Well thank you very much for inviting me.
I am very pleased to be here. I have lived in Sydney for 20 years recently
returned to London and am missing the place already so Perth is nearly Sydney it is near
enough for me anyway. I was told I had to talk about the water cube
so I am afraid the first, first half of the talk will be a bit about the water cube but
it is I think the project where we did the most intense collaboration between multiple
disciplines including architecture and various branches of engineering.
And I’ll do my best to try and describe why we took the decisions we took.
It was a competition that we entered in 2003 so the work I am going to describe happened
10 years ago. It is strange for me to think it was that long ago but it was 10 years ago.
And a group of designers came together from PCW Architects from Arup Engineers but also
a firm in China called CCDI who flew their Architects down from Beijing to Sydney to
join the design team for the competition so it was a 10 week competition.
And we did something quite unusual which I am surprised to be able to say to you I’ve
never done before nor since. I can’t work out why I’ve never done it again
but what we did is we lined up the 10 lead engineers leading their disciplines to say
on day one what would success look like to them.
What do they think a swimming centre should be from their discipline perspective?
So the mechanical engineers said look it’s about 14 degrees on average in Beijing during
the year but inside a swimming a centre we would probably want water temperatures of
about 28 especially in a leisure pool to keep people comfortable.
Therefore it is a heating problem and the best way of heating something is simply to
absorb as much solar energy as possible make use of it and stop it getting out. So they
wanted an insulated green house. The lighting electrical engineers said well
from a lighting perspective that would be great too but only if we diffuse the daylight
because actually you get real glare problems if we get direct sunlight reflecting off swimming
pools and it becomes a safety issue. The next people who are highly influential
and often are not even in the room at the beginning of a project were the Acousticians.
They said well that’s all very well chaps but if we make it out of glass it’ll sound
awful. Tiles you need around swimming pools for hygiene
reasons reflects’ sound water reflects sound, if we make the roof and the walls also reflect
sound it will sound appalling and it will be just an unpleasant place to be.
And it was actually the Acousticians that said well look there is this plastic stuff
called ETFE Ethylene Tetrafluoroethylene recently used on the Eden Centre in the UK and it lets
sound through. It doesn’t reflect it except at the very highest
frequency. So if you make your greenhouse out of ETFE
it’ll sound good too. There is by the way a by-product of that it
lets sound in but you know I will let you think about that.
It also sounds a bit like a drum when it rains but we sort of by-passed that bit.
As a structural engineer on the team I said I don’t really care what we do with the structure
too much but I would rather it wasn’t outside because it was likely to be a long span and
it’s likely, therefore to be steel for a cost and strength ratio and in China it is quite
an aggressive polluted atmosphere in Beijing and maintenance is not necessarily their strong
suit while they are busy building more cities than the rest of the world and therefore I
would rather it wasn’t outside. But at the same time inside is also the wrong
place to put steel work in a swimming pool because the chlorine used to disinfect the
pool water is pretty aggressive and turns into sulphuric acid or hydrochloric acid sorry
and attacks, attacks the steel work. I don’t care what we do structurally I just
don’t want it outside nor inside. But of course architects also come in different
flavours. It’s not just the engineering disciplines
that split ourselves up so the, what the Americans call Program Architects and I don’t think
there is quite an equivalent in Australia or in the UK lexicon but those who worry about
how a building should be laid out, which functions goes where, they worked out that really the
key to a successful Olympic swimming centre is very simple.
It’s to have a use after the Olympic. Not so much about the actual competition pool
hall which is very specified. But it’s putting in as much leisure facilities
as possible for the people of Beijing to use it afterwards so they simply maximise the
footprint of the building to fill the whole site which happens to be square and so we
had a square building. The urban designers the people who care about
how the building fits into the environment around them, they said look we’ve got this
brilliant opportunity because the Olympic site (this is a google map of Beijing) is
right on the north south axis of Beijing that goes right through the middle of the forbidden
city and is actually the primary cultural access of Beijing.
Down to the south is the temple of heaven one of the most important cultural sites in
Beijing the east west axis is the commercial axis of Beijing.
We’ve got this opportunity from the master plan that was already proposed that the stadium
and the water, the aquatic centre became the gateway from the city on this major access
into the site for the rest of the Olympics. So what they said is how these two respond
to each other that counts, now these are all very well we put all these things up on day
one and four weeks later we are still arguing about what we are meant to do or what we are
going to do. And the Chinese architects were drawing icebergs
I think if I remember rightly with mist curtains around them.
The Australian architects were drawing wave forms and they both agreed that they wanted
something that was absolutely a sort of a physical manifestation of water if you like.
