WEBVTT
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Yeah, I'd like to go ahead and start our
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evening's lecture. My name is Finley Charney. I'm
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a professor of the Department of Civil Environmental Engineering
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and my specialty in structural engineering. And it's my
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pleasure to have hosted these CELES lectures over
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the past 10 years ago. CELES stands for the
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Center for Extreme Load Effects on Structures. Principally we
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look at wind and seismic loads, more seismic in the
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past. Recently. I think we're getting back into the
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wind area for a variety of reasons. I apologize
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at this slide like that. We transferred the slide
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of the black text, which used to be like
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, you can't read it very well, but this
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is just a list of some of the sponsors,
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some people who have actually contributed two oh center over
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the past several years and who helped fund this lecture
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. We've been also very fortunate over the years to
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have and including today some of the most distinguished structural
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engineers. It's not just in the United States in
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the world, lectures present lectures to us here in
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this lecture suit and some of these names should be
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very recognizable to you. Very riffles. Irwin john
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Rose, thank you baker, David. Goodyear.
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Asan Corinne has given us fascinating lectures over the years
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, mostly about building. Somehow, this has been
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a tall, building oriented presentation in the past.
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We did go horizontal with David a few years ago
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we talked about hoover dam five past. And so
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this year we're going to actually go vertical again and
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robert sent with thornton thomas city in Chicago Is going
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to tell us about this new one km tall kingdom
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tower. So if you take Bill baker's burst cloth
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e, the empire statement went on top of it
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. Then you have this building kilometer tall. It's
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pretty amazing. Um, this, let me give
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you a little introduction uh, about robert. After
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our chatting this afternoon, robert and I realized we've
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known each other for about 15 years back when we're
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both more active than sc, which has a committee
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on paul buildings. We're both a member of that
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committee at the same time. Uh Mr Sent is
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currently a principal in the Chicago office of thomas city
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and as the firm white director of structural engineering for
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new buildings, They have 30 years of combined experience
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starting out skin borrowings, Amero and for the last
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seven years of Thomas A and has been involved in
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the structural design. Obviously a very important buildings.
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Guggenheim Museum in Spain trump International Hotel and Tower on
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Chicago and the people in power will be talking about
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here. He is a fellow of the American Society
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of Civil Engineers and the International Association of Bridge Construction
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. Okay, uh, he received as M.
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S. From Northwestern University, mm. MSC E
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. At Technology 1934. So with that I'd like
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to welcome robert for I'm sure will be a very
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interesting presentation. We also have. Okay. Mhm
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. Okay. He's like me all metal he gets
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credit for. Well, thank you. It's an
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honor to be invited to come here today from Chicago
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, beautiful weather outside. And I'd like to give
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you a few details of a very important project for
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our firm that we've been working on for actually over
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five years now. A few sort of technical information
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in terms of the team thorn thomas said er the
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structural engineers for the project. The architect is Adrian
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smith and Gordon Gill a couple of Old colleagues of
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mine from Skidmore owings and Merrill. They left the
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firm in 2006, I left the firm in 2007
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. Um The contractor for the project is the Saudi
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bin laden group. The we won the competition all
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the way back in June of 2009 and we,
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after a few stops and starts, we finished the
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design drawings just recently about a little over a year
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ago in August 2013. Um All the design for
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the tower is two american codes and the concrete reinforced
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concrete design is to a ci 3 18. Uh
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This is the Rogue's gallery of most of the tall
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buildings. Most of these have actually been completed at
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this time, but this was the council's idea of
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what the tall buildings would look like in 2020 which
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is not that far away, it's only six years
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down the road, They call anything over 600 m
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super tall. Uh and of course, the Kingdom
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Tower would be the tallest of all uh peeking just
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above. Uh one kilometer will be the first man
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made structure to reach one kilometer in height. So
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it's sort of the uh Alan bannister for those of
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you know the four minute mile. It's sort of
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the Alan bannister of tall buildings. But the tower
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is part of an overall master plan in the city
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of Jeddah in Saudi Arabia. So the idea is
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you build the tower and then you can have a
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lot of other buildings around it, residential buildings,
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even office towers. And it becomes part of a
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really an entire city in a lot of ways.
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Um Just some news, the picture you see there
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on the left is Prince uh Al walid. And
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if you follow the news, the prince is very
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famous actually. He's uh he's the fellow they call
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the Saudi Warren Buffett. He's the one that does
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buys all the stock in city core and other U
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. S. Properties, US companies. And he's
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his company is called Kingdom Holdings. He has two
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or three partners that are also contributing the funding for
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the project. This is a picture on site as
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piling was going on and if you look closely in
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the foreground you'll notice that this is actually one of
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our drawings here. This is a foundation plan from
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from thornton thomas et the picture on the right for
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those of you uh know your geometry. The project
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is in Jeddah in the kingdom of Saudi Arabia.
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It's right on the Red Sea. Um The site
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itself is just north of the air. This is
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the airport. So this is this is the Hajj
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terminal. This is where the people come from their
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pilgrimage. They go through the Hajj terminal in Jeddah
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as a sort of gateway to the holy cities of
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Mecca and Medina. And the site for the,
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for the tower is just north of the creek,
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north of the airport. And right now it's barren
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land. I'll show you a few pictures of that
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. Um, The tower is a mixed use but
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primarily residential. At the base of the tower.
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There will be a little bit of office space,
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very little actually only 10 floors. Uh and then
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there's a four seasons hotel just above that. And
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then the rest of it is all residential. It's
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basically condominiums from there on Up to about 670 or
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80 m. It's habit id and the rest of
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it is actually avoid, I'll get to that in
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a minute. It's, the tower will be not
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only uh the tallest building in the world, but
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also the most, one of the most slender.
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And we measure for these tall buildings, the slender
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nous as the height divided by the least dimension at
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the base. and for this building, that number
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is about 12-1. Just to give you a little
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bit of perspective on that. The Sears Tower and
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the Hancock building in Chicago, where I'm from.
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The aspect ratio on those buildings is about six or
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7-1 maybe, maybe Sears tower is almost eight.
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So you can see that buildings nowadays are getting taller
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, but they're also getting more slender than they were
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30 or 40 years ago. The tower has two
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systems that are linked their, their distinctly different systems
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, but they're fundamentally link. There's not a discontinuity
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in the systems For the bottom 2/3 of the building
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, essentially a bearing wall building. And I'll get
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to exactly what that means in a minute. But
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and above that is the silo, which is basically
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a closed concrete tube without any windows whatsoever in it
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. This is what this system looks like in concept
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. It's um basically all walls. I tell my
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colleagues when they ask about the system, they said
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, you know, how big are the columns and
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I say we don't have any columns, it's all
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walls, there's no uh inside and outside, there's
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no perimeter columns and inside core, like most tall
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buildings, everything is connected together through coupling beams,
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all pieces of wall contribute in the system to resisting
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the gravity loads and the lateral loads. There's no
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outriggers, lot of the tall buildings and super tall
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buildings. In fact, almost all of them,
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including Burj Khalifa in Dubai have outriggers that extend from
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walls to other columns. There are no outriggers in
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Kingdom Tower, there are no column transfers. There
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are no wall transfers, walls simply go up and
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when they're no longer needed due to the tapering of
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the tower, they drop off. The system in
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concept is very simple. It's it's a building was
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made to be built. There was no uh everything
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we did in the planning, architectural and structurally was
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to make it simple to build. Now you've seen
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the tapering of the tower. What uh just to
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be clear about the geometry? There's it's a 33
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winged tower. Three wings to it. Each of
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the wings tapers. Those three tapers for the three
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individual wings are slightly different but but for a single
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wing it's a single taper basically one angle from the
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top of the foundation all the way to the top
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of the building. But because of the three wings
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taper at slightly different angles, they reached the top
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at different elevations. And that gives you the sort
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of the characteristic architectural top of the building. So
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it's very simple, very, very easy to build
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, simple geometry from that standpoint. That's what the
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floor plan looks like. Ah there's no spaniel beams
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, All flat plate construction, 250, about a
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10 in reinforced concrete flat plate, conventionally reinforced all
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walls and coupling beams. The the spacing between the
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we call them the thin walls. This this spacing
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in between here, that's about nine m and that's
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important for the planning. So this is what the
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architects, what they ended up with. Again,
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this is primarily a residential building. This system would
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not work nearly as well for an office use because
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what happens, it tends to compartmentalize the floor plate
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with these, these transverse walls. But this is
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what happens. You basically take your elevator in the
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center of the tower. These are all the elevators
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. And because it's residential, there's far fewer elevators
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that there would be in an office tower. You
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come out, you come down the corridor and that
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corridor has structural walls on either side of it and
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then you call me and then you turn left or
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right through a doorway into your into your unit,
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All of the fire stairs. And there are three
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at the end of each wing are completely encircled by
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concrete walls. So that's the fundamentals of how the
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by the building is planned structurally and architecturally. This
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is what a unit looks like. And you can
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see that yes, the thin walls are in some
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of the units, but the layout's worked very well
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, the corner is open and uh you can see
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how the kitchens and the bathrooms layout amongst all the
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structure. It's actually works quite well for residential type
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of use. Now I mentioned that there's really two
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systems that are linked. You have the system of
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walls and coupling beams that go up wherever the floors
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are inhabited by tenants in the building. And then
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they come up to about the 2/3 and then the
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rest of the building is a concrete silo, it's
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really open void, it's truly, there's very there's
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no windows in it all the way to the top
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of the building. And those two systems Are actually
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linked and they're linked at a four metre thick sky
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raft. And that's that's this element here. So
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what happens is that the walls of the floors that
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the last walls that are tilting, they become closer
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and closer and closer to the central triangular core and
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then finally they almost touch and there's a transition to
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the top uh aspire, what we call, that's
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made of just reinforced concrete walls above. So there's
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no dis continuity this wall that you see here.
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That's the spire. That's a, that's a single
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plane, a tilted plane that goes all the way
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to the top of the foundation without any kinks or
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interruptions whatsoever. For those of you who like your
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history of tall buildings and history of structural engineering,
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certainly, this tower came on the heels of the
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Burj Khalifa and Dubai, we won the competition.
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The organizer of the competition wanted to use the Berge
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as a way of reducing risk. So a system
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that would be similar to the Berge, but maybe
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improve upon it a little bit and change a few
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things that didn't work quite as well on that tower
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when we did this one. But if you look
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at this is a picture of three buildings cut at
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basically foundation level. So this is at the bottom
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of the building, what they look like Kingdom Tower
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Burj Khalifa, you see the similarities between our tower
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and the bird. You have a central, this
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is a hex core. This we have a triangle
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, you have the corridor walls, you have the
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thin walls. These are columns that we don't have
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, we replaced those with the, with the end
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walls in the stairs. But I think this,
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that there's there's some fundamental differences. This this building
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did have outriggers, uh it did have a steel
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part of the upper level, whereas we have concrete
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and I think if you really wanted to go back
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to the bearing wall system for very tall buildings,
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you would look at the CN tower in Toronto,
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that's this one, that's not a building, it's
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an observation tower, but look how similar they are
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. Now, this is obviously CN tower isn't one
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kilometer tall, but it's got a central, it's
268
00:15:52.029 --> 00:15:54.240 A:middle L:90%
got very thick walls including a very to meter thick
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wall at the extremity of the floor plate, just
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like Kingdom Tower. It's got basically compartments that are
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created by these cross walls. Very, very similar
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system. There's no transfers in this building either.
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Basically the walls just tilt at a constant angle from
274
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top to bottom. Very, very similar system.
