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Antarctica: Neumayer Station III successfully raised

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The snow and ice surface in the Antarctic grows continuously so the research station has to be raised annually. The construction concept and technology prove effective right from the beginning.

Nearly double the amount of fresh snow compared to previous Antarctic winters fell on Neumayer Station III during the polar winter of 2009. "Because of the unusually heavy snowfall the station building had to be raised three times in succession with the hydraulic system," says Dr. Eberhard Kohlberg, Logistics Coordinator at the research station of the Alfred Wegener Institute for Polar and Marine Research in the Helmholtz Association since December 2009.

To reach the planned level, the station has undergone two lifting operations since November during which it was raised a metre out of the snow in each case. The third and for this season last lifting operation is now being completed.

By means of the hydraulic system, the technicians raise the legs of the station during each operation. Then new snow is placed underneath and the steel legs are lowered again (see infobox). The process is demanding since the snow piles have to provide stable support for the tons of building load after only a short time. Normal operation continues at the same time without any restrictions. The residents of the Antarctic station merely notice a slight vibration, telling them that the hydraulic legs are currently in motion.

In future, too, the station will be raised every year in summer so that the masses of snow from the previous winter do not hinder research work. The prerequisites for this are a good weather forecast and far-sighted planning. A low wind speed is necessary to ensure that the overall structure of the building is not subjected to strong sideways pressure. "Fortunately there were enough windows of suitable weather this summer," states Dr. Hartwig Gernandt, Project Manager in the Logistics Department at Alfred Wegener Institute. "The mission was accomplished with great success. Everything was running routinely during the second and third lifting operation."

INFOBOX - Raising Neumayer-Station III

The engineers of the Alfred Wegener Institute who work at the station during the Antarctic summer are responsible for lifting the station building.

At the control centre in the so-called hydraulics container, station level U1, a specially developed software controls the hydraulic cylinders - bipods - in the 16 supports: they bear the station building weighing around 2,600 t. The complete lifting process consists of two operations:

1. During the actual lifting process all 16 bipods are extended by the lifting height of about 1.20 metres. The operation takes approx. two hours. Now the entire building is at an elevated position.

2. The foundations now have to be raised in pairs so that fresh snow can be placed underneath. The foundation plates cannot be set down so that the load is carried by the freshly filled snow, until the latter has hardened.

Under favourable weather conditions the entire process takes about 14 days and comprises the following steps:

- Lifting the building by extending all 16 bipods. Cable and pipe connections that go from the building to the ground have to be detached or loosened beforehand.

- Lifting the foundation plates in pairs using the bipod cylinders.

- The engineers fill new snow under the raised foundation plates by means of tracked vehicles with pusher blade and snow blower. Manual shovelling is necessary for the finishing touches so as to guarantee even distribution of the snow.

- The freshly filled snow now has to harden. The foundation plates are slowly and gradually lowered onto the snow piles. Initially the snow gives way under the load. This settling of the snow foundation has to be checked very carefully. Full loading can only take place when settling drops below a certain limit value, which is reached after about 24 hours. Now the crystalline structure of the snow is stable enough to absorb the heavy load.

- Once all 16 bipod supports have been underpinned in this way, the entire garage is filled with snow up to the now higher level. This marks the end of the lifting process. If necessary, the station building can now be raised once again.

The Alfred Wegener Institute conducts research in the Arctic, Antarctic and oceans of the temperate latitudes. It coordinates polar research in Germany and provides major infrastructure to the international scientific community, such as the Polarstern research icebreaker and stations in the Arctic and Antarctic. The Alfred Wegener Institute is one of the sixteen research centres of the Helmholtz Association, the largest scientific organisation in Germany.

Margarete Pauls | Quelle: Informationsdienst Wissenschaft
Weitere Informationen: www.awi.de

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