Engineering in Antarctica | Part two

Minus 50°C, 80mph winds and 100 days of darkness. “If something goes wrong you can’t exactly pop out the door and do a quick fix.”

Ramboll structural engineering director Ben Rowe was appointed as a technical advisor for the relocation of Halley VI Research Station in Antarctica. He has been keeping a diary of his time at the site. (For part one of this series click here.)

Halley VI is a £26M modular structure jacked up on hydraulic legs, which keep it above accumulated snow. Giant retractable skis on the bottom of the legs allow the building to be towed.

Located on the Brunt Ice Shelf, the structure had to be moved due to a developing crack in the ice on which it was standing that could have eventually cut the research station off from the rest of the ice shelf.

Rowe was among a 100 strong team but was the only structural engineer – a heady task that put him in charge of checking the structure, while engineering the road and route.

13th Jan

Rowe left the UK on 26 November 2016 to work during the southern hemisphere’s summer. Following his return in February, he spoke with New Civil Engineer and shared some of his diary entries from the trip.

Managing the cold

With about 30 years’ experience as a consultant, Rowe has seen the bad the good and the ugly of project management and he says clients British Antarctic Survey had an “impressive” methodology amid the constantly changing conditions.

“The biggest issue is the snow and ice changes completely – you learn a lot about the different impacts it can have on materials, settlement,” says Rowe.

“There were times when we were moving the module, the snow was a bit slushy, which makes it harder to move because there’s more friction. If that freezes overnight, you’re dealing with ice. Then at the other end of the scale, the snow might be more powdery and you can pack it quite well.

“But you come back after a couple of sunny days, it’s softened everything, the ski sinks down into the snow, you get a full bearing surface, and it’s totally different. So you have to allow for the snow to compact, but also for the skis melting down into the ice.”

9th Jan

The modules’ legs and attached skis can be raised and lowered on hydraulic jacks. Each module weighs up to 250t. Moving such a structure that was designed to be towed sounds simple enough. But Rowe says there were definite risks at play.

“If you pull it in the wrong way or strain it, you could break the legs,” he says.

“And if it was one of the critical [energy] units, E1 or E2, you would be down to one energy module, and you could get down to the point where the building was not habitable.”

The 23km route, although pre-smoothed out, was far from pristine.

14th Jan n2

The red module, Module A, is the heaviest of all modules and was the hardest to pull. “As we were taking that one down the prepared ice and snow road, you got some very heavy bumps as you were going along, and just showed you everything was working really hard.”

Heavy vehicles hauling bulky modules makes for a great photograph, but Rowe says it was the start and finish of the operation that was most technically challenging. “It was aligning them at the end and shifting them sideways and pulling them on to each other that was the difficult part. Because you have to use a connector piece, a trelleborg unit, and it has something like 20 fixings which need to be lined up perfectly.”

All while dealing with the infamous Antarctic weather. But Rowe says his first few days there were surprisingly mild.

“If there’s no wind and the sun is out it’s actually quite pleasant. You’re there with a t-shirt, fleece and a light jacket on top. It’s not what I imagined Antarctica to be. But as soon as you lose the sun or the wind hits, it turns bitterly cold.”

17th Dec vehicles ready to rock n roll PBU1618 Courtesy of British Antarctic Survey

The goal of the operation was to avoid the crack in the ice advancing towards the Halley station. But since October 2016, the crack has grown massively, progressing about 1km every two days. Its movement is unpredictable and may run on through the new site where Halley has been transported.

“The crack’s movement is a natural phenomenon,” explains Rowe. “You’ve got a continent which is rock, then you’ve got anywhere from 200m to kilometres of snow and ice on top. As that works its way off the rock, it extrudes outwards, out into the sea to float.

“But as it goes over rocky outcrops, in particular one outcrop called McDonald Ice Rumples, it forms a rip in the bottom of it and propagates the crack.”

Halley is situated on the Brunt Ice Shelf, which appears to be solid land to the naked eye but is actually broken up and with multiple layers.

8th Jan Weddell Seal

“The icebergs are effectively glued together by sea ice and the snow that falls. So every year you get 1.5m of snow accumulation, so you can have all these types of icebergs hundreds of metres deep. So it’s already completely all broken up, you just can’t see it. So I guess that’s why the cracks can easily open up, and why, when they do, they move as quickly as they do.”

Because of the unpredictable conditions, staff are not staying at Halley during the winter, where the temperature can reach -50ºC, with 120km/h winds and 100 days of darkness. “So if something goes wrong you can’t exactly pop out the door and do a quick fix,” says Rowe.

Everyday life on a research station

Rowe kept a journal throughout his months-long journey, detailing his technical work, weather conditions, leisure time and unique observations from the continent. New Civil Engineer took a sample of entries from the diary that captures the lighter side of life in the extreme south.

Sunday 11 December

This signpost outside the front of the modules is a stark reminder of just how far I am from the UK – 14,255 kilometres to London.

