W11 - Poetics of Etreme Context Part 2 ( TE2.3, TE 2.5, CC3.4, C 4.2, C 4.4)

What are the key design features that affect the evolution of Halley Research Station to Halley VI?

• How does the surrounding context affected the design evolution of Halley Research Station?
• How is the Hydraulic Leg Jacking System of Halley VI a context-related solution? 

1. What are the main context-related elements needed to be considered in Halley's design?

Context: The Brunt Ice Shelf

Since the mid-1950s, Halley Research Station has been placed on the Brunt Ice Shelf of Antarctica, which is a 100-m-thick floating area of ice that is fed mainly by ice flowing from Dronning Maud Land. As it moves several hundred metres a year towards the ocean, it takes Halley station with it. As a consequence, the station drifts northwest by half a kilometre each year. Once the ice shelf reaches the Weddell Sea, it is put under strain from higher temperatures and the motion of tides until parts of it eventually break off into icebergs.

An Envisat image featuring the Brunt Ice Shelf lying against the Weddell Sea on the coast of northern Coats Land in Antarctica. Source: "Photo: Brunt Ice Shelf as Seen From Orbit", Spaceref. Extracted from http://www.spaceref.com/news/viewsr.html?pid=36679

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Halley Statistics

• Temperature extremes +4° C to -55.3° C
• Annual mean -18.5° C
• Monthly mean: -28° C July (midwinter), -24° C Jan (midsummer)
• Average wind speed 13.3 knots (15.3 mph - 24.6 kph)
• Peak gust 80 knots (92 mph - 148 kph)
• Elevation 30meters above sea level, (98 feet)

Due to the fact that the temperature of the region is mostly below absolute zero, the land where Halley research station is located often experience no melting at all and so all of the snow and ice that falls accumulates continuously. The average wind speed is also fairly high and the unpredictable weather of the Antarctica is notably aggressive. This contextual element is well-known in the Antarctic Peninsula and affected most design evolution of the regional built environment.

Main context-related elements needed to be considered in Halley's design:

• the build up of snow since the snow doesn't melt
• mobility for the research station since the ice-shelf keeps moving towards the ocean

2. How does the evolution of Halley design deal with these context-related elements?

Early Solution

Halley I, II, III and IV

Base design - huts on snow surface, became buried over time due to snow build up

This accumulation of snow was anticipated when such bases were built, and in the case of the UK base at Halley Bay first built in 1956, the construction was particularly strong to take the weight of the accumulating snow and ice which had almost completely covered the original (conventional style) buildings at the end of the first year. The snowfall at Halley accumulates at the rate of around 1.5m (5ft) per year.

Original Halley station, a simple collection of wooden hut. (1956 - 1967)

New buildings that were added the following years were also buried by snow, forming a multi-level complex below the surface.

Life below "ground"

Access was by a regularly dug-out slope down to the doors until it became impossible to keep these clear. At this point access became via a hatch in the roof. As snow and ice build up continued, so the height of the access hatch increased to reach the surface.

Eventually in 1967 after 11 years this first base was abandoned due to a  difficulty of access but more importantly as the buildings were being crushed. Parts of the base were 30-40 feet under the surface level at this time.

A new station was built to replace the original complex. Halley II was also made up of a series of wooden huts, but the roofs were reinforced with steel supports to help support the weight of the snow. Unfortunately this proved no more successful than the original design and the station had to be abandoned after just seven years.

Halley II after its first winter.

Halley III was the first station specifically designed to be able to cope with being buried by the ice. The buildings were prefabricated huts surrounded by corrugated steel conduits, which helped prevent the movement of the ice from crushing the structures inside. Halley III lasted for 12 years before it was abandoned in 1983. By this stage it was becoming too deep to access safely. Also, heat escaping from the buildings increased the movement of the surrounding the ice, which crushed the steel tubing and distorted the structure of the base.

A similar design was chosen for Halley IV, though this time of insulated plywood panels time making two large tubes interconnected in a H-shape that would insulate the huts they contained better than the metal had done which gave problems of its own when snow and ice touching the tube in the warmer parts of the base caused melting. This lasted four years and then in 1989 a different approach was attempted.

Halley III - construction of the corrugated steel conduits.

The entrance shaft of Halley III after being buried by snow.

Construction of Halley IV using the interlocking plywood panels
with specially constructed air gaps to prevent heat from the station
from escaping into the ice which was the problem experienced in Halley III.

Halley IV station.

Halley V - a solution for the snow build-up

Base design - supported on jackable legs above the snow surface

Rather than a base that would be buried and inevitably lead to its destruction and waste, a base was planned that would be on the surface and stay on the surface. It would be held off the ice surface by legs which would be "jackable" that is they could be jacked up slowly by operating a mechanism similar to a car jack.

Haley V with its jackable legs above the snow surface.

In this way the base could be kept above the snow as the level grew higher beneath it, all that would be lost would be the metal legs left behind in the ice. Similar solutions had been used successfully on a smaller scale before with cabooses (essentially kitted out shipping containers) being treated this way at Halley.

It was the most successful base in that it lasted 20 years and led to less frequent disruption from re-builds. In fact it could have had a lifespan longer than this. The reason it was replaced was that as it was situated on a moving ice-shelf, it slowly moved closer to the sea and there was a danger that a large ice break-out could have  left it and it's base compliment of scientists and support staff floating on an ice berg. Worse still the station could be situated on a future break-up zone itself and suffer a disastrous loss of the base and possibly of life.