Establishing and maintaining a long-term station on an ice sheet raises unique challenges for engineering and construction and with over a mile of ice beneath us it’s a constant battle to keep surface structures unburied. The South Pole faces similar issues, but the issue there is primarily drifting, thus the aerodynamic shape. At Summit it’s not only drifting, but also the issue of roughly a meter of snow accumulation annually. To deal with this issue there are several ideas in use: some buildings are on skis and can be dragged around the station with heavy equipment, others are modular and can be moved every few years to a berm which will gradually be buried, a few instruments are buried in vaults, and many are seasonal – simply taken down and put on a berm for winter to be set up come summer.
The Big House and TAWO however, utilize an “infinite leg” system. The buildings are raised up on stilts, or legs, and can slide up as the snow level, or grade, rises. Once they reach the top of the legs another section can be welded on and the process continues. Let me say at this point that this is not quite as easy as it sounds…but it does work and it’s pretty awesome!
The Big House is essentially a double wide trailer with the kitchen, a large refrigerator, a scullery, a bathroom with a shower and a toilet stall, the manager’s office and comms, and large common space that’s used as a dining and living room. There are lots of windows and it’s quite homey. Beneath the building, in the area scoured clear by the wind moving under the structure, there is a wide metal hatch leading down to the freezer trench where all dry and frozen food is stored. With the accumulation rate at about a meter a year, the Big House is raised every two years. During my first year up here (2010) they welded on new leg extensions and raised the building. They raised it again in 2012 and now again in 2014. The hollow, square, steel legs have holes drilled through them every ~6inches. The building rests on a set of 3/4in steel bolts that run through the holes on each leg. Small platforms are bolted to the legs below the building. When it’s time to raise the building hydraulic jacks are securely bolted to each of the smaller platforms. The jacks are connected to a manifold which regulates the hydraulic pressure across all the jacks – the system has a lifting capacity of about 120,000lbs. The jacks lift the building just enough to take the weight and then the upper bolts (or pins) can be manually removed. Once those are all removed the building is resting on the jacks and the lower platforms. It can then be raised to the next set of holes where the pins are replaced, slowly inching its way up 4-6 feet. TAWO is designed in much the same way, but a bit smaller in scale.
Here are some photos from 2010 and 2014:
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