needed to build the tower around it.
02:15If they were to maximize the floor area, they would have to notch out one corner of the tower for the church.
02:20La Measure agreed that could work.
02:22But why not notch two, three, or even all four corners?
02:27Essentially constructing the skyscraper on stilts.
02:31So it's probably the first time in history that an engineer has come to an architect and said,
02:35let's make our job harder for us.
02:36The stilts would serve two main purposes.
02:40First, they would need to support at least half of the building's gravity load.
02:44The rest would be held up by a larger central column.
02:48Second, they would need to withstand the load due to high winds.
02:52But unlike an ordinary structure, the stilts wouldn't be at the corners.
02:56They would be at the center of each face.
02:59Imagine a chair, and instead of the columns or the supports on each corner of the chair,
03:07it's at the midpoint of each side.
03:10Obviously, it's not an ideal situation.
03:13It doesn't seem very stable.
03:14Exactly.
03:15So it created an engineering problem.
03:18As LeMessure considered the problem, he suddenly had a flash of inspiration.
03:24He grabbed a napkin and sketched out an idea.
03:27He drew six layers of diagonal braces up each face of the tower.
03:31These chevrons would transfer the forces to the middle of each face and down to the stilts.
03:36Now we have to see the gravity loads, right?
03:40But now here's the trick.
03:42The gravity loads are coming down the column.
03:44When they get to the brace, they need to find their way into the brace.
03:49Okay.
03:50So what you do is you take out that column right there.
03:52There is no way that load can jump over and go to that column.
03:57And now they're coming down into the braces.
03:58They get down to the bottom here.
04:00And now they continue to go down.
04:02You take that column out.
04:03It has nowhere to go except into the brace.
04:05By removing the columns at the top and middle of each chevron,
04:10every tier acted as a separate unit.
04:13They were only connected to the braces and through the central core.
04:16So every eight stories, half of the gravity load would be forced
04:20through the chevrons to the mid-face columns, leading down to the stilts.
04:24Can you tell me how big of a new idea was this?
04:28Yeah.
04:29Well, this particular system was entirely unique.
04:32Driven by the placement of the columns, driven by the conditions of the building.
04:37Satisfied the chevrons could transfer the gravity load,
04:40LeMessur turned his attention to the second problem, the wind.
04:45When wind hits the left side of a normal building with corner columns,
04:48the entire frame deforms like this.
04:51So to reduce this deformation, we could strengthen these joints.
04:55But there's a better way.
04:57Because beams and columns are much stronger in compression or tension than they are with
05:01bending loads.
05:02So if we add diagonal bracing, they can carry this horizontal load.
05:07The beams sort of act like springs.
05:09When they're compressed, they push on the joints.
05:12When they're stretched, they pull inwards.
05:14With braces like these, the wind load compresses this diagonal and stretches this one.
05:19The left column pulls down in tension, and the right column pushes up in compression.
05:24Where the braces meet, they both push the bottom beam to the right.
05:28This stretches the left side and compresses the right one.
05:32But this floor is the top of the next chevron.
05:34So this lower section is carrying the force from the layer above it,
05:38and the normal wind load from the side.
05:40And this keeps happening at every chevron.
05:43So the wind load builds up as you go down the building.
05:45But Citicorp can't have corner columns like this because of the gravity load.
05:50So in the wind, this entire triangle wants to rotate like this.
05:54And to prevent that from happening, this chevron pulls down by going into tension,
05:58and the far chevron pushes up in compression.
06:01The top and bottom beams are again forced into compression and tension.
06:04The wind load ends up wrapping around the entire building.
06:07So every chevron works to transfer the wind load to the section below.
06:12When we think about skyscrapers, like how big of a deal is wind?
06:15If we made a skyscraper here, you know, out of all these different things,
06:19you push with your phone, you get a certain amount of force.
06:21But then you push on my phone as well with a certain amount of force,
06:24but your phone is also pushing on my phone.
06:26And so that's the shear in the building, what we call the building shear.
06:29It increases as you go down the building.
06:32You know, at the 10th floor, you may have a smaller force than at the 60th floor,
06:36but the total force of the 10th floor is like carrying everything above it.
06:40So it's much bigger than what's going on at the 60th floor.