They thought that was the way to win an international design competition but we didn’t actually
know what to do. And then fortunately our neighbour, the bird’s
nest stadium scheme was published, so they were having a competition at the same time
but a little bit ahead of us. And this winning scheme by Herzog & de Meuron
and also Arup as Engineers came out and was put in the press and we sat there, and I’ll
never forget it, 20 people sat down around a table and we said ok, so theirs’ is red
and round so we will do a blue box ok? And I know it sounds sort of trivial but it
was honestly like that and it was sent me a note “we wanted ying and yang” so red in
Chinese cultural sort of mythology is masculine and blue is feminine, circular things speak
to the heavens, square things speak to the earth.
One is internally focused and one is externally focused.
And at the same we brought all those ideas from the first day which had been sitting
in people’s head but it hadn’t actually been put forward properly yet to the table and
we made it out of ETFE and we made it an insulated green house and we made it have its natural
light and we made it sound good so it was again, the structure, my bit was undetermined
at this stage. But we did know we needed two layers of these
ETFE pillows because to make ETFE which is a nought point two millimetres thick plastic,
it’s really just a polythene bag, into something that can actually do anything you have to
inflate it with air and make it pressurised. So you make these pillows and we knew we need
two layers of them to keep the heat in at night otherwise all the heat we gained during
the day was just going to go out again during the night.
So at that point I looked at this and said aha that means there is a space between the
inside pillow and the outside pillow, where I could put my structure that is neither inside
nor outside. And then I thought well how does that structure
want to inhabit that space? It is not a question we normally ask. We normally ask how the space,
how the structure enclose space for human habitation. How do we build walls and roofs
and things? I suddenly thought how does structure inhabit
space and I realised I’d never questioned, never written before, I’d never heard anything
at University or afterwards that answered that.
And then I saw this photograph which I took to be some piece of biology, an organic material,
and I said aha that looks to me like structure inhabiting space, that’s what we are going
to do. That was a great aha moment then follow that
with a mmm. But what is it? And how do you define it?
And how do I work it out? And then the magic 2003 was really the early days of the internet
and I found of course the World Wide Web can help you in all these matters.
So I went out and did some research and I found out that Lord Kelvin in the 1890’s had
asked the question “how do you sub-divide three-dimensional space in the optimum fashion
into equal volumes” and he came up with this thing called Kelvin foam, which is a truncated
opti-heaven as the optimum way of doing it. And all his friends and colleagues had a look
at it and they all tried as well and none of them could do any better so they sort of
gave up and for 100 years you know that was the answer as to how you sub-divide three-dimensional
space. But it didn’t look very exciting to me and
it didn’t look very like my photograph either. I then found a Belgium physicist at the same
time a fellow called Plato who was looking into soap bubbles and actually an infinite
array of soap bubbles will also be the answer to “how do you sub-divide three-dimensional
space” because the surface tension in the bubble will try minimise the surface area
which means it’s the same challenge. And he’d observed, Plato had observed that
soap bubbles always come together, three films at 120 degrees and at the end of a line, four
lines come in and they are at a tetrahedron angle of a 100 and, if I can remember it is
either 104.9 or 109.4. I think it is 104.9. And so I said that’s the answer isn’t it?
All you have to do is draw those lines and keep drawing them you know in a 3D CAD model
and you will come up with the answer. Well of course it doesn’t work like that otherwise
somebody would have worked it out a long time earlier.
And lastly, I found that a fellow called Professor Weaire and his PHD student Doctor Phelan in
the Trinity College, Dublin in 1993 about 100 years after Kelvin had come up with a
formation of geometry which was more efficient than Kelvin foam.
And it’s made of these two polyhedral that you see in front of you collected together
to form the molecule on the right which then repeats.
It’s mainly made out of a pentagon with the odd hexagon in it.
And what I found is that if I took a very large block of Weaire-Phelan foam and then
cut it at a skew angle, and it was cutting it at the skew angle that was the clever bit,
or the odd bit, so if you go across the top here from left to right and then the middle
from right to left and at the bottom you will see how we did it.
We took a block of the foam at a skew angle, we chopped out a fifty metre height of it,
then on plan in the middle we chopped out a 200 metre square box and then on the bottom
we hollowed out the spaces, the volumes that we wanted to occupy, the actual halls inside
the centre itself and you end up with this, a wonderful structure.
And this is you know, this is sort of really new to us because all that was done inside
a machine. It wasn’t done on the back of a napkin.
It wasn’t done with paper and pencil and it came out with 24 no 22,000 elements joined
together at 12,000 nodes or intersections. And we said that’s it that’s what we want
to do and it’s going to be a structure like no other, it produces a wonderfully random
pattern for the pillows to go on, on the surfaces which is just what the architect liked.
The only question now was how do we show the judges that this is what we are putting forward
so we said that’s easy we’ll just make a model, like a physical model and actually as you
might realise by now this isn’t going to be an easy thing to make a physical model of
so we said that’s, that’s ok because these are these things called rapid prototyping.
