Transcription du balado: Vision for a Modular Antarctica (en anglais)
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Alex
Antarctica is officially the coldest place on earth
Jane
Satellite data has recorded temperatures as low as minus 92 degrees centigrade at the East Antarctic Plateau
Alex
Average temperatures vary from -10degrees on the coast to -60 degrees inland, and winds have been recorded as reaching over 320km per hour
Jane
Making it one of the most inhospitable places on earth
Alex
And yet the continent is home to around 4,400 researchers in the summer and just over 1,000 during the winter.
Will Parker
You do kind of feel that as a person when you go there that, well, this is a fascinating place to visit, but you kind of are quite aware that people don't really belong there. And I guess that is sort of the fundamental importance of buildings there. Because it's not a place where people can really survive without, you know, the technology and the infrastructure that humans are able to create.
Jane
At New Zealand's Scott Base on the volcanic Ross Island, most of these critical buildings haven’t been upgraded since the 80’s.
Simon Shelton
I've been especially through winter where you can hear the building move. It sounds like a gun going off, it's cracking you know, the timber piles or the insulated panel structure moves with either the humidity or the temperature.
Hugh Broughton
And the winter lasts for about eight to nine months, there's only going to be around 15, maybe 20 people on the base for all that period. And they're going to suffer from extremes of weather they're going to suffer from three to four months of total darkness and a real sense of isolation.
MUSIC
HELLO AND WELCOME
Alex and Jane
Hello and welcome to Engineering Matters, I’m Alex Conacher and I’m Jane Sophia. In this episode we’ve partnered with WSP to learn about the redevelopment of Scott Base in Antarctica, and the challenges that come with building in one of the most isolated and extreme environments on earth.
Jane
Antarctica was one of the last places on earth to be discovered.
Alex
From as early as the 5th century a land mass is shown at the bottom of some maps, the area is named Terra Australis Incognita
Jane
Terra Australis Incognita or Unknown Southern Land was only theoretical at this time, and based on the belief that if there was a land mass at the North pole that must be balanced out by one on the south pole.
Sounds of rough seas
Alex
It wasn’t until 1773 that James Cook and his crew crossed into the Antarctic circle, but still there was no sighting of the Unknown Southern Land.
Jane
It took 50 more years before a Russian expedition became the first to see Antarctica and just one year later American Captain John Davis became the first to step foot onto the ice of Antarctica.
Alex
What ensued was a race from explorers to conquer the conditions and be the first to reach the South Pole.
Jane
One of those explorers was Robert Falcon Scott, whose first Antarctic expeditions in 1901 had broken the record for farthest south anyone had been.
Alex
And in 1910 Scott set out again to try and reach the South Pole, but before he left from New Zealand to head to Antarctica, he received word that Norwegian explorer Roald Amundsen was setting off for the south pole too.
Sounds of howling winds
Jane
Scott and his team's march to the South Pole began on 1 of November 1911 and they walked for over two months through freezing conditions, more and more men turned back until just five of them travelled for two more weeks and made it to the South Pole.
Alex
And what they found there was a letter from Amundsen dated one month prior. Scott and his team had been beaten.
Jane
Scott’s reaction has been immortalised in his diary. He wrote "The worst has happened, All the day dreams must go, Great God! This is an awful place".
SAD MUSIC
Alex
On the walk back to meet their crew conditions turned even worse, the temperature unexpectedly dropped to -40 degrees Celsius. They were trapped and knew they weren’t going to make it.
Jane
Scott and his crew wrote farewell letters to their families and Scott even wrote one to the public in which he said, “Had we lived, I should have had a tale to tell of the hardihood, endurance, and courage of my companions which would have stirred the heart of every Englishman.”
MUSIC
BODY
Alex
Scott Base was first set up in 1957 to support the Commonwealth Trans-Antarctic Expedition led by Sir Edmund Hilary. It is named in honour of Robert Scott and located where he and his team began their expedition.
Hugh Broughton
Scott base is in a really interesting location because it's on Ross Island, which is where the great explorers, Scott Shackleton Amundson all set off from that part of Antarctica in their attempts to get to the South Pole. So it's, there's a lot of history around and about. There's actually even a historic hut on the site of Scott bass that was first put there in 1957, by Sir Edmund Hillary
Alex
This is Hugh Broughton, the lead architect on the redevelopment project and a world leader in designing buildings for extreme environments.
Jane
The base has continued to be developed further over the years and now consists of 12 buildings on the side of a hill connected by walkways.
Will Parker
The existing buildings are kind of interesting, because they've evolved over time, they've been extended and they've been kind of joined together by a series of walkways. So you don't have to go outside from one to the other.
Alex
Will Parker is a technical director at WSP, based in New Zealand.