06:44So these chevrons were key to LeMessure's design.
06:47But the braces were massive, almost 40 meters long end to end.
06:52So even if you could fabricate a steel brace that long,
06:55there would be no way to get it through Manhattan.
06:57So instead, it was sent in pieces to be welded together on site.
07:03The chevron bracing solved the wind and gravity load issues,
07:07but it also created a different problem.
07:11Because of the chevron bracing system,
07:14they were able to save a lot of money and weight.
07:18It was a lighter construct than most other buildings in New York.
07:23It was 22 pounds a square foot, which is very light.
07:26Unfortunately, that made the building swayable.
07:31It could move in the wind.
07:32That wasn't necessarily a structural problem.
07:36It was just, it could have been uncomfortable for the patrons.
07:41The way they could solve this was just,
07:42let's add more structural steel and make it a lot stiffer.
07:44But the solution that LeMessure came up with was far more elegant.
07:49He adopted something that had been regularly used in bridges, power lines, and ships,
07:54but never before in a building.
07:57A tuned mass damper, or TMD.
08:00So we're here at Stark Laboratories, and I'm not with Iron Man,
08:03but instead the Columbia Space Initiative,
08:06a student team here on campus who has helped us build
08:08this incredible tuned mass damper kind of system.
08:12We'll use this cart to represent a building.
08:15By pulling it back and releasing it,
08:17we can excite its resonant frequency.
08:19And then we'll put on a little pendulum, aluminum rod, and a mass at the bottom.
08:25As the building sways,
08:27it transfers some of its kinetic energy to the pendulum,
08:30which starts to swing.
08:32Then some of its energy is dissipated through friction at the hinge.
08:36The pendulum and the building oscillate out of phase from each other.
08:39So every time the building pulls the pendulum in a different direction,
08:43more energy is lost,
08:45significantly damping the sway of the tower.
08:48But this system needs to be carefully tuned
08:50so it has the same frequency as the building itself,
08:53and the right amount of friction.
08:56So first, the mass needs to be at least 1-5% of the building's weight to be effective.
09:02And we tune the frequency of the TMD by adjusting the length of the pendulum.
09:06I assume engineers do math around this thing,
09:08but we're just doing it by feel.
09:12Second, by loosening or tightening the bolt,
09:14we can tune the amount of damping.
09:16We need to dissipate more energy from friction at the hinge
09:19to stop the swaying faster.
09:21We just tighten the stop bolt
09:22to make the whole system a little bit,
09:25you know, add a little bit more resistance.
09:26And we'll see if we can dampen it now further.
09:32Woo-hoo!
09:33Much different, yeah.
09:34Yeah, that looked great.
09:35That was so quick.
09:36Yeah, that was.
09:36It is cool when an experiment works.
09:39It does not always happen.
09:42There are many different types of TMDs,
09:44like pendulums, liquid columns,
09:46and a large mass on springs.
09:49LeMessure used this last one in Citicorp.
09:52What you see is a mass of concrete,
09:55which is 29 feet square
09:56and about 8 feet thick
09:58and weighs 400 tons.
10:01It was installed on the top floor,
10:03and it's affectionately known as
10:05that great block of cheese.
10:07As Citicorp sways to one side,
10:10the block starts to move in the same direction.
10:13Some energy is dissipated through separate viscous dampers.
10:16Citicorp's oscillations are damped
10:18through those energy losses
10:19as the block oscillates out of phase
10:22to the building's motion.
10:24LeMessure expected the damper
10:25to reduce the amplitude of swaying
10:27by roughly 50%,
10:28and he saved around $4 million
10:30by not needing an additional
10:322,800 tons of structural steel.
10:36With both the chevron bracing
10:38to channel forces to the stilts
10:39and the tuned mass damper to reduce sway,
10:42LeMessure was convinced
10:43the building was structurally sound.
10:46On Citicorp Center's opening day in 1977,
10:49it was the 11th tallest building in the world.
10:51It was described by the press
10:53as an acrobatic act of architecture.
10:56Later, the American Institute of Architects
10:59even gave it an honor award,
11:01calling it a tour de force
11:02as a stylish silhouette in the skyline,
11:04and for the pedestrian,
11:06a hovering cantilevered hulk.