So what we will do we will make one of these wonderful models using a computer driven rapid
prototyping machine never been used in the architectural engineering world before but
common place in the car and aerospace industries but no one had ever made a model with 22,000
different bits in it. They were used to making one piece that was
a complex shape. It took us four weeks eventually to get our
data in the right format to get the model to work and we made this model 24 hours before
the deadline for the competition. And we shipped it from Melbourne to Beijing
overnight where the Chinese had hand made the surfaces which they then glued onto the
model. And I’ll never forget one of them I got a
phone call saying the north wall doesn’t fit ok what’ll we do?
And for some reason, I have no idea why, I said what happens if you turn it around ok
and luckily that was the answer and it did fit.
And we made the model and submitted it and fortunately won the competition which is,
which is great because we won from the jury which is the official judges but also the
Chinese had put it on the internet for public voting and sometimes that had happened before
and I’d normally cheated a bit and asked everybody in Arup you know to vote for the Arup scheme.
In this case we won by a million votes so I don’t think the Arup voting system would
have made much better. Then you get this incredible euphoria when
you win a design competition but of course to win a design competition you normally push
the boat quite a long way away from the shore and then the next day you wake up and you
think aha. Now we have to make it work ok? So from a
structural point of view I built then an analytical model. You might think I should have done
this before but we were so busy making the physical model to convince the judges that
we hadn’t thought about the analytical model. I mean it looked like a structure, you know,
it felt like a structure, if you like it smelt like a structure but was it one?
And the first time we built an analytical model I couldn’t make it stand up.
If the elements were put in rather large you know to make them strong enough they were
also too heavy and if they were put in smaller than they were too weak and the thing fell
down. So again in this sort of brand new digital
age we invented a whole new analytical process that sorted it out for us and what that meant
is what we did was simple, it seems trivial but it you know it was one of those things,
one of those breakthroughs. You put every element in rather small, you
analyse it, you find out the stresses in every element and then compare it with literally
with the code of practice of China and not some arbitrary number but the actual code
of practice of China, if you didn’t meet the code then make it bigger by one small increment
yeah and if some reason it seemed to be larger than it had to be make it smaller by one small
increment. Don’t try and guess the actual answer just
move it in the right direction slowly. And what we found after a lot of experiment
was it would converge as you can see here after about 20, 20 cycles it converged on
a stable answer which also I am glad to say proved it was also an efficient structure
at about 5,000 tonnes of steel. This picture shows you slightly shady different
colour there and one of ten different sizes. We only use ten different sizes in the whole
model and you may be able to work out now why I couldn’t guess which one went where.
Actually the thing is so highly redundant for the structural engineers in the room that
you could come up with an infinite number of solutions that also works.
It didn’t matter which one you used as long as it would then produce a set of calculations
that would satisfy the Chinese authorities within the linear elastic state it would comply
with the Chinese code. And every time you ran it you got a different
answer which was rather nice you know so every day we got a different structure and so we
just said one day ok we’ll have that one. Ok — moving on.
This shows its dynamic properties. It is a completely framed structure; there
is no triangulation in it so it relies entirely on the moments at the end of each element.
And what’s really strange about this is not, these are the first four motor vibrations
so the top two, left and right, not surprisingly are very similar and have a frequency of about
one hertz and because it is a square thing in the end you know so it is doing roughly
the same thing. But what amazed me is the bottom two, the
vertical and the torsional are the next two modes and they’re also around one hertz.
I still don’t know why, I can’t tell you why, but what it meant was in an earth quake and
earth quakes are the major dominant loads in Beijing, every single element played its
part in absorbing energy or could play its part in absorbing energy from the earth quake.
So it actually turned out to be the most earth quake resistant building in the world probably.
I can’t prove that I can tell you it takes more than one gravity sideways and it’s still
standing up quite easily. It just forms plastic hinge after plastic
hinge after plastic hinge after plastic hinge until it gets to 44,000 of them before it
gives up. Having done all the sizing of the elements
inside the computer we then wrote a piece of logic that said well we will make the nodes
spherical because that’s an easy way of elements coming together and we will size the spheres
according to the size of the elements coming into them, and we’ll write a rule and therefore
we’ll develop all the spheres as well and then all the elements get cut back until they
meet their spheres and then we have you know what we now call a bin model. We have a fully
defined piece of structure. So far it hasn’t been touched by anybody.
It hasn’t been meddled with manually if you like and we got it down to we could re-do
the whole structural process if, for example, we wanted to make the building smaller, which
we had to do several times or add a doorway or do something to it in three days.
So we could go three days from changing it to having a new set of construction documents.
The construction documents could be portrayed in lots of different ways.
Up till now I have always said there should only be one set of contract information for
fear of there being a contradiction so it was normally the 2-dimensional drawings with
the contract information. Here we said, well actually, as this is just
a set of data that hasn’t been touched by anybody then we can represent it any way we
want. So we could represent it as you see on the
left here as a wire frame model with a lot of tags on it and a whole set of data saying
what each tag meant or we could represent it on the right hand side as a set of 2D information
or on the bottom of the right hand side, you can barely see it I am sorry, a bit washed
out, but 3-dimensional views of the actual connection details for example.