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00:16:15.129 --> 00:16:18.149 A:middle L:90%
This was done in the early 1970s. So the
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00:16:18.149 --> 00:16:21.269 A:middle L:90%
system has been around a long time. The Burj
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Khalifa was a very excellent structure but it wasn't necessarily
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new. Okay, so there's a hierarchy in the
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00:16:32.419 --> 00:16:34.529 A:middle L:90%
walls, the most important of all are the ones
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that are furthest from the neutral axis from the center
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of the building. And those are the end walls
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00:16:40.470 --> 00:16:41.700 A:middle L:90%
. These are the these are the only walls that
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slope. Everything else is vertical. Okay, at
284
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the base of the tower, those are 1.2 m
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00:16:48.419 --> 00:16:52.440 A:middle L:90%
thick. So about I guess about 4, 4.5
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00:16:52.440 --> 00:16:55.159 A:middle L:90%
or five ft thick. No more than that at
287
00:16:55.159 --> 00:16:59.470 A:middle L:90%
the at the base of the tower and they continue
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up And they reach about 500. By the time
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00:17:02.830 --> 00:17:06.579 A:middle L:90%
you get up into the spire, the second most
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00:17:06.579 --> 00:17:10.849 A:middle L:90%
important walls are the ones along the corridor. Those
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00:17:10.849 --> 00:17:12.970 A:middle L:90%
are about a meter thick at the base. Those
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00:17:12.970 --> 00:17:17.359 A:middle L:90%
are attached to the, to the end walls through
293
00:17:17.359 --> 00:17:22.289 A:middle L:90%
the stair towers. Um Sorry, just going back
294
00:17:22.289 --> 00:17:23.349 A:middle L:90%
a minute. Those are the ones that have more
295
00:17:23.349 --> 00:17:26.000 A:middle L:90%
coupling beams. The end walls have no coupling beams
296
00:17:26.130 --> 00:17:27.980 A:middle L:90%
. This is a solid wall, no coupling beams
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00:17:29.190 --> 00:17:30.420 A:middle L:90%
. The corridor walls are the ones that are uh
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you know, punctured with coupling beams at every floor
299
00:17:33.940 --> 00:17:36.940 A:middle L:90%
so people can get into their units. Those coupling
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00:17:36.940 --> 00:17:44.130 A:middle L:90%
beams are 1.5 m deep in general. The third
301
00:17:44.130 --> 00:17:45.700 A:middle L:90%
is the fin walls. I would call those more
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stabilizers. They're stabilizing the corridor and end wall systems
303
00:17:49.920 --> 00:17:56.509 A:middle L:90%
laterally. They are, They reach 8 50 thick
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00:17:56.519 --> 00:17:59.640 A:middle L:90%
at the base of the tower. They also have
305
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coupling beams so that people can go in between the
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compartment als and then finally, is the triangular core
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. The triangular core is very critical for the two
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00:18:08.500 --> 00:18:11.809 A:middle L:90%
orginal stiffness of the building. A lot of the
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00:18:11.809 --> 00:18:15.089 A:middle L:90%
torso resistance is being generated through the triangular core.
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It's a closed shape, it has very few openings
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in it. It houses as I mentioned before,
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all, all of the elevators for the tower.
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Now, one of the things that was very important
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00:18:29.779 --> 00:18:33.210 A:middle L:90%
in the planning that caused almost World War Three with
315
00:18:33.210 --> 00:18:37.359 A:middle L:90%
the architects was the the the alignment of the walls
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through the corridors. We had to really impose some
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pretty draconian measures with the architects. They had to
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line up and the reason they had to line up
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is because the the flow through here is very dependent
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00:18:51.670 --> 00:18:53.099 A:middle L:90%
on the pattern, not just the gravity load flow
321
00:18:53.099 --> 00:18:55.910 A:middle L:90%
, which is important enough, but also the wind
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loads. If you start moving these doors around,
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00:18:59.450 --> 00:19:02.259 A:middle L:90%
you're gonna be cutting off the flow. So what
324
00:19:02.259 --> 00:19:03.480 A:middle L:90%
we did is working with the architects, we actually
325
00:19:03.480 --> 00:19:08.210 A:middle L:90%
plotted the entire elevation of the building on paper And
326
00:19:08.210 --> 00:19:11.130 A:middle L:90%
it was about 20 ft long and we put it
327
00:19:11.140 --> 00:19:12.940 A:middle L:90%
put it in the office there in Chicago. We
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00:19:12.950 --> 00:19:15.660 A:middle L:90%
we taped it all together and and told the architects
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00:19:15.660 --> 00:19:18.680 A:middle L:90%
to come over and we we would stand next to
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it and say you can't have that when you can't
331
00:19:19.269 --> 00:19:22.369 A:middle L:90%
have that one. And and by doing that I
332
00:19:22.369 --> 00:19:23.430 A:middle L:90%
think they kind of got the idea of what we
333
00:19:23.430 --> 00:19:26.849 A:middle L:90%
were trying to achieve. Yes, there's a few
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00:19:26.859 --> 00:19:29.529 A:middle L:90%
few outliers, you know, this is a this
335
00:19:29.529 --> 00:19:32.660 A:middle L:90%
is a special fire exit for that particular floor,
336
00:19:32.660 --> 00:19:33.869 A:middle L:90%
but generally speaking, we were able to line them
337
00:19:33.869 --> 00:19:38.130 A:middle L:90%
up very, very carefully and very, not just
338
00:19:38.130 --> 00:19:41.960 A:middle L:90%
structurally important, but also from a construction standpoint,
339
00:19:41.970 --> 00:19:44.740 A:middle L:90%
the more you start moving things around, the formwork
340
00:19:44.740 --> 00:19:45.839 A:middle L:90%
system has to be adjusted for those as well.
341
00:19:45.849 --> 00:19:48.859 A:middle L:90%
So once again, the design was to be built
342
00:19:52.839 --> 00:19:56.150 A:middle L:90%
in terms of materials. Um the concrete strength is
343
00:19:56.150 --> 00:19:59.450 A:middle L:90%
not as high as you might think. It's about
344
00:19:59.460 --> 00:20:02.670 A:middle L:90%
85 mega pascal uh cylinder strength, which is about
345
00:20:02.670 --> 00:20:07.130 A:middle L:90%
12,500 which is at least in the United States,
346
00:20:07.130 --> 00:20:08.549 A:middle L:90%
is its high strength concrete, no doubt about it
347
00:20:08.559 --> 00:20:11.269 A:middle L:90%
, but we certainly know of higher strengths uh you
348
00:20:11.269 --> 00:20:14.779 A:middle L:90%
know, that have been used, this was set
349
00:20:14.789 --> 00:20:17.500 A:middle L:90%
not so much that they couldn't produce higher strength concrete
350
00:20:17.500 --> 00:20:19.859 A:middle L:90%
. The tower would have benefited greatly from higher strength
351
00:20:19.859 --> 00:20:22.710 A:middle L:90%
concrete. I think if I had my choice,
352
00:20:22.990 --> 00:20:25.359 A:middle L:90%
the strength would have been 15 or 16 K.
353
00:20:25.359 --> 00:20:26.819 A:middle L:90%
C. Concrete. And the reason I say that
354
00:20:26.829 --> 00:20:29.210 A:middle L:90%
is at the bottom of the tower, there's a
355
00:20:29.210 --> 00:20:30.250 A:middle L:90%
lot of reinforcement to make up for the lack of
356
00:20:30.250 --> 00:20:33.079 A:middle L:90%
concrete strength. So if we had higher strength concrete
357
00:20:33.079 --> 00:20:37.059 A:middle L:90%
we could have reduced the rebar which would have helped
358
00:20:37.059 --> 00:20:40.069 A:middle L:90%
the construction quite a bit. But the reason It's
359
00:20:40.069 --> 00:20:42.849 A:middle L:90%
only 12,500 is they could do higher but not in
360
00:20:42.849 --> 00:20:45.539 A:middle L:90%
the volumes that we need. And there's a lot
361
00:20:45.539 --> 00:20:48.029 A:middle L:90%
of concrete in this building and they, from a
362
00:20:48.039 --> 00:20:51.339 A:middle L:90%
quality standpoint and the quantity that's about as high as
363
00:20:51.339 --> 00:20:53.289 A:middle L:90%
they thought they could get rebar, were using some
364
00:20:53.289 --> 00:20:56.799 A:middle L:90%
75 Ks. I bar at the at the bottom
365
00:20:56.799 --> 00:20:59.930 A:middle L:90%
of the tower which is readily available in the Middle
366
00:20:59.930 --> 00:21:00.930 A:middle L:90%
East. But the vast majority of it is just
367
00:21:00.930 --> 00:21:08.009 A:middle L:90%
normal 60 Ks I reinforcement. This is a mixed
368
00:21:08.009 --> 00:21:11.299 A:middle L:90%
design. Just give you an idea for the 85
369
00:21:11.299 --> 00:21:14.670 A:middle L:90%
MPA concrete. It's being adjusted a little bit.
370
00:21:15.039 --> 00:21:18.279 A:middle L:90%
They don't have slag in the kingdom but they do
371
00:21:18.279 --> 00:21:22.259 A:middle L:90%
have fly ash. So fa is fly ash,
372
00:21:22.640 --> 00:21:26.839 A:middle L:90%
It's got a fairly high content of micro silica silica
373
00:21:26.839 --> 00:21:30.529 A:middle L:90%
fume and ordinary Portland cement. And you can see
374
00:21:30.529 --> 00:21:32.960 A:middle L:90%
the other characteristics. I would say that this mix
375
00:21:32.960 --> 00:21:36.829 A:middle L:90%
design because it has the polycom box lit uh It's
376
00:21:36.829 --> 00:21:41.359 A:middle L:90%
essentially near self consolidating concrete and that's because there's a
377
00:21:41.359 --> 00:21:45.269 A:middle L:90%
lot of rebar congestion near the bottom. It's also
378
00:21:45.269 --> 00:21:47.980 A:middle L:90%
because it has to be pumped. So they're using
379
00:21:48.000 --> 00:21:52.460 A:middle L:90%
basically 10 3/8 aggregate because it has to be pumped
380
00:21:53.910 --> 00:21:56.019 A:middle L:90%
. The one thing about the concrete, these high
381
00:21:56.019 --> 00:21:59.970 A:middle L:90%
strength concrete that a lot of people don't realize is
382
00:21:59.970 --> 00:22:03.230 A:middle L:90%
they're, they're denser. Most of your calculations,
383
00:22:03.230 --> 00:22:04.710 A:middle L:90%
I'm sure using 100 and£45 per cubic foot for
384
00:22:04.710 --> 00:22:08.039 A:middle L:90%
your concrete density. This one is 1 49 not
385
00:22:08.059 --> 00:22:11.319 A:middle L:90%
including any rebar. So most of our calculations were
386
00:22:11.319 --> 00:22:15.789 A:middle L:90%
using 150 to£253 per cubic foot for the self
387
00:22:15.789 --> 00:22:22.819 A:middle L:90%
weight of the concrete elements. In terms of foundations
388
00:22:22.819 --> 00:22:26.069 A:middle L:90%
and geo technics. The uh, it's, it's
389
00:22:26.069 --> 00:22:30.039 A:middle L:90%
basically uh very competent rock, but not what I
390
00:22:30.039 --> 00:22:33.000 A:middle L:90%
would call bedrock. There's no layer that you want
391
00:22:33.000 --> 00:22:34.960 A:middle L:90%
to take a foundation down and sit it on bedrock
392
00:22:34.970 --> 00:22:40.089 A:middle L:90%
. It's basically starting with Coraline limestone. It's basically
393
00:22:40.089 --> 00:22:42.990 A:middle L:90%
the coral from the Red Sea that's been disintegrated over
394
00:22:42.990 --> 00:22:47.980 A:middle L:90%
the years and with basically cemented together with the moisture
395
00:22:47.980 --> 00:22:51.390 A:middle L:90%
in the ground. And then there's a couple of
396
00:22:51.400 --> 00:22:53.299 A:middle L:90%
very annoying layers of silt, stone and gravel,
397
00:22:53.319 --> 00:22:59.190 A:middle L:90%
which caused problem with piling and then actually weaker ground
398
00:22:59.190 --> 00:23:03.569 A:middle L:90%
below that than up above the strongest Materials are actually
399
00:23:03.569 --> 00:23:06.529 A:middle L:90%
near the surface, the top 50 m, but
400
00:23:06.529 --> 00:23:10.960 A:middle L:90%
basically types of limestone and sandstone is what you have
401
00:23:10.960 --> 00:23:17.170 A:middle L:90%
there for for this particular site. Now the foundation
402
00:23:17.170 --> 00:23:19.920 A:middle L:90%
system is, It's a matrix of bored piles,
403
00:23:19.920 --> 00:23:22.980 A:middle L:90%
basically the piles, there's 270 piles, they're all
404
00:23:22.980 --> 00:23:26.430 A:middle L:90%
in, they've all been constructed, they go to
405
00:23:26.430 --> 00:23:29.690 A:middle L:90%
various depths, the ones in the center of the
406
00:23:29.690 --> 00:23:33.269 A:middle L:90%
tower Go to a depth of 100 105 m,
407
00:23:33.279 --> 00:23:37.589 A:middle L:90%
so about 350 ft deep, The shorter ones go
408
00:23:37.589 --> 00:23:41.049 A:middle L:90%
to 45 m. The diameter is about 1.5 m
409
00:23:41.059 --> 00:23:45.170 A:middle L:90%
, a few 1.8 m diameter piles. So this
410
00:23:45.170 --> 00:23:48.319 A:middle L:90%
is a very common type of foundation in the Middle
411
00:23:48.319 --> 00:23:51.910 A:middle L:90%
East, which is basically an augured pile. It's
412
00:23:51.910 --> 00:23:53.269 A:middle L:90%
a friction pile, there's very little end bearing,
413
00:23:53.740 --> 00:24:00.380 A:middle L:90%
it's usually constructed under bentonite or polymer slurry, but
414
00:24:00.380 --> 00:24:02.400 A:middle L:90%
it's done over and over and over again in the
415
00:24:02.400 --> 00:24:06.559 A:middle L:90%
Middle East on top of the piles is up uh
416
00:24:06.569 --> 00:24:08.769 A:middle L:90%
five metre thick raft foundation, tying them all together
417
00:24:10.140 --> 00:24:12.769 A:middle L:90%
. So that rap is also completed. Now,
418
00:24:14.700 --> 00:24:15.480 A:middle L:90%
the one thing you'll probably say is I get it
419
00:24:15.490 --> 00:24:18.380 A:middle L:90%
, you know, that the towers tolerant in the
420
00:24:18.380 --> 00:24:21.349 A:middle L:90%
center of the building, so therefore the in the
421
00:24:21.349 --> 00:24:26.950 A:middle L:90%
center of the building uh wrong. Uh Here's what
422
00:24:26.950 --> 00:24:30.380 A:middle L:90%
happened. There's um there's a good deal of soil
423
00:24:30.380 --> 00:24:33.559 A:middle L:90%
structure interaction going between the tower and the foundations.
