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Elevated Station Design for the South Pole Redevelopment Project
at Amundsen-Scott South Pole Station
5. Halley V (75° 35’ S, 26° 22’ W)
The success of the Filchner Station’s jackable platform concept did not go unnoticed. In 1982, the same year that Filchner became operational, the British Antarctic Survey (BAS) had constructed and opened the third replacement of Halley Station (Halley IV) about 1000 kilometers from Filchner, on the Brunt Ice Shelf off of Coats Land. The site conditions on the Brunt Ice Shelf were severe. Annual snow deposition was on the order of 1.5 meters, gale force winds were common 180 days out of the year, and the annual seaward movement of the ice shelf was approximately 850 meters. From the station’s inception in 1957 with Halley I, structures were designed to withstand being buried and station life was essentially subterranean. The life expectancy of each new replacement station was only 8 to 10 years. Weary of living below the surface and hopeful of reducing the ever-increasing costs of rebuilding an entirely new station every decade, the BAS determined to change tactics and design Halley V as an elevated station based upon the jackable platform concept at Filchner.
Retaining Christiani and Nielson of Hamburg for the design, Halley V was completed and became operational in 1992. The 1,255 square meter station for 30 personnel was the most ambitious elevated facility in Antarctica at the time. It consists of three separate buildings on jackable platforms, set 300 meters apart from one another at the three points of an equilateral triangle site plan. Each platform is set initially 4 to 5 meters above the surface. The working facilities on the platforms are created from an interconnected series of prefabricated building modules. The largest facility (The Accommodation Building) is approximately 930 square meters and contains the living, working, and technical support spaces. The smaller two buildings are roughly 140 and 185 square meters, and contain laboratories. As a result of wind tunnel testing at the Cold Regions Research Engineering Laboratory (CRREL), the long axis of each building is oriented parallel to the prevailing winds in an effort to minimize any platform level drifting which would impact exterior pedestrian activity and access. Unfortunately, this orientation has had the adverse effect of aggravating drifting below the platform at the leeward end of each complex.
Halley V contends with a much greater annual snow deposition and drifting problem than either Filchner or Old Casey. As a result, jacking must be performed annually. Similar to Filchner, the platforms are lowered to the surface, the columns are extended (in this case by 2 meters), and the platforms are then raised to their restored heights and the cycle begins again. The entire jacking process takes approximately one week, and originally required one bottle jack and two operators at every column, working in unison (now the process is performed with electric jack motors). During this period the station is kept fully operational.
The steel columns supporting the jackable platforms of Halley V are stabilized by tensioned cable “X” bracing. Because of strain induced in the frame from eccentric snow creep and heave resulting from the leeward snow drifting, unanticipated problems have been encountered in maintaining column verticality. Off-vertical column inclinations of up to 200mm have had be corrected, and guying systems are now routinely utilized to maintain the columns in a vertical position, particularly prior to the annual jacking process.
After seven years of expensive and problematic station maintenance, the BAS is seriously researching the possibility of using on-grade non-jackable sled-based relocatable buildings to serve as Halley V’s eventual replacement.
The experience at Halley illustrates that an elevated station design which can work effectively in one location (such as the case for Filchner) may be less successful in another, and it reinforces the idea that successful architectural and engineering solutions must be carefully tailored to address site specific conditions.
Proceed to next section: 6. A New Vision for Amundsen-Scott Station
Table of Contents
1. Abstract
2. Background
3. Old Casey Station
4. Filchner Station
5. Halley V
6. A New Vision for Amundsen-Scott Station
7. Amundsen-Scott Station Design Features
8. Conclusion
9. References
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