And you can visualise it so this isn’t what the architects normally call a CGI, you know
an artificial if you like of visualisation of something where a lot of work has been
done in photo shop to make it look nice. This is actually just a view of the construction
documents and it was the first time we’d done this so this is we are now just into 2004.
But there was some magic in the original geometry and that is that all the, even though the
tube sizes were different throughout the building the geometry repeated because it would come
from that piece of Weaire-Phelan foam that repeated and so we said that the way to build
it was to make a jig which would always be a fixed jig and you make up these little four
legged elements and then on site you bolt them together and as long as you bolt the
right ones together in the right order you get the structure you first thought of.
But at the time we said that looks like a bit of hard work, why don’t we just make lots
of tubes and lots of balls and a big scaffold and we will weld it together? And they did.
And I have no idea whether they welded the right one to the right ones. None whatsoever
but because actually and I say that flippantly but because of the huge redundancy in the
structure it doesn’t actually matter. You formed plastic hinges wherever you needed
to and it would re-distribute you know, the strength was there somewhere if you will.
Actually I think they probably got it right, they took it very seriously.
And then eventually a year later they took the scaffold out and we’d be able to see what
we had constructed. This is the inside of the leisure hall that you didn’t see during
the Olympics it was still not fitted out and then it was finished.
So I went, I was invited to the official opening on Australia Day in 2008. I got the invitation
at 5:00 pm on a Friday that the official was going to be at 9:00 am on a Monday but fortunately
I managed to get there. One of the other things we did is to get the
heat and light balance right. All the ETFE pillows were covered with a silver
dot pattern but we varied the density of the dot pattern according to how much light and
how much heat we wanted into that particular space in the building.
You can see here that when the lights behind the building you see through it you get some
transparency and here again the same thing. But as the sun comes round on to the face
of the building it goes this incredibly metallic colour instead so now all you are seeing is
the silver dots. They are reflected back at you so it’s a bit
like the Sydney Opera House; it changes its mood and its feeling according to the lighting
conditions and what you get before it. Which wasn’t something I must say we totally
predicted but it was still quite nice. And then we went inside and inside the main
pool hall we were actually only getting 5% daylight because this television company wouldn’t
let us let in more than that and they said if it was any more than that we would black
it out anyway and use our flood lights because they’re worried about controlling lights for
television. A bit like our camera at the back whose spotlight
me to make sure I can be filmed which is a similar sort of thing but actually 5% daylight
is tonnes if you’re inside it will make you feel as though it were in natural light and
bright light. This I think was my favourite space this is
just a café in one corner but it had a real sort of serene calm feeling, almost spiritual
and this is Mr Phelps winning his 7th Gold Medal.
Forty-five world records were broken in the swimming centre in Beijing and I to this day,
I will uphold the idea that it was because it was such a beautiful place to be but of
course the athletes performed so well and it was nothing to do with the shark-skin suits
that they were wearing. And then this is the bit you didn’t see at
the Olympics this is the leisure centre so this is the legacy, this is what the people
of Beijing get to use every day now. At one time the Beijing government said actually
we don’t want to make it into a leisure centre, we’d rather make it into a posh restaurant
for because we think it’s so good it should be a very expensive to go into and we pleaded
with them that we would much rather that it were for the people of Beijing and they acquiesced
which is great. So there we have it, the two form this gateway,
I think, if you think about the Olympics I don’t think you would remember any other buildings
really than these two. There is actually a building right next door
the main convention centre the main indoor arena which is larger than either of these
but you probably can’t remember what it was. So I got three slides in amongst these that
talks about projects that sort of pointing out some, I guess some of my approaches to
life or approaches to design so the first one is, at Arup we say we shape a better world.
That’s our strap line if you will but what do we mean by that?
And for a long time I thought well it actually just means that we’ve got to make the world
sustainable. Now I don’t back down from that at all we
do have to make the world sustainable but sustainability is a lot about reducing impact,
you know reducing environmental impact, reducing financial costs, reducing social impact.
That could produce many different worlds actually that comply with that and which one do we
actually want? So what about the benefits? What are we actually
trying to do as well as being sustainable? Mind you, it is about improving the world
for people you know and there is various, there is tonnes of different levels you can
look at that, you can make people safer make them healthier, give them more functionality,
more amenities but ultimately it’s also to inspire them.
We want to enjoy life surely we want out built environment pleasurable. To be delightful
so in the end I short circuit all of that and say delightful efficiency.
Delightful maximise the benefits, efficiency minimise the costs whatever they might be.
So this building I have already introduced to you.
This is the Bird’s Nest Stadium in Beijing. When I look at that I have no doubt at all
that it’s the most beautiful stadium ever built in the world.