424
00:24:34.039 --> 00:24:37.910 A:middle L:90%
And the best way to think of it is is
425
00:24:37.910 --> 00:24:41.609 A:middle L:90%
if if the foundation itself without the stiffening effect of
426
00:24:41.609 --> 00:24:44.599 A:middle L:90%
the walls of the tower, if it's not stiff
427
00:24:44.599 --> 00:24:48.859 A:middle L:90%
enough because it's a continuous bearing wall. Though bearing
428
00:24:48.859 --> 00:24:52.789 A:middle L:90%
walls themselves will try to limit the differential settlement so
429
00:24:52.789 --> 00:24:56.359 A:middle L:90%
they'll actually be stressed. The superstructure will be stressed
430
00:24:56.359 --> 00:24:57.920 A:middle L:90%
, not the piles And what we found if you
431
00:24:57.920 --> 00:25:00.200 A:middle L:90%
look on the left, if we use all short
432
00:25:00.200 --> 00:25:03.950 A:middle L:90%
piles, 45 m piles were getting. This is
433
00:25:03.950 --> 00:25:04.809 A:middle L:90%
just with the loads. This isn't with the tower
434
00:25:04.809 --> 00:25:07.900 A:middle L:90%
on top of the model. This is just with
435
00:25:07.900 --> 00:25:11.589 A:middle L:90%
the loads from the tower, 170 of settlement with
436
00:25:11.589 --> 00:25:15.319 A:middle L:90%
a differential between the middle and the outside of 85
437
00:25:15.319 --> 00:25:19.339 A:middle L:90%
mm. With the same loads from the tower again
438
00:25:19.339 --> 00:25:23.259 A:middle L:90%
, just putting the loads on a foundation settlement analysis
439
00:25:23.940 --> 00:25:29.349 A:middle L:90%
, if we do the longer piles in the center
440
00:25:29.740 --> 00:25:32.079 A:middle L:90%
And the shorter piles on the wing, the total
441
00:25:32.079 --> 00:25:34.769 A:middle L:90%
is reduced 115 mm in. The differential is 25
442
00:25:34.769 --> 00:25:37.140 A:middle L:90%
mm. So what you're seeing there is you're seeing
443
00:25:37.140 --> 00:25:41.190 A:middle L:90%
a system, a foundation system with the longer piles
444
00:25:41.259 --> 00:25:42.720 A:middle L:90%
that's set up for the tower to be resting on
445
00:25:42.720 --> 00:25:45.509 A:middle L:90%
it properly. And that's that, that took a
446
00:25:45.509 --> 00:25:48.269 A:middle L:90%
fair amount of work to get to that point.
447
00:25:48.740 --> 00:25:51.839 A:middle L:90%
And the thing that we did is we looked at
448
00:25:51.839 --> 00:25:53.779 A:middle L:90%
the base of the tower in these two situations.
449
00:25:53.789 --> 00:25:56.359 A:middle L:90%
The situation on the left, what happens is you
450
00:25:56.359 --> 00:26:00.539 A:middle L:90%
get very high stresses in the bottom few stories of
451
00:26:00.539 --> 00:26:03.210 A:middle L:90%
the tower, if you have only short piles,
452
00:26:03.220 --> 00:26:06.420 A:middle L:90%
because the tower itself is trying to there can't really
453
00:26:06.420 --> 00:26:08.859 A:middle L:90%
be differential settlement when you have walls are kilometer tall
454
00:26:10.140 --> 00:26:12.470 A:middle L:90%
, it's impossible. So what what happens is the
455
00:26:12.470 --> 00:26:17.500 A:middle L:90%
tower tries to restrain that differential settlement itself and actually
456
00:26:17.500 --> 00:26:19.079 A:middle L:90%
get stressed on the right side is where we have
457
00:26:19.079 --> 00:26:22.559 A:middle L:90%
the piles that we ended up with. Those stresses
458
00:26:22.559 --> 00:26:26.009 A:middle L:90%
were reduced dramatically In that case. So I'll let
459
00:26:26.009 --> 00:26:26.930 A:middle L:90%
you ponder that a little bit. It's not not
460
00:26:26.930 --> 00:26:30.410 A:middle L:90%
obvious, but it's one of the interesting things in
461
00:26:30.420 --> 00:26:33.359 A:middle L:90%
designing these tall towers, you get into things that
462
00:26:33.359 --> 00:26:34.440 A:middle L:90%
for a 40 or 50 story building, it would
463
00:26:34.440 --> 00:26:37.680 A:middle L:90%
be almost irrelevant. You'll never get into something like
464
00:26:37.680 --> 00:26:42.339 A:middle L:90%
this we're expecting uh at the end of construction,
465
00:26:42.349 --> 00:26:45.690 A:middle L:90%
about what about four inches of settlement for the tower
466
00:26:45.809 --> 00:26:48.880 A:middle L:90%
. The interesting thing is the tower has several buildings
467
00:26:48.880 --> 00:26:51.700 A:middle L:90%
around it. I showed you the master plan,
468
00:26:51.700 --> 00:26:55.289 A:middle L:90%
but there's podiums that house all the parking and and
469
00:26:55.289 --> 00:26:56.299 A:middle L:90%
some of the amenities for the hotel like that,
470
00:26:56.309 --> 00:27:00.049 A:middle L:90%
there's a, a conference center and so forth.
471
00:27:00.099 --> 00:27:02.680 A:middle L:90%
What happens is we told them they could they shouldn't
472
00:27:02.680 --> 00:27:03.880 A:middle L:90%
build the buildings around the tower, because what will
473
00:27:03.880 --> 00:27:06.940 A:middle L:90%
happen is the tower as it gets built, it
474
00:27:06.940 --> 00:27:11.569 A:middle L:90%
will draw down the buildings around it. There's a
475
00:27:11.579 --> 00:27:15.349 A:middle L:90%
zone of influence for the tower as it gets built
476
00:27:15.410 --> 00:27:18.259 A:middle L:90%
, it will the dish everything around it. Obviously
477
00:27:18.259 --> 00:27:19.740 A:middle L:90%
the further you get away from the tower the less
478
00:27:19.740 --> 00:27:22.819 A:middle L:90%
that influences. But the longer you can wait the
479
00:27:22.819 --> 00:27:26.210 A:middle L:90%
less problems you'll have with this sort of dishing and
480
00:27:26.210 --> 00:27:29.369 A:middle L:90%
the influence of the tower drawing down the buildings around
481
00:27:29.369 --> 00:27:33.900 A:middle L:90%
it. In terms of seismicity, I would characterize
482
00:27:33.900 --> 00:27:37.279 A:middle L:90%
it as moderate to low if there's a fault in
483
00:27:37.279 --> 00:27:42.359 A:middle L:90%
the middle of the Red Sea. Um But the
484
00:27:42.839 --> 00:27:48.390 A:middle L:90%
the Arabian peninsula is basically stable. There's very very
485
00:27:48.390 --> 00:27:52.650 A:middle L:90%
little activity within the peninsula itself. It's you can
486
00:27:52.650 --> 00:27:56.450 A:middle L:90%
see obviously in Iran there's a lot of activity but
487
00:27:56.460 --> 00:28:00.220 A:middle L:90%
they're basically the Arabian plate is moving slowly but surely
488
00:28:00.220 --> 00:28:02.890 A:middle L:90%
towards Iran. Are kept telling that to our client
489
00:28:02.900 --> 00:28:06.289 A:middle L:90%
Saudi client. I said you know the Arabian peninsula
490
00:28:06.289 --> 00:28:08.440 A:middle L:90%
is moving toward Iran and he'd always smile and say
491
00:28:08.450 --> 00:28:11.269 A:middle L:90%
very funny mr since if you know if you know
492
00:28:11.640 --> 00:28:15.809 A:middle L:90%
mhm mm. But you can see some of the
493
00:28:15.809 --> 00:28:18.619 A:middle L:90%
activity obviously in Iran, there's a lot of activity
494
00:28:18.630 --> 00:28:22.269 A:middle L:90%
, there's a little there's uh influence at the Sinai
495
00:28:22.269 --> 00:28:23.779 A:middle L:90%
, there was some activity for far field effects and
496
00:28:23.779 --> 00:28:27.339 A:middle L:90%
so forth. But by and large the tower is
497
00:28:27.339 --> 00:28:30.420 A:middle L:90%
controlled by wind. I think you probably guess that
498
00:28:30.430 --> 00:28:32.160 A:middle L:90%
already. And what we do at the beginning of
499
00:28:32.160 --> 00:28:34.150 A:middle L:90%
the project is we always try to mark where are
500
00:28:34.150 --> 00:28:37.539 A:middle L:90%
we at in terms of the basic wind speed,
501
00:28:37.539 --> 00:28:40.079 A:middle L:90%
that's the best way of figuring out what kind of
502
00:28:40.079 --> 00:28:41.710 A:middle L:90%
effect you're going to have for wind. So we
503
00:28:41.710 --> 00:28:44.759 A:middle L:90%
look at what we're used to were used to Chicago
504
00:28:44.759 --> 00:28:45.240 A:middle L:90%
, were used to new york were now we're even
505
00:28:45.240 --> 00:28:48.990 A:middle L:90%
used to Dubai, here's Jeddah. The code wind
506
00:28:48.990 --> 00:28:52.069 A:middle L:90%
is 42.2 m/s, that's a three second gust.
507
00:28:52.079 --> 00:28:56.710 A:middle L:90%
Basic wind speed. The climate, the actual climate
508
00:28:56.720 --> 00:28:59.099 A:middle L:90%
that's brought from the wind tunnel is quite a bit
509
00:28:59.099 --> 00:29:00.789 A:middle L:90%
lower, but this is what we have to design
510
00:29:00.799 --> 00:29:04.460 A:middle L:90%
for for strength. But compared to places like Miami
511
00:29:04.460 --> 00:29:07.519 A:middle L:90%
and Hong kong where you get into hurricanes were nothing
512
00:29:07.519 --> 00:29:11.240 A:middle L:90%
like that. So it's a fairly moderate wind climate
513
00:29:11.240 --> 00:29:15.690 A:middle L:90%
. So between foundation conditions, those are critical.