11:09So then it's going swimmingly
11:11for years, right?
11:13Well, it's going swimmingly
11:14for about a year.
11:17But the first hint of trouble
11:19came in May 1978.
11:20LeMessure was talking with another client
11:23about welding similar chevron braces.
11:26The architect and the steel fabricator
11:28said, tell me,
11:29how did those welded braces work out?
11:32Seems like overkill, they thought.
11:34And LeMessure said, yeah, they were fine.
11:36Let me call my guys in New York
11:38and I'll check.
11:39So he put the call into his office
11:41in New York and they say,
11:43oh, Bill, didn't you know
11:45we bolted those connections?
11:47The contractor had suggested
11:49saving a quarter of a million dollars
11:51by using bolts to attach the braces
11:53instead of welds.
11:54And LeMessure's firm had agreed.
11:56There is nothing that says
11:58a bolt is inherently worse
12:00or better than a weld.
12:01You use them in different circumstances
12:02for different reasons.
12:04But it's a little surprising
12:05to find out.
12:07I thought the connections
12:07in this tour de force,
12:09one-of-a-kind skyscraper,
12:11you know, that's on the cutting edge
12:12of structural engineering
12:13was connected one way,
12:15but apparently it's connected another way.
12:17But if the braces are going like this,
12:20where are they going to go?
12:21You know, you only need the weld
12:23when the braces are going like this.
12:25Since the gravity load
12:26was always compressing the braces,
12:28some of the chevrons
12:29only went into tension
12:30under very high winds.
12:32And even then,
12:33it wasn't a lot of tension.
12:35LeMessure trusted that his team
12:36did the right calculations
12:37and the substitution was fine.
12:40Logical even.
12:43But around a month later,
12:44LeMessure got a phone call
12:45from a student who wanted
12:46to ask some questions
12:47about the Citicorp center.
12:48And his teacher said to him,
12:50that engineer didn't know
12:51what he's doing
12:52and nobody should put
12:52the columns in the middle,
12:54they should put them in the corners.
12:56That's silly.
12:57And I told the student,
12:58I said, well,
12:59your professor's full of it,
13:01he doesn't understand
13:02the problem we had to solve.
13:04LeMessure went through
13:05the calculations with the student
13:06to reassure him
13:07the stilts were in the right place.
13:09But the interesting thing is,
13:11is in that moment,
13:12he's thinking about
13:14wind loads from all directions.
13:16You know, late spring,
13:18early summer of 1978,
13:20Bill LeMessure is working
13:21on the Back Bay Hilton Hotel
13:23that in plan forms a triangle,
13:25not a rectangle.
13:27Now you've got a triangle,
13:29what's your orthogonal direction?
13:31You just have to give up
13:32and say,
13:33we're going to analyze it
13:34from every direction.
13:35That's going on
13:37the moment that Bill LeMessure
13:38gets this phone call.
13:40Then I called him back
13:41and pointed out to him
13:42that there's some peculiar things
13:43about this building.
13:44The worst loading case
13:46was not the diagonal,
13:47but it was the ordinary wind
13:48that everybody thinks about.
13:49The wind pushes straight
13:50on the building.
13:51That was the critical case.
13:53He said, you know what?
13:53I've been getting all these calls
13:54from all these people.
13:55I'm going to sit down
13:57and explain this thing.
13:59He decided to double check
14:00what happens to the building
14:01if wind is hitting
14:02a corner of the building,
14:04not straight on
14:05one of the faces.
14:06These are also known
14:07as quartering winds.
14:09So he split the wind
14:10into its perpendicular components.
14:11So the west side and north side
14:13are hit by the force
14:15divided by the square root of two.
14:17He computed the forces for each
14:18as we did before
14:19and summed up the result.
14:21But then he noticed
14:23something strange.
14:24And now we look at the diagonals,
14:27the stresses in half of them vanish
14:29and in the other half, double.
14:32Since the force on each side
14:34was F over the square root of two,
14:36these beams get double that.
14:38Compared to LeMessure's calculations
14:40for the perpendicular wind load,
14:41the forces here were 40% higher.
14:45So 1.4 by itself
14:47is not enough to wreck havoc.
14:50Okay.
14:51It may be, but it may not be.