But unfortunately it was also quite expensive. It uses an awful lot of steel to make it work
because it is a sculpture with a structure to hold it up if you will.
It is not really made by intense collaboration between engineer and architect trying to work
it out how to do both at once. So I sat down with my best friend Philip Cox
and did this competition for a stadium in Durbin for the world cup, for the soccer world
cup and you might notice that it never got built.
It wasn’t part of the world cup. I still haven’t got over losing this one so I am going to
tell you about it instead. So this is about how an engineer and architect
can try and come together and trust each other enough to try and work out how a form will
work both as structure and architecture. It’s a pretty intense and trusting sort of
arrangement because, particularly for Philip, he has to trust me that when he comes up with
something he likes the look of and I say that doesn’t really work as a structure then I
am right and then I am acting in his best interest and genuinely trying to find something
that will work as a structure and look the way he would like it to look.
So anyway after a while we came up with what we thought was a really you know a really
beautiful building that also worked highly efficiently and I’ll just for a moment describe
how it works. So if we were to work like the Birds Nest
Stadium which are really just these big deep trusses spanning across it this is a cross-section
and it shows something like a nine metre deep truss cantilevering 70 metres.
It shows you have got tension in the top cord and comprehension in the bottom cord under
a vertically downward lobe. Well when you do that in 3-dimension you have to put them
sort of 12 metres apart or thereabouts, you have to put spanning elements between them
to hold up the cladding. You have to keep the compression cord stable laterally so you
add another layer of structure at the bottom. It’s now looking pretty nasty so you probably
add a ceiling underneath that can be the bird’s nest house and you end up with a lot of steel
and a bit of a jungle. If instead you take exactly the same principles
and smear them out into 3-dimensions and now you offset the bottom cords from the top cords
you can now have a structure to where all the structure is carrying the planning. Where
the structure is also auto stable, that is, the difference in curvature and the offset
keeps everything from buckling and you literally take out 60% of the weight by going from the
truss structure to this one. And in our case the brief was for a stadium
that could hold 70,000 for the World Cup and then go down to 50,000 afterwards and we could
put the 20,000 extra seats up into those humps in the roof that wouldn’t have been available
to you if you had done a truss with a ceiling on it.
So I am still, oh and the last bit is of course, is the inwards curvature of the wall, which
is part of what we wanted it to look like also gave you exactly the right amount of
floor place of each level for that particular stadium brief.
Often in a stadium you get a problem that the floor plates get bigger and bigger as
you come down but actually there is no more facilities that you need at the bottom than
you need at the top. But as I said unfortunately we lost that one.
But instead we did the baby brother. This is AAIMI Park in Melbourne. I love this
photograph of AAIMI Park because it looks like a CGI but it’s not, it’s the real thing.
This is what we built. The principles the same, it’s a much more
modest design. It’s only a 25,000 seat stadium with a small
roof. But we did do is use parametric modelling
to help us make it as efficient as possible so on the left there you see a program called
Catia and the red line links the leading edge of the roof together.
And all the white lines are rule based and follow the red line so we set up a whole lot
of geometrical rules that operates in the red line so we adjust the red line a bit and
we mil, the structure model pops out we size it automatically like we did at Beijing using
the same piece of software and the architect gets to look at it and says do I like it or
do I not like it, does it look better? And we also looked at the panelization of
the façade, the cladding, are we getting more or less repetition, is it more efficient
to clad it with this shape or the other shape? In theory you can link all these together
and use some kind of genetic algorithm to sort out the most optimum solution.
In reality I find it’s better to do it by hand actually so adjust the red line, look
at the different outcomes and then think about how else you should you adjust it to make
it better. You know, which is more important, making
it look good, making it repetitious, making it less steel and eventually we decide on
something. The other advantage as I said before in a
way is that this is a CGI this is a rendering you know we made of the building before we
built it and this is the building after it was constructed so you get a pretty good idea
now what you’re going to get before you go into the physical world.
Here we see it being used and the same idea of the seats and the humps and in this case
we likened it to a club you know where you might sit in your booth at the back, you might
have your favourite piece that you always go to that you occupy.
It breaks up, the inside of stadiums can be quite characterless, they all look the same
once you’re in them you know, we make them different from the outside, not necessarily
from the inside. This again is one of my favourite shots because
again this is reality. This is it sitting on the river in Melbourne
and then lit up at night and another thing Melbourne is fantastic because you can, you’ll
be able to hear as well, you can see your stadium from the city, you can see what is
happening and you can decide you know, am I going to go and watch a match tonight as
you come out of work, or am I just going to have a drink there or am I going to walk around
the park – great place. So here is my second little sort of philosophic
piece and that’s about design. When I was first made an Arup Fellow, 10 years ago, the
first question I was asked is ok how do you do it? I shrugged my shoulders and said I
don’t know, that’s what I do, I am not an academic, I don’t think very much in those
sorts of ways, I just you know do what I do. And so it made me think you know and so three
or four years later I decided that this is the way I tend to go about a project you know.