14255 kilometres to London

Monday 12 December

Today I feel like I have arrived in Antarctica. Snow is being blown horizontally on the back of the 48km/h wind. Over-night this has changed the fairly flat site around the temporary camp and associated buildings to ridges and troughs everywhere. A step forward and you can immediately trip or if still upright, find your-self waist high in powdery snow.

Sunday 18 December

Awoke feeling bit rough from cold and now cough, seems that I have eventually succumbed to the Antarctic germs that everyone else has had previously.

Tuesday 27 December

This evening, we had drinks and socialised amid music in preparation for two day Fakemus, as in Fake Christmas. The Halley team has developed into a pretty tight unit, remarkable really given that we have at most known each other for five to eight weeks and will probably not see many again after the next six weeks.

23rd Dec. Jan running ground radar alongside space radar PBU3153 Image Courtesy of BAS

Wednesday 28 December

Today is our Fakemas day and very much like a normal Sunday day off with late brunch at midday. In the afternoon we organised ourselves into teams and judges for the “Halley Winter Olympics” which included tug of war, sledging, flag pole throwing, with the winning team getting the timber cup made by one of the carpenters.

Thursday 29 December

Today is Foxing Day and most are up late the morning after the night before. I went skidooing with a couple of the team and afterwards played footy in the sunshine, which, given the variable snow surface, was far more exhausting than on grass or astro. It was also a good day as we saw three Adelie penguins walk and belly slide through the site. Really cute and full of character, and not that bothered by our presence.

Saturday 31 December

In the evening we held the annual summer BBQ outside and to bring in the New Year. An ice bar was created with shots chilled in the ice. Pretty nippy in the evening so most of us eventually migrated inside once we had eaten. The key was to eat very quickly before the food had gone cold or re-frozen.

6th Jan Adelie Penguin

Sunday 8 January

I finally got my name onto the list for the Sunday trip and went to Creek 3.

There were 11 of us doing the trip. After grabbing some water and a sandwich for lunch I jumped into a sledge with transit bag.

I went to the WASP (winter accommodation building for the science team) building to pick some climbing boots and then jumped into the Snowcat for the trip. The Snowcat is a really cool and quirky looking vehicle – almost like a Land Rover on high suspension and triangular tracks.

The Snowcat carried nine of us and the other four rode in the sledge dragged behind. Just before we arrived at the creek we got a radio call from the people in the sledge saying the rope had broken free. We looked out the back window to see them deserted and at a standstill 100m behind. Our field guide turned round to pick them back up and found that a small burr on the shackle had, over the distance of travel, cut through the rope.

21st Jan Bridge second dropper fixed whilst supported from crane above

The other field guides had gone on ahead on skidoos to set up climbing ropes over an ice cliff and to check out the safety of the sea ice shelf.

When we arrived we popped on crampons and harness in preparation for the climb. We were shown how to use ice picks and crampons and then let loose on the various climb routes under the watch of the field guides.

We then walked onto the sea ice carefully stepping over the crack with the ice shelf.

4th Jan 3

Tuesday 17 January

We got the B1 module line and levelled. We then travelled back to site 6 to move the final B2 module. We took the normal rigging team and to celebrate moving the last module they joined myself and Oli inside for the re-location journey. Spirits were high so we popped on comedy wigs from the dressing up box stored in the module, and waved goodbye to site 6 from the rear fire escape.

We brought along some snacks and played music and chatted the entire 4 or so hours.

When we arrived at the other end there was lots of whooping, as the chief engineer counted in the last module. We all made it down the fire escape ladder and wandered over to the temporary camp to continue celebrating the re-location success. The team were in high spirits, we eventually turned in around 4am.

24th Dec Ben Ramboll and Jan RADAR guru looking at breakthrough on mast movement understanding Image BAS

Thursday 19 January

I was just about up and ready for the 8am start. The over-night moves, six day weeks, eleven hour days and communal living do play a toll on your energy levels – however others seem to be suffering more than me.

First thing this morning I did the full level survey of all the module legs, soffits and skis. Standing in front of the dumpy level doing very precise movements to sight the instrument and record the information meant my fingers were freezing within 30 minutes. Halfway through I stopped to get my circulation moving and found this was initially more painful than the cold.

Monday 23 January

I undertook a new survey this morning to understand the settlement in the snow packed foundations and re-check how much we need to adjust to get to our target level.

I was surprised that this suggested that even skis in place for a fortnight had settled 70mm in four days, and the latest module moved just about a week ago has settled by 100mm. This is massive and makes you understand that as long and everything remains relative that this sort of movement is not that important.

Halley at dusk2 Credit. British Antarctic Survey

Tuesday 24 January

Saturday is karaoke night and Sunday is the organised trip under your own power from site 6 to 6a. Some are skiing, cycling, walking, running. However more recently there is an option to test drive some of the vehicles used out here – this sounds more fun as an experience so probably will get involved in this.

Thursday 26 January

We had few drinks in the temporary camp and at around 10pm went to take what could have been my last photos and video of the modules. When I arrived in module A, the team had been looking for me as they were having a bit of a party. It feels now like the end has come about very quickly – but I understand that this is quite usual towards the end of a season.