14:53Okay.
14:53So then the question is,
14:54well, what happens?
14:56This increase in forces
14:58wouldn't have mattered
14:59in the original design
15:00since the chevrons
15:01were fully welded together.
15:03But that wasn't the case anymore.
15:05LeMessure remembered
15:06his earlier phone call.
15:08The welds holding the chevrons together
15:10were swapped for bolts.
15:12How did his team calculate
15:14the number of bolts per joint?
15:16Did they consider quartering winds?
15:18It would be a miracle
15:19if they ever thought that through
15:21to think about the diagonal wind.
15:23It just wasn't in the nature of anybody.
15:26So I had a bit of a worry.
15:29I didn't panic right away,
15:31but I decided to go down
15:32to New York to my office.
15:34LeMessure requested
15:35the building diagrams
15:36and poured over
15:37all of the connections.
15:38He looked at how his firm
15:40calculated the number of bolts.
15:42There was no question
15:42they had taken the straight-on wind,
15:44not the diagonal wind.
15:46Although wind speed
15:47is highest at the top of the tower,
15:48the wind shear builds up
15:50as you go lower.
15:51Looking at this brace
15:52around halfway down the tower,
15:54the perpendicular wind load
15:56is 454 tons.
15:58Because of the skipped columns,
16:00all of these braces
16:01carry the same gravity load,
16:03just 340 tons
16:04from the eight stories above.
16:07The gravity load
16:08builds up in the center column,
16:09not in the braces.
16:11Which means
16:12there are 114 tons
16:14of tension in this brace.
16:16If each bolt
16:17can withstand around 28 tons,
16:19that would require four bolts.
16:21The original calculations
16:23said just four bolts were enough.
16:25So that was all they used.
16:28But when he added quartering winds,
16:30LeMessure's calculations
16:31showed there were some braces
16:32that needed far more bolts.
16:34At this particular part
16:36of the building,
16:37which I can show you
16:38on my calculations,
16:39is right about here.
16:42And Bill LeMessure
16:42talked about the 30th floor.
16:44I always wondered,
16:45why was it the 30th floor?
16:47The 40% increase
16:48from quartering winds
16:49means that this brace
16:50has a wind load
16:51of 635 tons.
16:53The tension in the brace
16:54is now 295 tons,
16:57over double
16:58the original calculation.
16:59So these braces
17:01actually need around 10 bolts,
17:03not four.
17:04But then it turned out
17:05they had done something else.
17:07LeMessure's firm
17:08considered the braces
17:09to be minor structural elements.
17:11They didn't use
17:11the right factor of safety
17:12to calculate
17:13the number of bolts.
17:14They should have
17:15overestimated the tension
17:16in the brace
17:17by underestimating
17:18the gravity load.
17:19With only 75%
17:21of the gravity load,
17:22the tension in the beam
17:23is now 380 tons.
17:25So they really needed
17:2614 bolts,
17:27but they used
17:28only four.
17:30I thought,
17:31this thing
17:31is in real trouble.
17:34Imagine, you know,
17:35what Bill LeMessure
17:35was thinking
17:36at that moment.
17:37You see that number
17:39and you're like,
17:40oh my god,
17:41this is serious.
17:42It's really serious.
17:43LeMessure was starting
17:44to panic.
17:46He didn't want
17:46to rush to conclusions,
17:48so he flew to Canada
17:49to check his calculations
17:50with Alan Davenport
17:51at the boundary layer
17:52wind tunnel.
17:53After running more tests,
17:54they found that it was
17:55even worse
17:56than LeMessure thought.
17:59The estimated 40%
18:00increase in stress
18:01was technically correct,
18:03but LeMessure
18:03made his calculations
18:04assuming the building
18:05wasn't moving.
18:06This is called
18:07static conditions.
18:09But the wind tunnel
18:09gave LeMessure
18:10a dynamic analysis,
18:12how the forces change
18:13when the building
18:14is moving around.
18:15To LeMessure's horror,
18:17the wind tunnel analysis
18:18showed that the stresses
18:19could increase up to 60%
18:21more than originally anticipated.
18:25LeMessure squirreled
18:26himself away in Maine
18:27and worked through the data
18:28from the wind tunnel again,
18:29joint by joint,
18:30on every floor.