The first thing is to think about what so you want to achieve, not as a structural engineer
but what should the project achieve, what outcomes does your client really want, it’s
often not written in the brief actually, you often have to go and talk to people to find
out what they really want. And also of course, stakeholders, it’s not
just about what your clients want but what do the end users want, what does the community
want, what do people overall want? The second one is a sort of what I think of
as a design actually being is to challenge the status quo, to not accept what has been
done before is the best that can be done. It may be, but you don’t accept it initially,
you’ve got to say, can it be done better. It doesn’t matter what it is. It could be
a spreadsheet, it could be a project management plan, it could be how you write an email,
it doesn’t matter, all of those things when you do them, can they be done better?
The third one as I said before is trying to improve people’s lives, and in particular
I think to get an emotional response on a human scale.
I remember I worked for a wonderful engineer called Peter Rice, when I was young, who unfortunately
died young like George I guess. Peter said to me though, he said Tristram,
it doesn’t matter if your structure is wizardry and wonderful, what matters is how people
will respond to it. How will they think you know what emotional
response will you get from the people who visit it.
Then there is as I have already said you make it as efficient as you can, you make it as
delightful as you can, and lastly and most importantly for us in our industry you have
to deliver it. It’s no good just ending up like Durban did
you know in the ether, it has to come out and become real and that’s the hardest challenge
of the lot. It has to be built.
For this project I was asked to include some more international projects so these are projects
I have been working on recently that haven’t always been completed.
So this is about an airport in Kuwait with Norman Foster as the architect.
The question here is what actually are you trying to do in Kuwait?
What’s Kuwait about? Kuwait is about hot heat and dirt or dust, desert storm, it’s about
solidity and trying to find shade and the feeling of shade even when it’s not, or the
feeling of cool rather that comes from shade and mass and masonry.
This is the plan of the airport super imposed off Hong Kong’s harbour so it wasn’t a small
challenge that we were faced with. This airport is 1.2 kilometres from tip to
tip with a triangular element. Yet, Fosters in their wisdom decided it should
be made of concrete. So we were faced with a challenge of, this
is just one arm of it, of a concrete roof probably ten times larger than any other concrete
roof that’s ever been built. With up to a 60 metre cantilever around all
its edges and a 48 metre span between it and then how do you do this efficiently?
So we came up really with a schema you see in front of you that the bottom is the set
of arches and ribs out of post tension concrete so if you like the opera house construction
or bridge, big segmental bridge construction and on top of it the idea of this light weight
concrete shell, but the light weight concrete shell is not easy.
In in situ concrete it will be 300 millimetres thick which could actually weigh an awful
lot. You’d have, every single panel is different,
I should have said all the shells are different. So the formwork would have been horrendous
and then it would have fallen apart under thermal load because it’s so big.
So in the end we came up with this idea of using fruit boxes, we call them, so we call
this fruit box engineering and it was simply the idea that if we make panels of, and I
called these concrete panels for Foster’s sake but for me they are hybrid panels because
they are steel frame with a concrete base. All the steel is vertical, vertically set
in real life and flat and later cut so as to get them as accurate as possible, four
pieces. Then we put them on a formwork and we cast
the piece of concrete in the bottom. And then as you see at the bottom there you
produce these cruciform elements also from laser cut steel which you then just bolt everything
together and in theory it’ll all work as long as everything is made accurately.
And this is an image therefore of the central piece, probably the simplest bit of how it
will all go together each piece is about 4 metres square, the fruit boxes to give you
a scale and the concrete is only 130 millimetres thick.
That shows you the more complex piece around the edge with the 60 metre cantilever but
it was applying a ruthless piece of logic if you like, a piece of process across an
analogue idea. Here’s a fruit box and this is its clever
bit. The clever bit is that concrete will carry
quite a lot of compression as I think we all know and therefore in compression it all sort
of forces itself together if it gets hot. But if it pulls, starts pulling itself apart
the concrete won’t take much tension so what happens those steel side plates flex and bend
and allow it go away so it was all about balancing stiffnesses.
How do we get the right amount of in plane stiffness so the shelves worked the right
amount of bending stiffness so they stayed stable and didn’t buckle in compression but
the least amount of tension stiffness so we could release the tension forces out of the
concrete. It was quite an ask and we ended up doing
full dynamic, not dynamic, but using a dynamic non-linear program to analyse as you can see
it, at this level, every bar of re-enforcement, all the welds, all the steel and in a non-linear
fashion pulling it and pushing it and bending it just to make sure that all those stiffness
parameters were actually what we were going to get.
And there you see the final, an image of the final product. This is only out to tender
as we speak so hasn’t yet been proven to work, this is uhm, but it has been fully designed.
Second to last is this Singapore sports hub so this is a stadium for Singapore.