514
00:29:15.690 --> 00:29:18.670 A:middle L:90%
If you're going to do a tall building low to
515
00:29:18.670 --> 00:29:22.450 A:middle L:90%
moderate seismicity, reasonable wind speeds, all in all
516
00:29:22.940 --> 00:29:25.849 A:middle L:90%
high strength concrete availability. Not a bad place for
517
00:29:25.849 --> 00:29:29.119 A:middle L:90%
a tall building actually. You know, sometimes one
518
00:29:29.119 --> 00:29:33.130 A:middle L:90%
of those four things is one you can't overcome actually
519
00:29:33.140 --> 00:29:40.400 A:middle L:90%
to build something quite this tall In terms of the
520
00:29:40.410 --> 00:29:42.640 A:middle L:90%
dynamics of the building, the first period, first
521
00:29:42.640 --> 00:29:45.890 A:middle L:90%
fundamental period is about 12 seconds. We think for
522
00:29:45.890 --> 00:29:49.369 A:middle L:90%
such a tall building and such a massive building that's
523
00:29:49.369 --> 00:29:52.529 A:middle L:90%
really quite stiff. When you think about the old
524
00:29:52.529 --> 00:29:56.210 A:middle L:90%
world trade centers, the twin towers had fundamental periods
525
00:29:56.210 --> 00:29:57.559 A:middle L:90%
approaching 10 seconds. So this is much taller.
526
00:29:59.039 --> 00:30:00.819 A:middle L:90%
The third mode is tours in a 5.8 seconds and
527
00:30:00.819 --> 00:30:04.680 A:middle L:90%
we think that's actually reasonable and quite low period for
528
00:30:04.680 --> 00:30:07.920 A:middle L:90%
a building of this height as well. Very pure
529
00:30:07.920 --> 00:30:11.589 A:middle L:90%
modes. You can see there now as you can
530
00:30:11.589 --> 00:30:15.059 A:middle L:90%
imagine, there's been all kinds of wind tunnel testing
531
00:30:15.059 --> 00:30:17.240 A:middle L:90%
. I think we've done no fewer than eight tests
532
00:30:17.640 --> 00:30:18.880 A:middle L:90%
. We started as soon as we won the competition
533
00:30:18.880 --> 00:30:22.180 A:middle L:90%
, we started with the most basic test of all
534
00:30:22.190 --> 00:30:25.619 A:middle L:90%
, which is a very 1 to 8 hundreds of
535
00:30:25.619 --> 00:30:29.069 A:middle L:90%
small model, fixed based model. All everything is
536
00:30:29.069 --> 00:30:30.759 A:middle L:90%
measured at the base. The so called high frequency
537
00:30:30.769 --> 00:30:34.059 A:middle L:90%
force balance test. We just wanted to get some
538
00:30:34.059 --> 00:30:37.000 A:middle L:90%
results so that we start to get an idea of
539
00:30:37.000 --> 00:30:38.099 A:middle L:90%
how we're doing in terms of design forces and the
540
00:30:38.099 --> 00:30:44.660 A:middle L:90%
performance. We moved into pressure integration models. These
541
00:30:44.660 --> 00:30:47.910 A:middle L:90%
models have pressure taps over the entire surface. So
542
00:30:47.910 --> 00:30:49.869 A:middle L:90%
they're measuring even though the bases rigid, they're actually
543
00:30:49.869 --> 00:30:52.259 A:middle L:90%
measuring not at the base but all over the surface
544
00:30:52.259 --> 00:30:56.200 A:middle L:90%
. So they take all these instantaneous pressures are able
545
00:30:56.200 --> 00:30:59.150 A:middle L:90%
to integrate those to give us the design forces and
546
00:30:59.150 --> 00:31:02.170 A:middle L:90%
responses. So that's the so called high frequency pressure
547
00:31:02.170 --> 00:31:07.450 A:middle L:90%
integration model we went into because The spire was so
548
00:31:07.450 --> 00:31:10.509 A:middle L:90%
slender, they couldn't get enough taps in the tower
549
00:31:10.519 --> 00:31:12.049 A:middle L:90%
in the top of the spire. So we actually
550
00:31:12.049 --> 00:31:15.569 A:middle L:90%
did a model at 1-400 scale, just the top
551
00:31:15.569 --> 00:31:18.329 A:middle L:90%
half of the building. And so they were able
552
00:31:18.329 --> 00:31:19.079 A:middle L:90%
to at a larger scale and they were able to
553
00:31:19.079 --> 00:31:22.359 A:middle L:90%
get enough taps in there and then analytically they can
554
00:31:22.359 --> 00:31:25.619 A:middle L:90%
stitch that together with the results from the larger scale
555
00:31:25.619 --> 00:31:29.289 A:middle L:90%
model. So that was a refinement. And then
556
00:31:29.289 --> 00:31:32.059 A:middle L:90%
finally, the most sophisticated models that were able to
557
00:31:32.059 --> 00:31:34.369 A:middle L:90%
do uh these days are the air elastic models and
558
00:31:34.369 --> 00:31:37.900 A:middle L:90%
the air elastic models are again measured at the base
559
00:31:37.900 --> 00:31:40.630 A:middle L:90%
. But it's the only type of model that isn't
560
00:31:40.630 --> 00:31:42.420 A:middle L:90%
rigid. All other models are rigid. This one
561
00:31:42.420 --> 00:31:45.170 A:middle L:90%
actually has the feedback effects of the tower moving in
562
00:31:45.170 --> 00:31:48.559 A:middle L:90%
the wind in the wind tunnel and you don't want
563
00:31:48.559 --> 00:31:49.400 A:middle L:90%
to do those. Those are very expensive models.
564
00:31:49.400 --> 00:31:52.779 A:middle L:90%
You want to wait on those until everything is settled
565
00:31:52.779 --> 00:31:56.910 A:middle L:90%
with the architects and even the structural engineering. On
566
00:31:56.910 --> 00:31:59.680 A:middle L:90%
top of that, I'll get into the upper level
567
00:31:59.680 --> 00:32:02.079 A:middle L:90%
wind climate event. But we also did an independent
568
00:32:02.079 --> 00:32:06.500 A:middle L:90%
wind tunnel tests in a second wind tunnel. Most
569
00:32:06.509 --> 00:32:07.500 A:middle L:90%
most of the testing was done at R. W
570
00:32:07.500 --> 00:32:12.549 A:middle L:90%
. D. Laboratories at Wealth in Ontario Canada.
571
00:32:13.140 --> 00:32:15.950 A:middle L:90%
We did a separate companion model in the University of
572
00:32:15.950 --> 00:32:20.789 A:middle L:90%
Western Ontario at the boundary layer wind tunnel laboratory there
573
00:32:21.240 --> 00:32:23.329 A:middle L:90%
we gave them the same geometry as we gave our
574
00:32:23.329 --> 00:32:25.150 A:middle L:90%
W. D. I. We gave them the
575
00:32:25.150 --> 00:32:29.470 A:middle L:90%
same structural properties and we told the boundary layer,
576
00:32:29.470 --> 00:32:30.829 A:middle L:90%
don't talk to our W. D. I.
577
00:32:30.839 --> 00:32:32.440 A:middle L:90%
Just give us your results and we compared the two
578
00:32:32.440 --> 00:32:35.849 A:middle L:90%
and after I would say a little bit of discussion
579
00:32:36.440 --> 00:32:38.089 A:middle L:90%
, uh quite a bit of discussion actually, the
580
00:32:38.089 --> 00:32:42.190 A:middle L:90%
results were pretty close and people say well how can
581
00:32:42.190 --> 00:32:44.069 A:middle L:90%
it be different? Wind tunnel testing is wind tunnel
582
00:32:44.069 --> 00:32:45.930 A:middle L:90%
testing? The models are very similar. There's no
583
00:32:45.930 --> 00:32:49.130 A:middle L:90%
difference in the models, There's really, in my
584
00:32:49.130 --> 00:32:52.259 A:middle L:90%
opinion, very little difference in the wind tunnels themselves
585
00:32:52.269 --> 00:32:54.319 A:middle L:90%
. What is different is how they treat the climate
586
00:32:54.329 --> 00:32:58.920 A:middle L:90%
, The basic climate model that they use to get
587
00:32:58.920 --> 00:33:06.299 A:middle L:90%
the results from the testing itself. Now, one
588
00:33:06.299 --> 00:33:07.960 A:middle L:90%
thing that came up in the in the wind engineering
589
00:33:08.440 --> 00:33:14.470 A:middle L:90%
is that The wind speeds above 600 m, you're
590
00:33:14.470 --> 00:33:16.009 A:middle L:90%
basically getting away from the atmospheric boundary layer, which
591
00:33:16.009 --> 00:33:19.289 A:middle L:90%
is the influence of the earth on the wind speeds
592
00:33:19.329 --> 00:33:21.759 A:middle L:90%
. So there was some uncertainty about the wind speeds
593
00:33:21.759 --> 00:33:23.930 A:middle L:90%
above that height. And this came up on the
594
00:33:23.930 --> 00:33:27.279 A:middle L:90%
Burj khalifa as well. It obviously doesn't come up
595
00:33:27.279 --> 00:33:30.519 A:middle L:90%
very often, but there was some idea of what
596
00:33:30.519 --> 00:33:32.470 A:middle L:90%
happens to the normal power law is basically the wind
597
00:33:32.470 --> 00:33:37.720 A:middle L:90%
speeds just continue to go up basically. Just goes
598
00:33:37.720 --> 00:33:40.190 A:middle L:90%
up as symptomatically or, you know, power law
599
00:33:40.190 --> 00:33:44.410 A:middle L:90%
, basically. Um, But the question is what
600
00:33:44.420 --> 00:33:46.220 A:middle L:90%
really does happen above 600 m. So they did
601
00:33:46.220 --> 00:33:52.599 A:middle L:90%
use several techniques that are new, balloon launches were
602
00:33:52.599 --> 00:33:55.359 A:middle L:90%
used from the airport that the most airports actually do
603
00:33:55.359 --> 00:33:58.809 A:middle L:90%
have balloon launches. They can get some data from
604
00:33:58.809 --> 00:34:01.269 A:middle L:90%
very high altitudes on wind speeds, but they did
605
00:34:01.269 --> 00:34:05.799 A:middle L:90%
something very different. They actually looked at the much
606
00:34:05.799 --> 00:34:07.760 A:middle L:90%
more detailed analysis of the wind speeds that were measured
607
00:34:07.760 --> 00:34:10.349 A:middle L:90%
at the airport. I'm talking about surface wind speeds
608
00:34:10.739 --> 00:34:14.210 A:middle L:90%
. They actually modeled the airport to see the shielding
609
00:34:14.219 --> 00:34:16.519 A:middle L:90%
of those and tried to correct for that. But
610
00:34:16.519 --> 00:34:19.039 A:middle L:90%
the one thing they did that was probably the most
611
00:34:19.039 --> 00:34:22.900 A:middle L:90%
important is they did something called a weather resource forecasting
612
00:34:22.900 --> 00:34:25.219 A:middle L:90%
model. So basically all of the, the weather
613
00:34:25.230 --> 00:34:29.309 A:middle L:90%
in the world is in this database that they can
614
00:34:29.309 --> 00:34:31.510 A:middle L:90%
use going backwards. They can actually predict what's going
615
00:34:31.510 --> 00:34:35.510 A:middle L:90%
forward and what they came with all these techniques and
616
00:34:35.510 --> 00:34:37.739 A:middle L:90%
they're all, they all have their merits and demerits
617
00:34:37.739 --> 00:34:42.869 A:middle L:90%
. I suppose this is the weather forecasting model is
618
00:34:42.869 --> 00:34:45.340 A:middle L:90%
we think that the wind speeds that we're using and
619
00:34:45.340 --> 00:34:46.769 A:middle L:90%
the profiles that were using the basic power law that
620
00:34:46.769 --> 00:34:50.380 A:middle L:90%
you see in all the textbooks on wind speeds with
621
00:34:50.380 --> 00:34:53.800 A:middle L:90%
height, probably our our conservative we certainly didn't design
622
00:34:53.800 --> 00:34:57.420 A:middle L:90%
to uh, you know, a profile that looks
623
00:34:57.420 --> 00:34:59.949 A:middle L:90%
almost vertical here where there's almost no increase of wind
624
00:34:59.949 --> 00:35:01.280 A:middle L:90%
speed. We used we used the normal but this
625
00:35:01.280 --> 00:35:06.199 A:middle L:90%
whole effort of verifying the wind speeds at high elevations
626
00:35:06.199 --> 00:35:07.519 A:middle L:90%
was to make sure that we were being conservative with
627
00:35:07.519 --> 00:35:10.099 A:middle L:90%
what we're doing with our engineering. That was a
628
00:35:10.099 --> 00:35:14.969 A:middle L:90%
very important part of the project. We determined from
629
00:35:14.969 --> 00:35:16.219 A:middle L:90%
the uh, we call it the upper level wind
630
00:35:16.219 --> 00:35:19.539 A:middle L:90%
climate assessment. It's a long term of saying the
631
00:35:19.539 --> 00:35:22.619 A:middle L:90%
wind speeds at height That the 42.2 m/s, which
632
00:35:22.619 --> 00:35:27.329 A:middle L:90%
is specified in the Saudi building code at 50 years
633
00:35:27.329 --> 00:35:30.050 A:middle L:90%
three second gust really from the climate data is equivalent
634
00:35:30.050 --> 00:35:34.429 A:middle L:90%
to about 870 year return period. So we think
635
00:35:34.429 --> 00:35:37.940 A:middle L:90%
it's very conservative and the Saudis are very conservative.