18:32The weakest joints
18:33were at the building's
18:3330th floor.
18:35If those failed,
18:36the entire building
18:37would fall.
18:39But what were the chances
18:40that a storm strong enough
18:41to topple the building
18:42would pass through
18:43New York City?
18:45LeMessure dug through
18:46the historical weather reports.
18:49On average,
18:49a storm strong enough
18:50to tear the building apart
18:52occurred every 67 years.
18:54But only if the
18:55tuned mass damper
18:56was working.
18:57If a storm knocked out power,
18:59then even 110 km per hour winds
19:02blowing for just 5 minutes
19:03would collapse the building.
19:06In any given year,
19:07the chance of a storm
19:08that size happening
19:09was 1 in 16.
19:11Just one year before
19:13Citicorp was completed,
19:14wind gusts of 110 km per hour
19:16roared through New York City
19:18as Hurricane Bell
19:19passed through.
19:21What do you think
19:22this moment was like
19:23for LeMessure
19:24when he ran these calculations?
19:26Oh, it must have been devastating.
19:28I mean, it just must have been...
19:30I can't imagine the fear.
19:32I can't imagine the feelings.
19:33I mean, like,
19:34it just must have been...
19:37it just must have been...
19:37truly a moment
19:39he never thought
19:40he would live through.
19:42That storm was going to fall down
19:43in my lifetime.
19:45And since this was July,
19:48it could fall down
19:49the summer of 1978.
19:51LeMessure needed to decide
19:53and decide fast.
19:54But revealing this mistake
19:56could mean lawsuits,
19:57bankruptcy,
19:57and professional ruin.
19:59He could stay silent.
20:00Only Davenport knew
20:01and he wouldn't reveal anything
20:03or he could entirely disappear.
20:05In a later interview,
20:06he admitted,
20:07I did say to myself,
20:08I could drive down
20:09the main turnpike
20:10at 100 miles an hour
20:11and deliberately drive
20:12into a bridge abutment.
20:14That would be the end
20:15and all of this would go away.
20:17I thought about that.
20:20But there was a 1 in 16 chance
20:23of collapse that very fall.
20:25With thousands of lives at risk,
20:27there was never any other choice
20:29but to act.
20:31After speaking to a few lawyers
20:33and other engineering experts,
20:35LeMessure told the architect Stubbins
20:36and together,
20:37they informed Citicorp's chairman,
20:39Walter Riston.
20:41Within hours of that meeting,
20:42LeMessure acquired emergency generators
20:44for the tuned mass damper.
20:46The TMD was originally designed
20:47to stabilize any swaying for comfort,
20:50but now it became the crutch
20:51that the tower leaned on.
20:53LeMessure pinned all his hopes on it.
20:55He called the confidential repair plan
20:58Project Pandora,
20:59but that sounded ominous.
21:01So he came up with
21:02the special engineering review
21:04of events nobody envisioned,
21:07or Project Serene for short.
21:09Each night, welders would enter the building
21:12after everyone left,
21:13rip off the sheetrock
21:14around the chevron beams,
21:15and then weld two five-centimeter thick,
21:18two-meter long steel plates
21:19on each joint.
21:21Like band-aids,
21:22literally band-aids
21:23on both sides of these joints.
21:25After, they'd replace the wall
21:26and clean everything up
21:28before the office workers
21:29came back the next morning.
21:31They needed to weld over 200 joints,
21:34and LeMessure ranked them by importance,
21:36starting with the ones on the 30th floor.
21:38But the repairs wouldn't be completed
21:40before hurricane season,
21:42so Citicorp worked with the Red Cross
21:43to develop a 10-block evacuation plan.
21:46Like, how many people were at risk in the building,
21:49and if it fell,
21:49would it affect other buildings?
21:51Like, were there chances of it
21:52leading to something more disastrous?
21:54Absolutely.
21:55This would have toppled,
21:56and it would have toppled
21:58into another building,
22:00which would have toppled
22:01into another building,
22:02which would have continued
22:04a horrific process.
22:06So it was untold
22:08what the ultimate effects
22:10could have been.
22:11I mean, like,
22:11just the evacuation plans
22:12were how many people?
22:14Thousands.