Singaporeans are not known for being sports fans but they wanted a national stadium for
their national identity. It had to be a multi-purpose stadium so one
of its attributes is it has an open and closing roof so you can use it in the rain and also
so you can keep people cool in the heat of the Singaporean summer.
The schema is Arup’s architects and engineers so the scheme we came up with is this enormous
dome that career spans across the seats that provide a moving piece at the top, a solid
piece at the edge of the seats and then an open louvered piece at the perimeter.
And again to give you scale this is a 300 metre diameter dome, I am told it’s the worlds’
largest dome, I haven’t done my own research but I am told it’s the worlds’ largest dome.
And of course it can be open, so you can use it either in close mode or you can open the
roof as you see here which, just remember that shot because if, the structure I am going
to talk about later is highly dependent on this problem that you’ve got a big weight
that can be in the centre or it can be separated and then these naturally vented spaces at
either side. So to keep people cool in summer we provide
under-seat air conditioner if you like but we were not going to try and air condition
the whole volume its’ enormous, we are just going to produce local cooling.
To do that though and at the bottom there I’ve got a picture of a CFD, Computational
Fluid Dynamics, of all the people in their seats on the left, then the middle image is
the bottom tier, next to the right is the middle tier and the far right is the top tier.
What you can see in the far right is its beginning to get warmer and the reason it’s beginning
to get warmer is there is radiant heat coming in through the roof so the critical part for
the fixed roof is to insulate it as well as possible and to reflect things but the critical
for the moving roof, the top bit, is to make it as light as possible, is because it’s this
moving load that will crucify the fixed roof otherwise.
So it’s this delicate balancing of everybody in the room talking about what do we want
out of each component, how do we make it work? The moving roof is actually clad in ETFE like
Beijing to keep it as light as possible and then the outside is louvers just for shade
for the external concourses. And this is a rendering of the outside so
you can see these components so you can see the pillowy shape is the ETFE clad moving
panel then the triangular shape if you like with the lines across it is the fixed roof
which is kalzip aluminium cladding with a lot of insulation underneath it and then the
louvers down below for the external concourse. And this is the primary structure but it’s
not the whole trick this is part of the primary structure so it’s trusses. The trusses there
vary in depth and width from the centre of the building where they’re deepest to the
perimeter of the building where they’re shallowest and this comes back to this human reaction
bit which I’ll talk a bit about later. But there is also these bit diagonal trusses
and you are looking at it and probably thinking why are they there?
Well at the bottom of all these trusses is a ring beam that holds it all together but
all the steer is in compression the ring beam is in tension.
But the ring beam cannot cope without a balanced load.
It can only cope with a uniform pressure pushing outwards on it and what the diagonals do then
is as this moving load changes it re-directs the moving load outwards so when the roof
is open it pushes towards the end and when the roof is closed it allows the stresses
to come down in the middle. That’s quite complicated and I haven’t got
a decent image to show you, but I hope you’ll get it, then across that is a set of secondary
trusses and a set of louver trusses, lots of different geometry being used in different
places to get different responses or different impacts.
And of course here you see that moving load, that’s the moving roof in its open position.
The secondary trusses aren’t shown otherwise it would look just like a jumble of lines.
And this shows you the deflections of the roof and without the moving roof shown in
some of the images and with it on the top right, so you see the top left is the dead
weight deflection of the whole roof without the moving panel.
The top right is what the moving panel does to it when it’s closed, the bottom left is
what the moving panel does to it when it’s open and the sections in the bottom right
show you they’re different so it goes down in the middle when it’s closed and it goes
down on the sides when it’s open and that was the thing that was really challenging
about this roof. And here you see the louvers now complete,
the louvered zone down at the concourse, now I think, I hope you see the benefit of tapering
the trusses they’re now only 2 metres deep at the perimeter, they’re 5 metres deep for
buckling reasons up at the top centre to carry the moving panel.
But this brings them down to something that’s more of a human scale where people get to
meet them and interact with them. And here you see the whole structure, last
week the fixed roof was completed and the prop so we’ve now got the worlds’ largest
dome now actually exists. This is my last slide which is about the impact
of IT in the Built Environment you might have noticed that I talked a lot about the virtual
world. I think this revolution, even though it has
been going on all my life, my professional life, has still got a long way to run.
The impact that the digital world has on the physical world through our ability to now
design things absolutely perfectly before they are constructed.
It used to be that every building was its own prototype you only tested it when it was
made and in those days the car industry made physical prototypes and crash tested them
against solid bits of concrete, nowadays both of us can do it in the virtual world without
resorting to the physical world. And we know what we want before we build it.
I would then suggest that construction will become more manufacturing where we make things
in factories all over the world and bring them to site and assemble them because we
know what we want we can predetermine it. One of the reasons we pour concrete into timber
forms on site is to get it right on the spot you know to alter things as we go to make
the holes required for the services to pass through the structure.