Will Parker
So buildings are incredibly important, because they're kind of that sort of fundamental requirement to preserve life, keep people warm, you know, that if, if your systems go down, your buildings get cold, people aren't going to be able to survive for that long.
Simon Shelton
So the current base was largely built over a number of years through the 80s 1980s. It's a collection of 12 buildings, they're built to be built based on function, and to a degree, ease of construction. So they follow the contours of the land. And they are built separately and connected by linkways. So those link ways have stairwells. So these I guess, these compromises in construction that made it easier, also have challenges in operating. So when we need to, say move food or science equipment around, you have to walk quite long distances up stairs. And it's, it can be through different eras, and building types. So things like the claddings are different in some buildings and some are better insulated than others. And so it's a bit of a mix match of different construction types.
Alex
Simon Shelton is Antarctica New Zealand’s Senior Project Manager for the Scott Base Redevelopment, and he’s seen for himself that Scott Base is in need of repair.
Simon Shelton
And so we're starting to see some of those issues now, where insulation is failing, paints flaking, snow will accumulate on the roof, and then start to, as it warms up through the summer period, will leak through and then start to compromise the weather tightness and warmth and inability for the building to maintain the thermal mass.
Jane
Simon is a veteran of Antarctica having taken over 20 trips to Scott Base.
Simon Shelton
So to go there, I mean, it's, it's always really special despite going, you know, several times, sometimes one season.
Jane
Simon has also done a couple of trips to Scott Base in the winter.
Simon Shelton
Through winter, it's a smaller crowd, you're there for a much longer duration. The last flight in summer is typically around the end of February, and then the next flight that will come in is about the 20th of August. So my first winter we literally waved goodbye to that group at the end of February and we didn't see anyone until August which was a really foreign feeling you just you don't get that anywhere else in the world. And it really did make you feel quite isolated but also brought the team very close.
Jane
With the buildings at Scott Base in need of repair the New Zealand government, who own the base, put forward £176 million for its redevelopment.
Alex
But before you can get to the difficulties of building in Antarctica, WSP and Antarctica New Zealand had to deal with the logistics issues of getting materials to Scott Base.
Karissa Hyde
So there is one shipping time period per year. So every year in sort of January, February, we work really closely with the American base, right next door to us. And we have a joint logistics pool. So, we share resources on all sorts of things. But so we have one bunch of ships, basically an icebreaker that comes in at the start of January, followed by two or three supply ships. And that's it for the year in terms of shipping. So anything big. Or basically anything where you're organised enough you want to get on that ship, because it's a lot cheaper.
Jane
Karissa Hyde is the construction manager for Antarctica New Zealand. And along with the limited shipping period, Antarctica also spends 4 months of the year in 24-hour darkness with a nine-month winter where temperatures drop below -50 degrees Celsius.
Alex
To limit the amount of work that will be done in Antarctica the team decided to pursue prefabricated modular design that could be completely built in New Zealand before being taken to Ross Island.
Simon Shelton
So I think we're taking it to the extreme for this build.
We are building whole modules and shipping them down on a really unique vessel called a modular carrier class vessel that's ice strengthened. And these modules are really large, so there are over 1000 tonne each module and there's eight of them. Each module is around about 24 metres by 24 metres by 18 to 20 metres high. They have four structural bays at six metre grids, and they are far more rigid than a typical building even more so than a building like a hospital that has to have a high degree of resilience for natural hazards such as earthquakes. So they're really strong buildings they’re lifted up using these things called self propelled modular transporters and wheeled onto this large vessel that has a deck that 's around about the size of a football field. And, that heads down from New Zealand to Ross Island.
Jane
Once at the island, the modules will be rolled off the ship and put into place before being connected.
Alex
To further reduce the time spent on construction in Antarctica all the modules will be fit with working utilities before leaving New Zealand.
Simon Shelton
So we will fit these modules out as much as possible. So they will have all of the services and then we'll run them up with things like water production will test all of the power and data and communication networks. So essentially you can operate the buildings in New Zealand, before we send them down. So yeah, it's quite an extreme case of modular construction.
Alex
Another advantage of taking this modular approach is that it massively reduces the size of the construction team that will be required in Antarctica.
Karissa Hyde
It has the ability that you can build in New Zealand year round, you have a lot less health and safety risks as well. Working in New Zealand, rather than Antarctica, and it also helps with the whole personnel.
Karissa Hyde
The more people you send down, the more supporting people you need to send down and it balloons into a very large thing very quickly.
Simon Shelton
When we take the modules off and position them in Antarctica, there will be around about 80 to 100 people, construction workers, and the vessel may house some that are associated with the vessel operations, they'll obviously be people also involved with things like icebreaking. But it's a reasonably small team, compared to many commercial or industrial sites.