22:15The building itself housed thousands,
22:17and then the residents
22:18and the businesses
22:19surrounding the building,
22:21it was into the thousands.
22:23Despite the risk,
22:25they decided not to tell the public
22:26or even the office workers
22:28in the building.
22:29No one wanted a mass panic.
22:31Instead, they fitted strain gauges
22:33on important structural members.
22:35The gauges monitored the skyscrapers
22:37every bend and twist
22:38from a comm center
22:39eight blocks away.
22:41At least,
22:42that would give them
22:42a little bit of warning.
22:44But this plan required
22:45new telephone lines,
22:46and the phone company
22:47wouldn't get around
22:48to doing this for months.
22:50So Citicorp's chairman
22:51immediately called
22:52AT&T's president,
22:53and the lines were installed
22:54the next morning.
22:56Now, you might not be able
22:57to install emergency telephone lines
22:58at a whim,
22:59but you can still stay connected
23:00no matter what.
23:05It's probably not that important.
23:07Henry?
23:08Can you hear me?
23:09Hello?
23:10Team Veritasium travels
23:11all over the globe
23:12for our videos.
23:12We traveled here to New York
23:14to visit the Citicorp Center,
23:15and there's one
23:16really annoying problem.
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23:18with the rest of the team
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23:22find a local SIM card
23:23and hope it actually works,
23:25or search around
23:25for public Wi-Fi
23:26that might not be
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23:52and be able to do
23:53the important things
23:54like access maps,
23:55book a car,
23:56or call your boss.
23:57So,
23:57if you've got travel plans
23:59coming up,
23:59scan this QR code
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24:13Thank you, Salie,
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24:15and now,
24:15back to Project Serene.
24:20I mean,
24:21it's probably like this.
24:23But even though
24:24Le Measure tried
24:25to keep Project Serene
24:26under wraps,
24:27people started asking questions.
24:30On August 8th,
24:31Citicorp released
24:32a statement
24:32about the repairs.
24:34No, we had to cook up
24:35a line of bull,
24:36I'll tell you.
24:37And white lies,
24:38at this point,
24:38are entirely moral.
24:41You don't want
24:42to spread terror
24:43in the community
24:44to people
24:45that don't need
24:46to be terrorized.
24:47We were terrorized,
24:48no question about that.
24:49Several newspapers
24:50reported on it,
24:51but they didn't have
24:52the details.
24:53Then,
24:54Le Measure got a message.
24:56The New York Times
24:56was trying to reach him.
24:58If he didn't respond,
24:59they would know
25:00something was up.
25:01So,
25:02I mixed a martini
25:04for myself.
25:05And it's
25:06one minute past six.
25:07I dialed
25:08the New York Times.
25:09I pick it up,
25:10the phone.
25:11They pick up the phone.
25:12It's a tape recorder
25:13saying,
25:14the New York Times
25:15has gone on strike
25:16as of six o'clock.
25:19Not only did
25:20the New York Times
25:21go on strike,
25:22but all the newspapers
25:23in New York
25:24went on strike
25:25until October.
25:27So,
25:27we had a press blackout.
25:29and that was
25:29the greatest thing
25:30that ever happened.
25:33The press was
25:34off their back
25:35and the weather
25:36was beautiful.
25:37The repair work
25:37continued smoothly.
25:39But late August
25:41brought the news
25:41everyone had been dreading.
25:44Hurricane Ella
25:45starts brewing
25:46in the Caribbean
25:47and this is
25:50the one storm
25:51that they're nervous about.
25:53The repairs were
25:54halfway done by now.
25:55I think it was
25:56a one in 200 year
25:58storm
25:59that it could withstand
26:00but the measure
26:02wasn't taking chances
26:03because we didn't know
26:04the intensity of the storm
26:05and this was a strong storm.
26:07So,
26:07there was a chance?
26:09There was absolutely
26:09a chance
26:10and they had to prepare
26:11for that chance.
26:14By Friday,
26:15September 1st,
26:16Ella was making her way
26:17toward New York
26:18with winds reaching
26:19200 kilometers per hour.
26:21City officials
26:22braced to start
26:23the evacuation.
26:24Police would go
26:25door to door
26:25to get everyone out
26:26within a 10 block radius.