636
00:35:37.940 --> 00:35:38.719 A:middle L:90%
So they made us designed for it anyway. And
637
00:35:38.719 --> 00:35:42.869 A:middle L:90%
we did. But uh, you know, that's
638
00:35:42.869 --> 00:35:45.170 A:middle L:90%
something that makes you at least have something in your
639
00:35:45.170 --> 00:35:46.849 A:middle L:90%
backpack and feel a little bit better about your design
640
00:35:49.320 --> 00:35:51.309 A:middle L:90%
. In terms of software that we use, we
641
00:35:51.309 --> 00:35:54.760 A:middle L:90%
use practically every program you've probably heard of. We
642
00:35:54.760 --> 00:35:59.000 A:middle L:90%
do use obviously e tabs and SAP quite a bit
643
00:35:59.000 --> 00:36:00.349 A:middle L:90%
. That's the sort of the bare, bare bones
644
00:36:00.349 --> 00:36:04.300 A:middle L:90%
of what we do. We use a program called
645
00:36:04.300 --> 00:36:07.230 A:middle L:90%
Midas gen. I'll give you some details on that
646
00:36:07.239 --> 00:36:08.900 A:middle L:90%
. We use Strand and we use advocates for some
647
00:36:08.900 --> 00:36:10.699 A:middle L:90%
of the buckling studies that we did, sort of
648
00:36:10.699 --> 00:36:15.780 A:middle L:90%
global global studies on the tower itself. The other
649
00:36:15.780 --> 00:36:17.519 A:middle L:90%
thing that we do that I like to do is
650
00:36:17.590 --> 00:36:21.780 A:middle L:90%
as we move from the various design phases of the
651
00:36:21.780 --> 00:36:24.429 A:middle L:90%
project, from schematic design, for example, early
652
00:36:24.429 --> 00:36:29.949 A:middle L:90%
on to design development into final design. We tend
653
00:36:29.949 --> 00:36:34.519 A:middle L:90%
to uh take a start a new model. So
654
00:36:34.519 --> 00:36:36.420 A:middle L:90%
we will not only start a new model, we
655
00:36:36.420 --> 00:36:37.420 A:middle L:90%
will start in a new program in in a new
656
00:36:37.420 --> 00:36:43.190 A:middle L:90%
engineer. This is a quality control maneuver because um
657
00:36:43.199 --> 00:36:45.300 A:middle L:90%
if you don't, if you just have one model
658
00:36:45.300 --> 00:36:45.789 A:middle L:90%
, what are you checking against? You're not checking
659
00:36:45.789 --> 00:36:50.010 A:middle L:90%
against anything. So by having several models being done
660
00:36:50.010 --> 00:36:52.269 A:middle L:90%
by different engineers, you can check the results to
661
00:36:52.269 --> 00:36:55.190 A:middle L:90%
see if there's consistency, uh and different programs as
662
00:36:55.190 --> 00:36:57.780 A:middle L:90%
well. So we do do that quite a bit
663
00:36:57.780 --> 00:37:00.079 A:middle L:90%
for these major projects. I think it's very important
664
00:37:00.099 --> 00:37:00.769 A:middle L:90%
. We had a we had a model during the
665
00:37:00.769 --> 00:37:04.880 A:middle L:90%
competition and as soon as we started the actual schematic
666
00:37:04.880 --> 00:37:07.510 A:middle L:90%
design, we started a whole new model from scratch
667
00:37:07.510 --> 00:37:10.110 A:middle L:90%
even though nothing really changed from the competition. And
668
00:37:10.110 --> 00:37:13.650 A:middle L:90%
yes, it's time consuming. But honestly, these
669
00:37:13.650 --> 00:37:15.030 A:middle L:90%
models don't take that long to build. I would
670
00:37:15.030 --> 00:37:19.800 A:middle L:90%
say that building this model in Need tabs is a
671
00:37:19.800 --> 00:37:22.869 A:middle L:90%
matter of maybe 2, 34 weeks, it's not
672
00:37:22.869 --> 00:37:27.739 A:middle L:90%
234 months and most of the effort is getting the
673
00:37:28.130 --> 00:37:30.170 A:middle L:90%
uh, gravity loads in. The geometry is very
674
00:37:30.170 --> 00:37:34.329 A:middle L:90%
simple. We usually take autocad or another three dimensional
675
00:37:34.329 --> 00:37:37.920 A:middle L:90%
program and import it into the program first. So
676
00:37:37.929 --> 00:37:39.659 A:middle L:90%
they don't take that long to build these days.
677
00:37:42.630 --> 00:37:45.070 A:middle L:90%
This is a share and overturning moment cumulative plot,
678
00:37:45.079 --> 00:37:49.960 A:middle L:90%
basically saying that the wind loads govern over seismic.
679
00:37:49.969 --> 00:37:52.090 A:middle L:90%
That's what you should basically glean from this by by
680
00:37:52.090 --> 00:37:54.590 A:middle L:90%
a wide margin. Obviously, I would say that
681
00:37:54.599 --> 00:37:58.789 A:middle L:90%
the tipping point is much lower. Buildings in this
682
00:37:58.789 --> 00:38:00.800 A:middle L:90%
, in this kind of seismic zone, probably 400
683
00:38:00.800 --> 00:38:04.510 A:middle L:90%
m and below. Might be controlled by seismic.
684
00:38:04.519 --> 00:38:07.130 A:middle L:90%
But anything of this height, there's no question will
685
00:38:07.130 --> 00:38:09.969 A:middle L:90%
be governed by wind. This is a drift pot
686
00:38:09.969 --> 00:38:12.909 A:middle L:90%
. You can see it's non linear. The spire
687
00:38:12.909 --> 00:38:15.469 A:middle L:90%
at the top does get quite non linear, but
688
00:38:15.480 --> 00:38:19.400 A:middle L:90%
you know, but the building is quite stiff in
689
00:38:19.400 --> 00:38:21.329 A:middle L:90%
terms of the motions, I'll get to that here
690
00:38:22.920 --> 00:38:23.449 A:middle L:90%
. So this is what we do for the for
691
00:38:23.449 --> 00:38:27.489 A:middle L:90%
the motions. This is the perception of the motion
692
00:38:27.489 --> 00:38:29.440 A:middle L:90%
of the building by the occupants. And what we
693
00:38:29.440 --> 00:38:32.440 A:middle L:90%
use is the I. S. O 10137 is
694
00:38:32.440 --> 00:38:38.230 A:middle L:90%
the standard criteria we use nowadays. And this this
695
00:38:38.230 --> 00:38:40.340 A:middle L:90%
we usually use a one year criteria. So you're
696
00:38:40.340 --> 00:38:43.349 A:middle L:90%
looking at a storm that on average is going to
697
00:38:43.349 --> 00:38:46.309 A:middle L:90%
be on a yearly event. And the so would
698
00:38:46.309 --> 00:38:50.099 A:middle L:90%
tell you that for the top occupied floor, which
699
00:38:50.099 --> 00:38:53.769 A:middle L:90%
is at 654 m in the air, well over
700
00:38:53.780 --> 00:38:59.340 A:middle L:90%
2000 ft. Um The criteria would be about 12
701
00:38:59.340 --> 00:39:01.989 A:middle L:90%
million, Jeez is what is acceptable for the motion
702
00:39:01.989 --> 00:39:05.829 A:middle L:90%
on a one year storm based on the fundamental period
703
00:39:05.829 --> 00:39:08.900 A:middle L:90%
of our building and the esso criteria and the predictions
704
00:39:08.909 --> 00:39:13.500 A:middle L:90%
from the wind tunnel testing uh Pegged the motion at
705
00:39:13.500 --> 00:39:15.889 A:middle L:90%
about five or six million, jeez so this is
706
00:39:15.889 --> 00:39:16.820 A:middle L:90%
going to be, in my opinion, a very
707
00:39:16.820 --> 00:39:20.920 A:middle L:90%
comfortable building for the occupants. And why is that
708
00:39:20.929 --> 00:39:22.300 A:middle L:90%
? Why? Why is it so well behaved in
709
00:39:22.300 --> 00:39:25.139 A:middle L:90%
terms of the motion? Most important is that it's
710
00:39:25.139 --> 00:39:29.579 A:middle L:90%
tapered. So the aerodynamics are really quite good.
711
00:39:29.579 --> 00:39:32.559 A:middle L:90%
The vortexes, the vortex shedding phenomenon that you see
712
00:39:32.559 --> 00:39:37.909 A:middle L:90%
, particularly for prismatic buildings that don't change and profile
713
00:39:37.909 --> 00:39:39.489 A:middle L:90%
along the height, this one changes constantly. So
714
00:39:39.489 --> 00:39:43.190 A:middle L:90%
the tapering is very helpful. The other thing that's
715
00:39:43.190 --> 00:39:45.750 A:middle L:90%
extremely helpful is it's very massive, very, very
716
00:39:45.750 --> 00:39:51.809 A:middle L:90%
heavy building and the masses, basically the accelerations uh
717
00:39:51.820 --> 00:39:54.769 A:middle L:90%
go with the inverse of the generalized mass of the
718
00:39:54.769 --> 00:39:58.389 A:middle L:90%
building. So the heavier ever it is, it's
719
00:39:58.389 --> 00:40:00.489 A:middle L:90%
almost a linear distribution. It's also fairly heavy at
720
00:40:00.489 --> 00:40:07.090 A:middle L:90%
the top of the building. Now, I showed
721
00:40:07.090 --> 00:40:09.369 A:middle L:90%
you the deflection plot that gets quite non linear up
722
00:40:09.369 --> 00:40:13.730 A:middle L:90%
in the spire. The building for the occupants itself
723
00:40:13.730 --> 00:40:15.000 A:middle L:90%
requires no damper whatsoever. It's going to be very
724
00:40:15.000 --> 00:40:17.809 A:middle L:90%
very comfortable. But the motions in the spire starting
725
00:40:17.809 --> 00:40:21.380 A:middle L:90%
to concern me a bit. There will be people
726
00:40:21.380 --> 00:40:22.699 A:middle L:90%
in the spire, there will be maintenance workers.
727
00:40:22.710 --> 00:40:25.530 A:middle L:90%
Uh They have to go up and change light bulbs
728
00:40:25.530 --> 00:40:27.900 A:middle L:90%
every once in a while. So there'll be a
729
00:40:27.900 --> 00:40:30.210 A:middle L:90%
small lift that goes up into the spire and the
730
00:40:30.210 --> 00:40:32.309 A:middle L:90%
motions up there, we're going to be quite quite
731
00:40:32.320 --> 00:40:37.340 A:middle L:90%
high. So we are putting a damper for the
732
00:40:37.340 --> 00:40:39.429 A:middle L:90%
spire alone. It's being designed right now by our
733
00:40:39.429 --> 00:40:42.489 A:middle L:90%
W. D. I. So that's the plan
734
00:40:42.500 --> 00:40:45.349 A:middle L:90%
to reduce the motions up in the spire by about
735
00:40:45.349 --> 00:40:50.170 A:middle L:90%
30 or 40 by using an auxiliary damping device in
736
00:40:50.170 --> 00:40:53.420 A:middle L:90%
the spire itself. Now there's a lot of coupling
737
00:40:53.420 --> 00:40:58.320 A:middle L:90%
beams in the building and this is something that's sort
738
00:40:58.320 --> 00:41:01.780 A:middle L:90%
of been developing for several years now. Uh there
739
00:41:02.070 --> 00:41:06.690 A:middle L:90%
there's about 6000 of them. Um so we wanted
740
00:41:06.690 --> 00:41:08.639 A:middle L:90%
a consistent way of designing all these coupling beams.