But all of that can now be predetermined we can coordinate it all in the digital world.
I can talk more and more about this but I won’t do too much because I am probably out
of time. And in the end it’s the internet of things
out there in the physical environment itself you can have actuators and sensors so you
can get feedback from what people are actually doing and you can change the physical environment
in real time. This is most readily seen in smart infrastructure
so the idea that you can control traffic systems according to traffic flows, you can control
energy supply according to energy demand etc. And lastly if we were clever designers we
would take all the feedback and use it to make our designs better and make our plans
better. At the moment I am ashamed to say most designers
when they’ve finished a building walk away from it.
They very rarely go back and find out how it’s actually used or whether its occupants
actually like it because the myth is almost always better than the reality but we stick
with our ideas, our concept of what we want to have happen rather than finding out what
really happened. This is the last building, last project, back
in Australia, this is in Brisbane, this is 111 Eagle Street, and it’s the tower in the
middle that I am going to talk about. We put it between two very, very good, very
beautiful buildings by Harry Siedler, two modernists’ buildings on the left and the
right. This is on plan the two grey blocks are the
two existing buildings and our site was right in the middle but it was sitting right on
top of the existing car park and right over the existing loading dock which you can just
see with a car in it right in the middle of this slide.
And so we said well either we just you know we sterilise the whole basement in sight while
we carve it up, build a new basement you know and build our building on top or we make use
of what we’ve got. We leave the loading dock where it is, we
put our columns where we can for the building, we put our new core where we can, which is
offset to one side, because of the existing loading dock and then we make a virtual out
of it and see what we can do. Unfortunately, when the core is off centre
like that it no longer works for a 40 storey building in a cyclone zone and to take the
wind loads alone so we decided we also then had to have a perimeter structure to make
the building work against wind load. So what we did is we said that if we start
with a random position of columns, in other words we only put them where we can then why
don’t we just grow them randomly up the building and let’s see what that looks like and actually
it occurred to me that if you incline columns very slightly they’ll actually probably work
to carry the wind load as well. And so that is precisely what we did, we wrote
a computer program that would generate random numbers and produce random sets of columns.
It’s not quite as simple as that. What we said is that from every level let’s generate
a new set of columns and then let’s test it. Let’s say, do we have as many columns leading
to the left as to the right, in other words is it balanced under vertical load rather
than wanting to fall over one way or the other. Is it balanced front to back, is it balanced
torsionally, more importantly does the floor above get a decent amount of support or do
the edge beams get too long you know and we said we’d limited that and we said we want
only an 8 metre edge beam. And then we played with the amount of randomness
as you went up the building so what happens is each time it gets to a floor it generates
a set of columns it says pass or fail, every about, only one in ten thousand would pass
times and then it goes and generates another lot, another lot, another lot and it might
get stuck part way of the building and say actually I can’t find the new set of patterns
of columns, it takes the next lift, in which case just go back to the bottom and start
again. It’s incredibly profligate you know only one
in a million attempts comes out with success but it doesn’t matter because it only takes
minutes you know and then you say ok that’s one, there’s one I’ll put it on the shelf
and when you get twenty of them on the shelf, you go down to see your friendly architect
again, Philip Cox in this case and you say “Do you like any of them Philip? Do they look
any good?” And he normally says no, and so you come back
again and you re-write the program to some slightly different logic you know and as you
can see this is the final one and what we’ve done is make the columns get more random,
more chaotic, more excited as you get to the top of the building because they are carrying
less load by then so you can. Down the bottom they are quite strict, they’re
quite vertical, they’re quite you know, they’ve got to have a five degree average lean to
take the wind load, after that they can be you know more upright.
This is the Cox drawing of the same building I am glad to say, here they coloured coded
the columns according to their size so you can see in a way that it does actually work.
The columns are behaving the way we’d expect them to.
And for the structural engineers this is a, on the left the vertical load diagram, on
the right the wind load diagram showing the columns are doing what they are meant to do.
They are carrying more load as you get towards the bottom relatively evenly and on the right
hand one, they are barely going into tension on one face and they are taking the compression
on the other. This is my favourite drawing I think because
this is 2008. On the right is our revit model and on the
left is the architect’s revit model winded and for once they are the same thing ok?
Only time in my life so far, we’ll get there. And here it is built.
Here it is in Brisbane, it was the only high rise building in Australia to not stop construction
in 2009. DPT, our client had the courage to continue,
and by the way we were open with them and didn’t rely on the competition, we said we
think this is a building you will like, it will cost you $6m more you know and they said
ok we’ll have it, we’ll do it. They’ve done it, it was fully tenanted when
it was opened so they had the courage of their convictions to continue construction through
the recession with a modest hiccup we had in Australia. I think now we might be having
a recession unfortunately. And there it is lit up at night.
So there, ladies and gentleman, thank you very much.