26:29For 24 tense hours,
26:31Ella stalled
26:32around North Carolina.
26:34Like LeMessure said,
26:35we were sweating blood.
26:38But sometime in the night,
26:39Hurricane Ella
26:40veered off into the sea
26:41at the last minute.
26:42It intensified
26:43and hit Canada
26:44with peak winds
26:45of 225 kilometers per hour.
26:49But City Corp
26:50was safe.
26:53LeMessure described
26:54that next morning
26:55in New York
26:55as the most beautiful day
26:57that the world's ever seen.
26:59They completed the repairs
27:01in October,
27:02just six weeks
27:03after LeMessure told City Corp.
27:05Now,
27:06the building,
27:07according to LeMessure,
27:08can withstand
27:08a one in 1,000 storm.
27:11The repairs cost between
27:12four and five million dollars,
27:14but LeMessure argued
27:15that City Corp approved
27:16an earlier building design
27:18that cost five to six million more,
27:20so they were willing
27:21to spend that much
27:21on the skyscraper anyway.
27:25And for almost two decades,
27:27the secret was confined
27:28to a small inner circle.
27:30But in 1995,
27:32the New Yorker
27:33finally brought Project Serene
27:34into the light.
27:36Far from being vilified,
27:37LeMessure was praised
27:38for owning up to his mistake
27:40and fixing the issue
27:41as soon as possible.
27:42After the article,
27:44New York updated
27:44the building code
27:45to require quartering wind calculations.
27:48And since that first damper
27:49in City Corp,
27:50TMDs have spread
27:51across the globe,
27:52allowing architects
27:53to push skyscrapers
27:54taller and slimmer.
27:56It's the first tall building
27:57in the world
27:58ever built
27:58with mechanical help
28:00to make the structure work.
28:02That's remarkable.
28:03Incidentally,
28:04that has been now copied
28:05a hundred times in Japan.
28:06This is ubiquitous,
28:07and when I go to Japan,
28:09I'm treated like a tin god
28:10because I'm the father
28:11of the tuned mass damper.
28:12I said, really?
28:13Of the 20 tallest buildings
28:15in the world,
28:16six include a tuned mass damper.
28:18And they're especially
28:19critical in typhoon
28:20or earthquake-prone regions.
28:22For example,
28:23Taipei 101
28:23has a massive
28:25660-ton pendulum
28:26that stabilizes the building.
28:29It can withstand
28:29up to 200 km per hour winds
28:32and earthquakes
28:33with magnitudes
28:33over 6.8.
28:35But the legacy
28:36of this building
28:37is still steeped
28:38in controversy.
28:39First,
28:40who was the mysterious student
28:42that started it all?
28:44I think it was
28:45spring of 1978.
28:47There's a student
28:48at Princeton,
28:49an undergraduate student
28:51by the name of
28:51Diane Hartley,
28:53and she's studying
28:54structural engineering.
28:56It was time for her
28:57to consider a senior thesis,
28:59and they decided
29:00that a study
29:02of the new
29:03Citicorp tower
29:04would be wonderful.
29:05It's a remarkable thesis.
29:06It contains a lot
29:07of the original
29:08engineering calculations
29:09by the engineers.
29:10She's looking
29:11through the documentation,
29:15where did they consider
29:15quartering winds?
29:17And she's not seeing it.
29:18I must be wrong,
29:20she says.
29:20She's just
29:21an undergraduate student,
29:22and you guys
29:23are award-winning
29:24structural engineers.
29:26The engineer
29:27explains to Diane Hartley,
29:29quartering winds
29:30are not a factor
29:32in this building.
29:33So she's satisfied.
29:35She graduates.
29:36That's it.
29:36Doesn't think
29:37about it again.
29:38But a year
29:39after the New Yorker article,
29:41the BBC released
29:42a documentary
29:42on the crisis.
29:44And so she
29:44was holding her baby,
29:46and she turned
29:47on the television,
29:49and lo and behold,
29:51she heard them
29:51reference a conversation
29:53with a student,
29:56an engineering student
29:57from New Jersey,
29:58reaching out
29:59to LeMessur,
30:00and she said,
30:01I almost dropped
30:01my baby.