741
00:41:09.010 --> 00:41:12.559 A:middle L:90%
Some of our multi span coupling being, some are
742
00:41:12.570 --> 00:41:16.530 A:middle L:90%
single span, um We're using strut and tie modeling
743
00:41:16.530 --> 00:41:20.019 A:middle L:90%
for all the coupling beams and this has gone gone
744
00:41:20.019 --> 00:41:22.559 A:middle L:90%
around around. It's not that common even today that
745
00:41:22.559 --> 00:41:25.969 A:middle L:90%
engineers are using strut and tie analogy, but for
746
00:41:25.969 --> 00:41:30.280 A:middle L:90%
this one we have 100 and we use uh you
747
00:41:30.280 --> 00:41:34.460 A:middle L:90%
know, uh to be models and one day models
748
00:41:34.469 --> 00:41:36.909 A:middle L:90%
. And we we basically have a menu, so
749
00:41:36.909 --> 00:41:39.070 A:middle L:90%
we basically have a series of designs and then we
750
00:41:39.070 --> 00:41:43.579 A:middle L:90%
fit the coupling beams into those menu of designs.
751
00:41:43.579 --> 00:41:45.510 A:middle L:90%
So we don't take every single coupling beam and have
752
00:41:45.510 --> 00:41:47.829 A:middle L:90%
a separate design for it. We basically group them
753
00:41:49.409 --> 00:41:52.199 A:middle L:90%
to make a little bit easier to build. These
754
00:41:52.199 --> 00:41:54.769 A:middle L:90%
coupling beams get to be very heavily reinforced, as
755
00:41:54.769 --> 00:41:59.010 A:middle L:90%
you might imagine. This is one of the drawbacks
756
00:41:59.010 --> 00:42:00.619 A:middle L:90%
of the bearing wall system. The coupling beams are
757
00:42:00.630 --> 00:42:02.969 A:middle L:90%
tough to build. There's a lot of reinforcement in
758
00:42:02.969 --> 00:42:07.429 A:middle L:90%
them and there's a lot of congestion as well.
759
00:42:07.099 --> 00:42:12.730 A:middle L:90%
And in some places the amount of reinforcement gets to
760
00:42:12.730 --> 00:42:14.030 A:middle L:90%
be so much, you actually have to go to
761
00:42:14.030 --> 00:42:16.840 A:middle L:90%
a steel I shaped beam embedded in the coupling beam
762
00:42:16.840 --> 00:42:20.809 A:middle L:90%
because the shear stresses are higher, much higher than
763
00:42:20.809 --> 00:42:23.269 A:middle L:90%
allowed by code. So there are several places in
764
00:42:23.269 --> 00:42:27.219 A:middle L:90%
the tower where we have to put steel reinforced coupling
765
00:42:27.219 --> 00:42:30.719 A:middle L:90%
beams uh, in the design. So in that
766
00:42:30.719 --> 00:42:32.849 A:middle L:90%
we use some finite element analysis, obviously there's a
767
00:42:32.860 --> 00:42:36.510 A:middle L:90%
, there's a location at the front of the steel
768
00:42:36.510 --> 00:42:37.869 A:middle L:90%
beam that's going to have a very high bearing stresses
769
00:42:37.869 --> 00:42:40.389 A:middle L:90%
. So we look into things like that with separate
770
00:42:40.389 --> 00:42:45.659 A:middle L:90%
sub models for the finite element analysis. Now,
771
00:42:45.659 --> 00:42:47.659 A:middle L:90%
in terms of the construction, what we're anticipating in
772
00:42:47.780 --> 00:42:52.030 A:middle L:90%
and what this contractor has told us is the walls
773
00:42:52.039 --> 00:42:55.210 A:middle L:90%
will go up first. There will be uh probably
774
00:42:55.219 --> 00:42:58.880 A:middle L:90%
5 to 10 stories in front of the slabs,
775
00:42:58.889 --> 00:43:01.469 A:middle L:90%
all of them, not just the central triangular core
776
00:43:01.480 --> 00:43:05.539 A:middle L:90%
. Every single wall will be sticking up Five or
777
00:43:05.539 --> 00:43:08.239 A:middle L:90%
six by maybe 10 at the most floors above any
778
00:43:08.239 --> 00:43:13.489 A:middle L:90%
floor construction. And the floor slabs will be connected
779
00:43:13.489 --> 00:43:15.710 A:middle L:90%
to the, to the walls through these types of
780
00:43:15.710 --> 00:43:17.829 A:middle L:90%
details where you have couplers that are cast in the
781
00:43:17.829 --> 00:43:22.079 A:middle L:90%
wall and then you have basically threaded bars that are
782
00:43:22.079 --> 00:43:24.610 A:middle L:90%
connected and key ways at the face of all the
783
00:43:24.610 --> 00:43:29.230 A:middle L:90%
walls. So the slabs will slowly follow the walls
784
00:43:29.599 --> 00:43:32.019 A:middle L:90%
After 5, 5 to 10 stories to embrace the
785
00:43:32.019 --> 00:43:37.010 A:middle L:90%
walls during the construction. And what we do is
786
00:43:37.010 --> 00:43:39.159 A:middle L:90%
we use a program that the Midas gen program is
787
00:43:39.159 --> 00:43:44.849 A:middle L:90%
a korean program. It's uh it's actually very powerful
788
00:43:44.860 --> 00:43:47.309 A:middle L:90%
in terms of its ability to do stage construction modeling
789
00:43:47.800 --> 00:43:51.760 A:middle L:90%
. Um this is something that's uh been a big
790
00:43:51.760 --> 00:43:54.510 A:middle L:90%
development for tall buildings analytically for structural engineers. 10
791
00:43:54.510 --> 00:43:58.179 A:middle L:90%
or 15 years ago, maybe not even 10 years
792
00:43:58.179 --> 00:44:01.349 A:middle L:90%
ago, we were resorted to spreadsheets. Basically,
793
00:44:01.349 --> 00:44:06.730 A:middle L:90%
you would take up a big core and idealize it
794
00:44:06.730 --> 00:44:07.989 A:middle L:90%
as a big column and you would do a spreadsheet
795
00:44:08.000 --> 00:44:13.610 A:middle L:90%
calculation for the creep and shrinkage calculations of vertical shortening
796
00:44:13.610 --> 00:44:15.369 A:middle L:90%
calculations for that. Then you would take a column
797
00:44:15.369 --> 00:44:16.989 A:middle L:90%
, for example, you do the same thing for
798
00:44:16.989 --> 00:44:20.510 A:middle L:90%
that and you try to link them to, but
799
00:44:20.889 --> 00:44:23.679 A:middle L:90%
that's very difficult to do through spreadsheets. It's idealized
800
00:44:23.840 --> 00:44:28.420 A:middle L:90%
this. You're actually building the building in the computer
801
00:44:28.989 --> 00:44:30.679 A:middle L:90%
in a sequential way and you're building it in the
802
00:44:30.679 --> 00:44:34.800 A:middle L:90%
entire three dimensional domain. It's not a spreadsheet,
803
00:44:35.050 --> 00:44:37.329 A:middle L:90%
it's an analytical model that keeps getting updated. So
804
00:44:37.329 --> 00:44:39.710 A:middle L:90%
what we do is we use the minus programme.
805
00:44:39.929 --> 00:44:43.260 A:middle L:90%
And yes, you know, there's the number of
806
00:44:43.260 --> 00:44:45.739 A:middle L:90%
steps usually are limited. You can do maybe five
807
00:44:45.739 --> 00:44:50.650 A:middle L:90%
story increments, but you build the entire building in
808
00:44:50.650 --> 00:44:52.820 A:middle L:90%
the computer so that when you get done, you
809
00:44:52.820 --> 00:44:58.849 A:middle L:90%
can basically take any member or any location in the
810
00:44:58.849 --> 00:45:02.460 A:middle L:90%
tower and track the forces over time. So you
811
00:45:02.460 --> 00:45:07.019 A:middle L:90%
take the gravity forces at Timex. Are they increasing
812
00:45:07.019 --> 00:45:09.059 A:middle L:90%
or decreasing due to the effects of creep and shrinkage
813
00:45:09.139 --> 00:45:13.079 A:middle L:90%
and elastic shortening of the tower I mentioned before this
814
00:45:13.079 --> 00:45:15.840 A:middle L:90%
tower is very linked. That's a great thing for
815
00:45:15.840 --> 00:45:17.739 A:middle L:90%
the system. But what have what happens is due
816
00:45:17.739 --> 00:45:21.429 A:middle L:90%
to the effects of creep and shrinkage and even elastic
817
00:45:21.429 --> 00:45:24.889 A:middle L:90%
shortening loads get redistributed through those coupling beams long term
818
00:45:24.889 --> 00:45:28.400 A:middle L:90%
and continue to do so over time. And you
819
00:45:28.400 --> 00:45:30.989 A:middle L:90%
can track and predict those those forces. Using the
820
00:45:30.989 --> 00:45:32.940 A:middle L:90%
Midas model, we use it as an engine.
821
00:45:32.949 --> 00:45:37.269 A:middle L:90%
The material curves for the concrete, we develop ourselves
822
00:45:37.280 --> 00:45:40.090 A:middle L:90%
and those are based on the mixed design and some
823
00:45:40.090 --> 00:45:44.579 A:middle L:90%
of the other models we basically use minus only only
824
00:45:44.579 --> 00:45:46.909 A:middle L:90%
to do the the construction. Uh you know,
825
00:45:46.909 --> 00:45:52.539 A:middle L:90%
the stage modeling, this is for example the stresses
826
00:45:52.539 --> 00:45:55.000 A:middle L:90%
in the end walls at overtime, basically they'll build
827
00:45:55.000 --> 00:46:00.309 A:middle L:90%
up until the tower is finished and then they'll slightly
828
00:46:00.309 --> 00:46:01.309 A:middle L:90%
reduce over time. Which is a good thing for
829
00:46:01.309 --> 00:46:04.199 A:middle L:90%
the end walls of course, where does that load
830
00:46:04.199 --> 00:46:06.760 A:middle L:90%
go? It doesn't disappear into the ether, It
831
00:46:06.760 --> 00:46:07.289 A:middle L:90%
has to go somewhere else. So it goes through
832
00:46:07.289 --> 00:46:09.409 A:middle L:90%
the coupling beams to the corridor walls, into the
833
00:46:09.409 --> 00:46:15.460 A:middle L:90%
thin walls. The other thing obviously probably equally if
834
00:46:15.460 --> 00:46:19.550 A:middle L:90%
not more important in terms of the redistribution forces are
835
00:46:19.550 --> 00:46:21.980 A:middle L:90%
the movements of the tower. So we can predict
836
00:46:21.989 --> 00:46:24.489 A:middle L:90%
the vertical movement and then, as you know,
837
00:46:24.880 --> 00:46:30.739 A:middle L:90%
any structure that's asymmetric is going to move horizontally under
838
00:46:30.739 --> 00:46:32.820 A:middle L:90%
its own weight. And Kingdom tower is no different
839
00:46:32.820 --> 00:46:36.260 A:middle L:90%
. Kingdom Tower is asymmetric. I told you that
840
00:46:36.269 --> 00:46:37.840 A:middle L:90%
the three wings reached the top at different locations.
841
00:46:37.840 --> 00:46:40.760 A:middle L:90%
So it is slightly asymmetric. So it will actually
842
00:46:40.760 --> 00:46:45.099 A:middle L:90%
move horizontally under the weight of the tower itself.
843
00:46:45.099 --> 00:46:46.460 A:middle L:90%
So we can actually predict what that will be and
844
00:46:46.460 --> 00:46:50.210 A:middle L:90%
give some instructions to the contractor. So he's aware
845
00:46:50.210 --> 00:46:52.260 A:middle L:90%
of it first of all. So he doesn't freak
846
00:46:52.260 --> 00:46:54.190 A:middle L:90%
out when the building starts moving horizontally on him and
847
00:46:54.190 --> 00:47:00.179 A:middle L:90%
do some compensation for that as well. These are
848
00:47:00.179 --> 00:47:01.840 A:middle L:90%
some of the guidelines we have on our drawing.