Simon Shelton
And we're planning on around about two months to carry out the module offload and connection of the buildings. And then the buildings will go through a winter and Antarctic winter where we'll essentially stress test the buildings but also the services to make sure that they can stand up to an Antarctic winter and you know, temperatures down to minus 57, 57.5 is our record temperature at Scott Base. So ambient. Celsius, so it does get really cold, we just want to make sure that the building is up to it before we start putting people on there. So we'll actually have two stations running in parallel for one winter to ensure that it's resilient, safe and ready to use.
Jane
The design of the new base had to take into account the prefabricated modular construction process but also the extreme environmental factors.
Alex
And even though Hugh Broughton has been involved in designing several Antarctic projects, Scott Base and its location on Ross Island present some unique challenges.
Hugh Broughton
Scott Base has actually got quite a lot of design parameters, it's next to the sea. There are restrictive existing science installations, there's a road that leads from airfields to the US base at McMurdo. It's a sloping site. It's got very strong winds blowing from the south, but prevailing winds are blowing from the north. And then in addition to that, they had a particular programme because Antarctica New Zealand support expeditions that are generally run away from the base, by scientists from universities, international collaborations, and so on. So it's, it's very much a kind of staging post for science conducted in the field. So that also made it very different from some of the other projects which we had worked on. So yeah, lots of parameters, historical, topographical, geographical, and environmental, as well as programmatic.
Alex
With these constraints in mind and after various visits to Scott Base, Hugh came up with the design.
Hugh Broughton
So Scott Base is designed on a sloping site. And it's three parallel, essentially tubular buildings that are elevated off the ground, that step down the hillside, and are connected by link bridges, so that the lowest level of the top building connects to the highest level of the middle building. And then the lowest level of the middle building connects to the highest level of the bottom building. And these tubular structures have got aerodynamic shapes to them to help channel the wind underneath and keep the snow drift away from the immediate vicinity of the buildings.
Jane
The materials were also carefully considered, as the structure had to be built in the New Zealand summer but survive in the Antarctic winters.
Hugh Broughton
The key consideration here is around the steel structure, which will be exposed in New Zealand and places exposed in Antarctica before it's fully enclosed. So we've got special grades of steel to cope with the low temperature so it doesn't become brittle and shatter. In terms of the cladding, the key thing is achieving total air tightness or as close to total air tightness that we can and high levels of insulation, and we're using a fairly traditional metal composite cladding system, but thicker than it would normally be used, for example, in a more temperate environment, and then we've developed a joint jointing system between the panels, which is truly belt and braces, kind of three or four layers of weatherproofing And to make sure that we keep out not only the cold but the tiny, tiny particles of ice that's called spindrift, which get blown around the site
Alex
All of these elements have already gone through extensive testing to ensure the buildings will be able to withstand the wind and snow.
Hugh Broughton
And we're doing lots of testing on our cladding to ensure its weather tightness, before finally committing to the construction of the main buildings themselves.
Jane
The base has also incorporated many design elements that focus on health and wellbeing of the people living on Scott Base.
Hugh Broughton
So it's quite a balance between supporting the community and creating really nice places for people to get together. Places where they can have fun, like the bar, places where they can be quiet, like a library, places where they can exercise like a gym, but also places where they can be on their own. So everybody who winters or stays for a long duration during the summer gets their own room and you only share if you're there for really a very short period, we've been working with a colour psychologist who's helped us to develop a special palette of colours, not only to help combat the winter blues, but also to reflect the spirit of New Zealand to make people feel more at home with carefully chosen materials as well such as Southland beach which is a timber which comes from New Zealand again, to make help make people feel a bit more home. We've selected furniture which comes from New Zealand, there'll be artwork created by people from New Zealand.
Alex
The design team also worked with lighting experts, to create a daylight simulation during the months of continuous darkness.
Jane
There is another unique factor about the location of Scott Base that impacts the construction, Ross Island is volcanic.
Will Parker
We are building on land, because we're on Ross Island, which is a volcanic island, in the middle of the Ross Sea. So that means we've got volcanic rock. And we've also got scoria. So we've got, you know, what comes out of a volcano, and we've got a slope. So those things all give us quite, in some ways, good foundations, but also some challenging conditions to deal with.
Karissa Hyde
There are definitely benefits to being on the ground, it doesn't move so much.
Karissa Hyde
So most of Antarctica is not soil, like soil in Antarctica is very highly prized. So we really don't want to extend our impact into the surrounding area. So we're trying to keep our footprint as constrained as possible.
Jane
One way that the Scott Base redevelopment is working with the natural environment is how they are constructing the pile foundations.
Will Parker
So we've done some drilling, we've also done some tests piling, so we've gone down and drilled the hole, put a pile in. And then we basically do two things. So we put the pile on a little ground plug. So we pour that in situ. And that gives us really high foundation loads. And then we basically can grout the pile. And that effectively just means we fill the hole up with water, and then it freezes. And that's locking it into the ground. So gives us all the stability we need for the building.
