The existing buildings are reaching the end of their functional life, and Antarctica New Zealand hopes to redevelop the base to manage risk, bring it up to current standards and support the needs of the scientists working there. We talked to Jamie Lester, a principal structural engineer based in Christchurch, New Zealand, about his experiences as part of the design team.

How did WSP Opus come to be involved in Scott Base?

Jamie Lester: Our involvement actually dates back to the time when we were New Zealand’s Ministry of Works and we designed the first base which opened in 1957. This was established to support the Trans-Antarctic Expedition led by Sir Edmund Hillary. This was replaced in the late 1970s-mid 1980s with the base we see today. Since the completion of the second redevelopment there have been a number of updates to the buildings, however, with some critical services, such as fire protection, not compliant with today’s building standards and increasing points of failure in the building systems and fabric, our client, Antarctica New Zealand, is putting forward a detailed business case to redevelop the base.

We were appointed for the civil engineering and structures design, working with three other firms with expertise in cold climate design – the architects, Jasmax and Hugh Broughton Architects; quantity surveyors, Turner and Townsend; and building services designers, Steensen Varming.

What does the project involve?

The current project is to develop four concept designs for a modern, low-impact facility, based on site investigations and the needs of the 100 people on base carrying out world-leading scientific and environmental protection work facilitated by the New Zealand government.  

We started work last November, and the designs are now with Antarctica New Zealand, who will recommend their preferred option and present a detailed business case, including all the options, to the New Zealand government later this year. If accepted by the Government, we will then focus on developing one preliminary design for the proposed new base.

The works would start on site in 2020/2021 where equipment and materials would be shipped to site. Depending on which design is chosen, construction on site could take up to eight years.

Scott Base is located in one of the world’s harshest environments. What are the key challenges for WSP Opus and the wider design and construction team?

In terms of timings and logistics this is a project like no other. It’s a very short construction season with only a four-month window between November and February, when there is enough daylight and it is not so cold. For speed and ease of construction, the new base will be a modular structure in a similar manner to its predecessor, with as much as possible prefabricated and assembled before being shipped to Antarctica from New Zealand. Because of the ice, the sea isn’t navigable until January (late summer), so all the materials for the following year have to be delivered by then so building can start promptly the next summer.

The foundations are the biggest structural challenge because of the permafrost and the way it freezes and thaws, calling for non-standard designs to cope with the different conditions.  We’re looking at a range of options, including building on concrete pads anchored to the permafrost, and a method using ground refrigeration that’s used a lot in Canada. Actually excavating the foundations is incredibly difficult, since ice is quite elastic, and therefore very difficult to excavate with a machine. It will have to be done using drill and blast techniques and is very labour-intensive.  

There’s also the cold – Antarctica has the coldest climate on the earth! A hot day in summer is -3 OC. When I was there last November it was -5, but that was more like -19 with the windchill. In addition the atmosphere is extremely dry, which affects our choice of materials for the project. In particular shrinkage of timber is a big problem, so any wood used will have to be specially treated.

What are your impressions of Ross Island?

I spent a week there last November getting to know the base, how it works, and what the environment is really like. It’s hard to describe the scale of the landscape. Scott Base is a large complex, but when you land on the ice shelf, it’s just a dot on the landscape on a very small corner of the Ross Ice Shelf.

Scott Base is about 3.5 kms distant from the American base, McMurdo Station. With around 1200 people, they are much bigger than Scott Base, and we will work together with logistic support once construction starts.  We had a chance to meet some of the staff there, and get a better understanding of how McMurdo station functioned

What about climate change, and planning for the future?

We’re looking at a design life of 50 years for this facility and climate change is a serious consideration. For example, we have to take it into account when deciding on the depth and type of foundations in case the active layer of permafrost changes. We’ve considered seismic activity, though historically the risk is very low in this area, but if the ice cap starts to melt, that could affect local tectonic movement. Then there’s Mount Erebus not far from the base, the most active volcano in Antarctica, which is continuously active, but at a low level. Input received from a volcanologist noted it has been stable in the past, but this could change at any time!

Climate change and natural hazards are difficult to predict, and we’re on a constant learning curve. But that’s what makes this project so interesting.

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