30:03And then,
30:03so she just assumed,
30:04for years afterwards,
30:06she assumed
30:06that it wasn't me,
30:08because I didn't
30:09speak to LeMessur.
30:10But then in 2003,
30:11her thesis advisor
30:12told Diane
30:13that he checked
30:14all the other
30:15New Jersey engineering
30:16and architecture programs,
30:17and no one else
30:18was working on a project
30:19about Citicorp in 1978.
30:22She was the only one.
30:24She never spoke
30:25to LeMessur personally.
30:26She never claimed
30:27to speak to LeMessur personally.
30:29The assumption was
30:30that either
30:31LeMessur was mistaken,
30:33and that it was
30:34Diane Hartley
30:35who made the call.
30:36It was a female.
30:36Or, more likely,
30:38that LeMessur
30:39was basically tipped off
30:41by his New York engineers.
30:44Then, in 2011,
30:45a man named
30:46Lee DeKeralis
30:47came forward.
30:48And the phone call,
30:49as we understand it,
30:50came from a student
30:51at the New Jersey
30:52Institute of Technology.
30:53His name is Lee DeKeralis.
30:54He's not asking for money.
30:56He's not asking for fame
30:58or glory.
30:58He's just saying,
30:59this is interesting,
31:00and I'm the guy
31:01who made this call.
31:03And he said,
31:03yeah, I had a conversation
31:05with Bill LeMessur,
31:05and he pretty much lined up
31:07with what LeMessur
31:08himself said.
31:10Sadly,
31:10LeMessur passed away
31:11in 2007
31:12before he could confirm
31:13the student's identity.
31:16Believe it or not,
31:1740 years later,
31:18there's still,
31:19I learned,
31:20a lot of raw feeling
31:21still on this.
31:23People aren't anxious
31:24to talk about this,
31:25especially people
31:26that were involved in it.
31:28Even people
31:29that weren't involved in it,
31:30but were tangentially
31:32involved in it.
31:33We reached out
31:33to LeMessur Associates,
31:34and they refused
31:35to respond to our request.
31:36You'd think that they would,
31:38the namesake for their company
31:39stood up and did the right thing,
31:42but I don't think
31:42they want to be associated
31:43with mistakes.
31:45Their project description
31:46for Citicorp
31:47doesn't even mention the repairs.
31:49The building was sold
31:49to Boston Properties in 2001,
31:51who renamed it
31:52601 Lexington.
31:55They also didn't respond
31:56to our request for comment
31:57and refused to let us film
31:59inside the building.
32:00Further questions arose
32:02in 2021 with a new study
32:04from the National Institute
32:05of Standards and Technology.
32:07They wanted to see
32:07if quartering winds
32:08were more demanding
32:09for a building like Citicorp.
32:11Although they did conclude
32:12that the pressure
32:12from perpendicular winds
32:14was greater,
32:15their analysis didn't include
32:16any internal structure
32:17specific to Citicorp.
32:19As for LeMessur,
32:20the engineering field
32:21still regards his actions
32:22as upstanding,
32:23and the Citicorp case
32:24is taught all over the world
32:25as a case of good
32:26engineering ethics.
32:27In fact,
32:28in my own engineering ethics course,
32:29I learned about
32:30the Citicorp building.
32:31Every structural engineer
32:32experiences this.
32:33When you actually feel
32:35the weight of the responsibility,
32:37you're saying,
32:38based on my engineering,
32:39that building is going to stand up.
32:40Nobody else worries about it.
32:42And so if you think
32:42about the emotional pressure
32:44that Bill LeMessur was under,
32:46and then needing to come back
32:47and do something about it
32:48and to mobilize
32:49and to hold that,
32:50during this entire process,
32:52it's truly a remarkable story.
32:55I mean, I can't imagine it.
32:56I can't imagine it.
32:58I said, look,
32:59if you got a license
33:00from the state
33:01and a certification
33:02for University First,
33:04and now you're going to use
33:05that license
33:05to hold yourself out
33:06as a professional,
33:08you have a responsibility
33:09beyond yourself.
33:11If you see something
33:12that is a social risk,
33:14good heavens,
33:14this thing would kill a thousand.
33:16You must do something.
33:18You must do something.
33:19You must do something.
33:28You must do something.
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