Alex
By using ice for the piles there is no need to bring and mix any concrete in Antarctica.
Simon Shelton
So that gives us good resilience against climate change in a warming environment, means we're well below the active layer. But it also means that we can remove the piles and leave essentially a site that has very little residual demolition waste or materials leftover from the construction and use in our operation down there once we're finished. So we're also considering the deconstruction while we're planning for the construction. We are about 14 metres above sea level, so that considers the tsunami run up risk and sea level rise. So we've taken a really conservative approach to that. And we've worked to a 50 year design life.
Hugh Broughton
So the key is flexibility of design. So with WSP, we've developed a design based around a very regular six metre structural grid. So all the buildings, the length of all the buildings is a multiple of six metres. And we've minimised internal vertical structure so that the interiors could have their fitout changed through the duration, to respond to different emphases in science, potentially even different populations within the buildings. So just challenging that all the time. Looking at designing partition systems, flooring systems, sealing systems, which can easily be reconfigured, has been a key part of the design process.
Jane
To build to a 50 year lifespan is not just about flexibility but also responding to the changing environment.
Alex
Antarctica is particularly prone to the impacts of climate change; studies suggest that the South Pole is warming three times faster than the rest of the world.
Will Parker
So there's a lot of expertise in the science and the science programme that's run by Antarctica New Zealand. So, those experts have had input to the climate change studies that have informed the design. And it's really quite interesting in terms of what will go on with the effects of climate change on Antarctica.
Will Parker
One of the things is obviously, sea level rise. And there are, you know, there is a potential for the sea level to drop because the effect of the pulls due to sea level rise is different to the effects and other parts of the world.
Jane
To deal with the threat, the base is being positioned high enough uphill to be safe from the worst estimates of sea level rise.
Will Parker
But there's also secondary effects of some of these things as well because not every year, but most years the ice breaks out around the coast of Ross Island. And then you get wave action on the shore quite close to the base. But obviously in the future, we expect that probably to happen more. And as more ice breaks out, you have a longer fetch and therefore more wave action. So we've considered that in the design of the base, making sure it's far enough up the slope, but also in some of the facilities that need to be close to the shore, for instance, the water intake structure, because the drinking water is produced by a reverse osmosis plant. So it needs to have an intake from the sea. And also wastewater treated to a really high standard, but does get discharged back to the sea. So those things have to be accessible to the sea. So thinking about the vulnerability of those structures is important.
Alex
The Scott Base redevelopment plan also involves building an expanded wind farm that will allow the base to run almost entirely off of renewable energy.
Simon Shelton
We operate on a shared grid with the US station McMurdo Station, which is about four kilometres away. So the new replacement wind farm is around about four times the size of the existing wind farm. It'll operate off three turbines, and it will also have what's called a battery energy storage system or a large battery bank. That will give us up to 18 hours of runtime when there is no one. And so those things combined, will enable the new station to run on 97.3% renewable energy.
Simon Shelton
All of these things have been considered, especially when our primary stakeholder group are scientists that are looking at the impacts of climate change and Antarctica now. So yeah, it would be naive to dismiss that.
WRAP-UP
Alex
Antarctica remains a cold, isolated and unwelcoming environment for people, but our advancements in engineering, design and construction have allowed for more comfortable living for scientists doing crucial work.
Jane
The Scott Base redevelopment is showing that using creative ways of working with the environment is an effective approach to building in hostile conditions.
Simon Shelton
Hopefully, it inspires other Antarctic research stations to move away from their reliance on fossil fuels. And also to look at things like thermal efficiency within the building. So they don't need to expend so much money or fuel on heating, in looking at things like air tightness, or investing in thermal insulation, or, or thermal mess, or just good design of where you place windows, so you can take advantage of solar gain. So you don't have to use so much energy in your building.
Alex
And the design and construction methods taken on this project will offer insight for other extreme condition projects.
Hugh Broughton
There's no surprise really, that Antarctica is the number one analogue used by the European Space Agency and NASA, when particularly considering human factor design for future interplanetary exploration. I think there are things to be learned about Resource Management, obviously, in Antarctica, producing water is very energy hungry. So ways in which you can reduce the amount of water usage whether that's high pressure water mist, fire suppression systems or low water use fittings in bathrooms or vacuum drainage systems. I think also, that discussion we had around human factor desert design, helping people to cope with the long periods of darkness and isolation, all those feed into design concepts, which could be applied in all sorts of different extreme locations. So I think Antarctica does provide not only a brilliant testbed for out of Earth exploration, but also for the kinds of buildings you might want to find in mountainous areas, or in other deserts.
Jane
100 years ago, being in Antarctica was a battle for survival, now we are creating buildings that not only protect people from the extreme conditions but also makes being in the most remote, hostile environment on Earth, enjoyable.