849
00:47:01.840 --> 00:47:05.090 A:middle L:90%
This is actually one of our design drawings. So
850
00:47:05.090 --> 00:47:07.000 A:middle L:90%
we give them pictures of the model, some of
851
00:47:07.000 --> 00:47:09.829 A:middle L:90%
the predictions. Um some of the requirements for the
852
00:47:09.829 --> 00:47:14.219 A:middle L:90%
surveying and monitoring of the tower during construction. These
853
00:47:14.219 --> 00:47:15.320 A:middle L:90%
are some of the most important discussions and some of
854
00:47:15.320 --> 00:47:20.849 A:middle L:90%
the most difficult discussions to get right because you can
855
00:47:20.849 --> 00:47:22.519 A:middle L:90%
get something very complicated that the contractor won't be able
856
00:47:22.519 --> 00:47:25.789 A:middle L:90%
to build in a million years needed, sort of
857
00:47:25.789 --> 00:47:29.619 A:middle L:90%
boil it down to something that he can swallow in
858
00:47:29.619 --> 00:47:34.380 A:middle L:90%
terms of his construction. Now, all these creep
859
00:47:34.380 --> 00:47:38.880 A:middle L:90%
and shrinkage calculations are based on testing material testing at
860
00:47:38.880 --> 00:47:43.070 A:middle L:90%
this scale. They're six by 12 cylinders and creep
861
00:47:43.070 --> 00:47:45.070 A:middle L:90%
frames were actually doing testing on the mixed designs for
862
00:47:45.070 --> 00:47:50.159 A:middle L:90%
Kingdom Tower in elaborate Cts laboratory outside Chicago. They
863
00:47:50.159 --> 00:47:52.219 A:middle L:90%
shipped all the constituent materials for the mix, the
864
00:47:52.219 --> 00:47:57.559 A:middle L:90%
aggregates, uh and all of the other cement materials
865
00:47:57.559 --> 00:47:59.989 A:middle L:90%
. They shipped it to Chicago and they're doing the
866
00:47:59.989 --> 00:48:01.670 A:middle L:90%
creep testing. But again this is a picture of
867
00:48:01.679 --> 00:48:06.619 A:middle L:90%
birds actually. But we're taking that data and we're
868
00:48:06.619 --> 00:48:08.989 A:middle L:90%
trying to predict something of a scale, you know
869
00:48:08.989 --> 00:48:12.489 A:middle L:90%
, of these and obviously there is an effect on
870
00:48:12.489 --> 00:48:14.269 A:middle L:90%
that. So we try to do the best we
871
00:48:14.269 --> 00:48:17.179 A:middle L:90%
can. But the research on how these very large
872
00:48:17.179 --> 00:48:21.309 A:middle L:90%
elements behave over time really isn't there yet, There
873
00:48:21.309 --> 00:48:22.489 A:middle L:90%
isn't enough data to do that. So we do
874
00:48:22.489 --> 00:48:28.000 A:middle L:90%
the best we can. All of the drawings these
875
00:48:28.000 --> 00:48:30.050 A:middle L:90%
days. We do in a rabbit program, three
876
00:48:30.050 --> 00:48:36.579 A:middle L:90%
dimensional drawings. So the coordination is actually done in
877
00:48:36.579 --> 00:48:38.550 A:middle L:90%
rabbit And in this case one of the big issues
878
00:48:38.559 --> 00:48:42.739 A:middle L:90%
is penetrations through the walls. All of them have
879
00:48:42.739 --> 00:48:44.590 A:middle L:90%
to be designed. There's no way that you could
880
00:48:44.599 --> 00:48:46.119 A:middle L:90%
build the walls and then try to take a scoring
881
00:48:46.119 --> 00:48:50.719 A:middle L:90%
machine and go through 1.2 m of concrete with a
882
00:48:50.730 --> 00:48:52.420 A:middle L:90%
six diameter hole. So all of them have to
883
00:48:52.420 --> 00:48:55.400 A:middle L:90%
be on the drawings, 15,000 openings through this year
884
00:48:55.400 --> 00:49:00.389 A:middle L:90%
. Walls for for mechanical services, small ones mostly
885
00:49:00.269 --> 00:49:01.940 A:middle L:90%
. So all that's done in the rev IT program
886
00:49:01.940 --> 00:49:06.340 A:middle L:90%
, we can find uh areas that there's a clash
887
00:49:06.340 --> 00:49:09.550 A:middle L:90%
or a problem with the coordination between the structure and
888
00:49:09.559 --> 00:49:13.579 A:middle L:90%
, and the NDP systems. This is some of
889
00:49:13.579 --> 00:49:15.590 A:middle L:90%
the reinforcement of the walls. It gets quite heavy
890
00:49:15.590 --> 00:49:15.960 A:middle L:90%
and the end walls, this is near the bottom
891
00:49:15.960 --> 00:49:19.739 A:middle L:90%
of the tower gets less. After about 20 or
892
00:49:19.739 --> 00:49:22.000 A:middle L:90%
30 stories, it gets quite a bit less.
893
00:49:22.000 --> 00:49:23.429 A:middle L:90%
But you can see the end walls are more heavily
894
00:49:23.429 --> 00:49:28.360 A:middle L:90%
reinforced and more heavily stressed actually. Then, as
895
00:49:28.360 --> 00:49:30.000 A:middle L:90%
you get closer and closer to the central core,
896
00:49:31.769 --> 00:49:35.090 A:middle L:90%
we can do three dimensional rebar drawings and we do
897
00:49:35.090 --> 00:49:37.820 A:middle L:90%
some of those in a program called Tekla, which
898
00:49:37.820 --> 00:49:39.449 A:middle L:90%
is mostly used for steel detailing. But we can
899
00:49:39.449 --> 00:49:43.369 A:middle L:90%
do detailing. This is a picture of the end
900
00:49:43.369 --> 00:49:46.909 A:middle L:90%
walls and that some of the transverse thin walls show
901
00:49:46.909 --> 00:49:50.750 A:middle L:90%
some of the steel coupling beams. So we can
902
00:49:50.750 --> 00:49:52.909 A:middle L:90%
kind of get an idea of the amount of congestion
903
00:49:52.909 --> 00:49:53.429 A:middle L:90%
that might be in some of these walls so that
904
00:49:53.429 --> 00:49:55.690 A:middle L:90%
the contractor knows what he's going to get into when
905
00:49:55.690 --> 00:50:00.150 A:middle L:90%
he builds it okay. A few last things because
906
00:50:00.150 --> 00:50:04.570 A:middle L:90%
I'm running out of time here. But the,
907
00:50:05.360 --> 00:50:07.380 A:middle L:90%
I mentioned, I think I mentioned before that,
908
00:50:07.389 --> 00:50:08.409 A:middle L:90%
you know, tall buildings are one of the few
909
00:50:08.420 --> 00:50:13.489 A:middle L:90%
man made products that really haven't been fully verified at
910
00:50:13.489 --> 00:50:15.230 A:middle L:90%
full scale. You know, we, we do
911
00:50:15.230 --> 00:50:17.460 A:middle L:90%
these final element models, we put a lot of
912
00:50:17.460 --> 00:50:20.989 A:middle L:90%
faith in them. I put faith in him myself
913
00:50:20.989 --> 00:50:23.530 A:middle L:90%
actually. Um, We do wind tunnel testing and
914
00:50:23.530 --> 00:50:28.539 A:middle L:90%
those, those models are at the most 1-500 and
915
00:50:28.550 --> 00:50:31.539 A:middle L:90%
maybe even 1-800. They're pretty small scale models and
916
00:50:31.539 --> 00:50:37.210 A:middle L:90%
they're done in a sort of simulated environment in the
917
00:50:37.210 --> 00:50:42.309 A:middle L:90%
wind tunnel. But there's very, very little Information
918
00:50:42.320 --> 00:50:45.260 A:middle L:90%
of how these buildings are behaving in real scale 1-1
919
00:50:45.260 --> 00:50:47.880 A:middle L:90%
scale compared to when you think about it, automobiles
920
00:50:47.880 --> 00:50:51.050 A:middle L:90%
or airplanes, which you have all kinds of data
921
00:50:51.059 --> 00:50:53.579 A:middle L:90%
on how they behave at full scale. So,
922
00:50:53.590 --> 00:50:57.519 A:middle L:90%
um, there's a huge need, uh, there's
923
00:50:57.519 --> 00:51:00.289 A:middle L:90%
a lot of drawbacks and how that can be accomplished
924
00:51:00.300 --> 00:51:02.969 A:middle L:90%
owners don't really want to know. They don't want
925
00:51:02.969 --> 00:51:06.480 A:middle L:90%
to know bad news, that's for sure. Um
926
00:51:06.489 --> 00:51:08.179 A:middle L:90%
, but what we need to do and it will
927
00:51:08.179 --> 00:51:12.130 A:middle L:90%
happen probably well after I'm finished with my career,
928
00:51:12.130 --> 00:51:15.349 A:middle L:90%
but we need to have a program and I wrote
929
00:51:15.349 --> 00:51:19.030 A:middle L:90%
this program for Kingdom Tower where we have a long
930
00:51:19.030 --> 00:51:22.000 A:middle L:90%
term structural health monitoring program in place. So all
931
00:51:22.000 --> 00:51:23.489 A:middle L:90%
the way from the bottom of the piles to the
932
00:51:23.489 --> 00:51:27.829 A:middle L:90%
top of the spire. We've put a program together
933
00:51:27.829 --> 00:51:32.809 A:middle L:90%
of instrumentation and monitoring program of other buildings behaving all
934
00:51:32.809 --> 00:51:36.440 A:middle L:90%
the way from wind speeds and monitors at the top
935
00:51:36.440 --> 00:51:38.690 A:middle L:90%
of the building, to strain gauges in the walls
936
00:51:39.059 --> 00:51:44.500 A:middle L:90%
, to load cells underneath the raft foundation. And
937
00:51:44.500 --> 00:51:45.730 A:middle L:90%
of course I can't insist upon the client can put
938
00:51:45.730 --> 00:51:47.480 A:middle L:90%
it or not. It's not a code issue.
939
00:51:47.960 --> 00:51:51.300 A:middle L:90%
I can't I can't make them do it. But
940
00:51:51.300 --> 00:51:52.460 A:middle L:90%
so far they've said they're very interested in doing the
941
00:51:52.460 --> 00:51:55.440 A:middle L:90%
program. It's going to be extensive. One of
942
00:51:55.440 --> 00:51:58.989 A:middle L:90%
the question is will the information from it ever make
943
00:51:58.989 --> 00:52:00.900 A:middle L:90%
it into the public domain? I hope it does
944
00:52:00.900 --> 00:52:02.099 A:middle L:90%
so that we can learn a little bit about how
945
00:52:02.099 --> 00:52:06.039 A:middle L:90%
the buildings are behaving. Be wonderful to know if
946
00:52:06.039 --> 00:52:08.650 A:middle L:90%
the periods that we predict from those finite element models
947
00:52:08.650 --> 00:52:12.050 A:middle L:90%
and E. Tabs and SAP are close to what's
948
00:52:12.050 --> 00:52:14.250 A:middle L:90%
measured out there in the site. Most of the
949
00:52:14.250 --> 00:52:17.010 A:middle L:90%
stuff needs the anti monitor data. You can't really
950
00:52:17.019 --> 00:52:21.769 A:middle L:90%
getting data that's just data without any correlation to wind
951
00:52:21.769 --> 00:52:25.829 A:middle L:90%
speed is really almost worthless. But that alone just
952
00:52:25.829 --> 00:52:29.260 A:middle L:90%
to figure out if the building is behaving as predicted
953
00:52:29.260 --> 00:52:31.489 A:middle L:90%
or close to what's predicted would be very interesting.
954
00:52:31.500 --> 00:52:35.449 A:middle L:90%
I've been part of a National Science Foundation program with
955
00:52:35.449 --> 00:52:37.940 A:middle L:90%
the University of Notre Dame instrumented. Uh several buildings
956
00:52:37.940 --> 00:52:42.619 A:middle L:90%
were three buildings actually in Chicago. Tell you it's
957
00:52:42.619 --> 00:52:46.760 A:middle L:90%
very difficult to get meaningful information out of that out
958
00:52:46.760 --> 00:52:49.579 A:middle L:90%
of that because basically when you think about it,
959
00:52:49.579 --> 00:52:51.400 A:middle L:90%
when you put the instruments and you're kind of waiting
960
00:52:51.400 --> 00:52:52.880 A:middle L:90%
for the storm to head, it's kind of like
961
00:52:52.880 --> 00:52:55.000 A:middle L:90%
watching paint dry most days there's not there's not enough
962
00:52:55.000 --> 00:52:58.500 A:middle L:90%
wind for there to be any register in terms of
963
00:52:58.500 --> 00:53:00.400 A:middle L:90%
the data. So it's one of the things that's
964
00:53:00.400 --> 00:53:02.369 A:middle L:90%
one of the things that as we build taller and
965
00:53:02.369 --> 00:53:06.760 A:middle L:90%
taller, we really need to look at and it's
966
00:53:06.760 --> 00:53:07.880 A:middle L:90%
going to be your generation. I think that will
967
00:53:07.880 --> 00:53:10.000 A:middle L:90%
push this kind of thing forward in the future.
968
00:53:10.000 --> 00:53:15.949 A:middle L:90%
I hope here I am at groundbreaking. That steak
969
00:53:15.949 --> 00:53:17.170 A:middle L:90%
, you see there is the geometric center of the
970
00:53:17.170 --> 00:53:20.369 A:middle L:90%
tower. We're out, we're out in the middle
971
00:53:20.369 --> 00:53:23.300 A:middle L:90%
of nowhere. As you can see Uh three gentlemen
972
00:53:23.300 --> 00:53:27.519 A:middle L:90%
to my right there. They're the architects. They
973
00:53:27.530 --> 00:53:30.190 A:middle L:90%
all dressed the same. Yeah, they look like
974
00:53:30.190 --> 00:53:35.349 A:middle L:90%
they work for the CIA, The two gentlemen to
975
00:53:35.349 --> 00:53:39.219 A:middle L:90%
my left or the client. So this is the
976
00:53:39.219 --> 00:53:45.369 A:middle L:90%
piling. This was january Earlier this year. All
977
00:53:45.369 --> 00:53:49.469 A:middle L:90%
the piling was completed. The contractors, Saudi Bauer
978
00:53:50.429 --> 00:53:52.730 A:middle L:90%
, basically a consortium that's a joint venture between a
979
00:53:52.730 --> 00:53:55.880 A:middle L:90%
Saudi piling contractor and a German one did a wonderful
980
00:53:55.880 --> 00:54:00.360 A:middle L:90%
job. Very few problems with the pilot. Even
981
00:54:00.360 --> 00:54:04.170 A:middle L:90%
the 105 m long piles are all in place.
982
00:54:06.139 --> 00:54:09.869 A:middle L:90%
uh in terms of the uh corrosion protection, we
983
00:54:09.869 --> 00:54:15.519 A:middle L:90%
actually have a a system in place with the cathartic
984
00:54:15.519 --> 00:54:19.039 A:middle L:90%
protection for the piling and the raft foundation. So
985
00:54:19.039 --> 00:54:22.570 A:middle L:90%
in addition to having a waterproofing membrane underneath the raft
986
00:54:22.570 --> 00:54:24.619 A:middle L:90%
foundation or the mat foundation, we have cathartic protection
987
00:54:24.619 --> 00:54:27.780 A:middle L:90%
system throughout. You can see the tops of the
988
00:54:27.780 --> 00:54:30.000 A:middle L:90%
piles, they're getting trimmed off and cleaned, getting
989
00:54:30.000 --> 00:54:35.710 A:middle L:90%
ready for the, the matte foundation. And this
990
00:54:35.710 --> 00:54:37.699 A:middle L:90%
is actually fairly, fairly, fairly recent. So
991
00:54:37.960 --> 00:54:40.610 A:middle L:90%
this is the this is five m thick. So
992
00:54:40.610 --> 00:54:45.480 A:middle L:90%
this is the the raft, the tying all the
993
00:54:45.480 --> 00:54:47.889 A:middle L:90%
piles together, five metre thick matte foundation over all
994
00:54:47.889 --> 00:54:52.289 A:middle L:90%
of the 270 piles. It turns out that the
995
00:54:52.289 --> 00:54:53.710 A:middle L:90%
water level is quite close to the surface at our
996
00:54:53.710 --> 00:54:57.679 A:middle L:90%
site. So the rat foundation will actually be in
997
00:54:57.679 --> 00:55:00.550 A:middle L:90%
the bottom story of the, of the garage level
998
00:55:00.559 --> 00:55:01.780 A:middle L:90%
of the tower. You can actually be looking right
999
00:55:01.780 --> 00:55:05.349 A:middle L:90%
at the raft foundation is not buried in the ground
1000
00:55:05.360 --> 00:55:07.570 A:middle L:90%
as most projects are. And then you can begin
1001
00:55:07.570 --> 00:55:09.460 A:middle L:90%
to see some of the walls going up there,
1002
00:55:10.139 --> 00:55:14.320 A:middle L:90%
that's the end wall, lot of reinforcement, corridor
1003
00:55:14.320 --> 00:55:16.750 A:middle L:90%
walls and the thin walls and coupling beams going up
1004
00:55:17.219 --> 00:55:20.400 A:middle L:90%
. And so they've got two or three stories of
1005
00:55:20.400 --> 00:55:23.269 A:middle L:90%
walls going up I believe. Uh the latest is
1006
00:55:23.269 --> 00:55:27.019 A:middle L:90%
that will be finished in 2018, the end of
1007
00:55:27.019 --> 00:55:30.510 A:middle L:90%
2018. It is a real project from if you
1008
00:55:30.510 --> 00:55:31.650 A:middle L:90%
think about it, I think that to one of
1009
00:55:31.650 --> 00:55:34.840 A:middle L:90%
the two most difficult things. Two of the three
1010
00:55:34.849 --> 00:55:38.250 A:middle L:90%
difficult construction challenges on the tower are the pile foundations
1011
00:55:38.260 --> 00:55:40.500 A:middle L:90%
, you can't see them, they're they're drilled into
1012
00:55:40.500 --> 00:55:44.429 A:middle L:90%
the ground, the raft foundation, you can imagine
1013
00:55:44.429 --> 00:55:46.679 A:middle L:90%
the amount of reinforcement and issues with heat of hydration
1014
00:55:46.679 --> 00:55:50.769 A:middle L:90%
and everything else with that. Those are done from
1015
00:55:50.769 --> 00:55:52.340 A:middle L:90%
here on out. It's just walls and slabs and
1016
00:55:52.340 --> 00:55:54.159 A:middle L:90%
I can tell you, Saudi Binladin group knows how
1017
00:55:54.159 --> 00:55:57.679 A:middle L:90%
to do walls and slabs. I wouldn't say it's
1018
00:55:57.679 --> 00:55:59.909 A:middle L:90%
going to be trivial, but I think the third
1019
00:55:59.909 --> 00:56:00.789 A:middle L:90%
thing that's going to be interesting is when they get
1020
00:56:00.789 --> 00:56:04.889 A:middle L:90%
up to around 700 m. that's when the wind
1021
00:56:04.889 --> 00:56:06.880 A:middle L:90%
speeds up there do get quite high and it gets
1022
00:56:06.880 --> 00:56:09.510 A:middle L:90%
difficult, very difficult to build the tower tapers.
1023
00:56:09.510 --> 00:56:12.329 A:middle L:90%
So the cranes are going to have less and less
1024
00:56:12.329 --> 00:56:15.570 A:middle L:90%
structure to be able to Latch onto to stabilize themselves
1025
00:56:15.579 --> 00:56:19.289 A:middle L:90%
. So I'm expecting a call two or three years
1026
00:56:19.289 --> 00:56:21.289 A:middle L:90%
saying, Okay, we're up to 700 m now
1027
00:56:21.289 --> 00:56:24.309 A:middle L:90%
, what do you want me to do? Uh
1028
00:56:24.309 --> 00:56:25.559 A:middle L:90%
, I get this question, I'm going to answer
1029
00:56:25.559 --> 00:56:29.619 A:middle L:90%
the question before it's even asked so how how tall
1030
00:56:29.619 --> 00:56:34.170 A:middle L:90%
can we go? Kingdom Tower? The building in
1031
00:56:34.170 --> 00:56:37.679 A:middle L:90%
the center is frank Lloyd Wright's proposal for Mile high
1032
00:56:37.679 --> 00:56:42.780 A:middle L:90%
skyscraper in Chicago, uh, called the Illinois,
1033
00:56:42.780 --> 00:56:45.380 A:middle L:90%
actually. Um, anyway, there's been a lot
1034
00:56:45.380 --> 00:56:47.110 A:middle L:90%
of conversation in some of the council on tall building
1035
00:56:47.119 --> 00:56:51.780 A:middle L:90%
sessions about it and I was a bit taken back
1036
00:56:51.780 --> 00:56:53.750 A:middle L:90%
. That's mostly engineers, structural engineers saying it's,
1037
00:56:54.329 --> 00:56:58.420 A:middle L:90%
it's uh, there's no problem with the structural engineering
1038
00:56:58.420 --> 00:57:00.769 A:middle L:90%
that anything can be done. There's no limit.
1039
00:57:00.909 --> 00:57:02.289 A:middle L:90%
The limit is going to be because of the elevators
1040
00:57:02.289 --> 00:57:05.309 A:middle L:90%
. It's going to be because of some construction or
1041
00:57:05.309 --> 00:57:07.969 A:middle L:90%
pumping concrete or this or that. I'm not so
1042
00:57:07.969 --> 00:57:10.920 A:middle L:90%
sure. I think that as you get taller and
1043
00:57:10.920 --> 00:57:14.699 A:middle L:90%
taller And if you really want to occupy the buildings
1044
00:57:14.699 --> 00:57:16.139 A:middle L:90%
taller and taller and not just to 600 or 700
1045
00:57:16.139 --> 00:57:21.289 A:middle L:90%
m. the motions up there will get extreme and
1046
00:57:21.289 --> 00:57:24.079 A:middle L:90%
the ability of the contractors to deliver structural materials to
1047
00:57:24.079 --> 00:57:27.239 A:middle L:90%
that height are going to be more and more difficult
1048
00:57:27.730 --> 00:57:29.449 A:middle L:90%
. So I guess I'm a bit of a nay
1049
00:57:29.449 --> 00:57:31.250 A:middle L:90%
Sayer, I'm not saying you couldn't go to 1.1
1050
00:57:31.260 --> 00:57:36.250 A:middle L:90%
kilometer or even 1.4 or 1.5, but a mile
1051
00:57:36.250 --> 00:57:38.239 A:middle L:90%
high skyscraper when you think about it, That's almost
1052
00:57:38.239 --> 00:57:42.159 A:middle L:90%
another 50 or 60 taller than this building. And
1053
00:57:42.159 --> 00:57:44.349 A:middle L:90%
I can tell you if anybody's been to Dubai and
1054
00:57:44.349 --> 00:57:47.050 A:middle L:90%
seeing the Burj Khalifa, that is one unbelievable building
1055
00:57:47.050 --> 00:57:50.239 A:middle L:90%
and this is going to be taller. It really
1056
00:57:50.239 --> 00:57:52.409 A:middle L:90%
is a shocking thing to look at. And if
1057
00:57:52.409 --> 00:57:53.050 A:middle L:90%
you really in your mind's eye say, what does
1058
00:57:53.050 --> 00:57:57.460 A:middle L:90%
a mile high skyscraper look like? I think it
1059
00:57:57.460 --> 00:57:59.400 A:middle L:90%
really, in a way, it's a dream.
1060
00:57:59.409 --> 00:58:00.699 A:middle L:90%
I think it's maybe it'll curb but certainly not in
1061
00:58:00.699 --> 00:58:05.480 A:middle L:90%
my lifetime. No way. And, and I
1062
00:58:05.480 --> 00:58:07.300 A:middle L:90%
think there's a lot of, lot of issues that
1063
00:58:07.300 --> 00:58:08.719 A:middle L:90%
are gonna have to be solved to build to that
1064
00:58:08.719 --> 00:58:13.940 A:middle L:90%
height. So that's my opinion. So hopefully in
1065
00:58:13.940 --> 00:58:17.159 A:middle L:90%
three years, view from Jeddah Harbor will look something
1066
00:58:17.159 --> 00:58:34.030 A:middle L:90%
like that. Thank you. Okay. Yeah.