The elevated station—the largest facility ever constructed on ice—is the centerpiece of the South Pole Station Modernization (SPSM). This $153-million project infrastructure upgrade and station replacement, begun conceptually in 1994, increases the ability to support the telecommunications and technology needs of a growing research community. Laying the ground work for the SPSM, the South Pole Safety and Environmental project (SPSE) started construction in 1996. The SPSE includes a new garage facility and an upgraded power plant constructed below the surface of the ice within steel arches 44 feet in diameter, as well as a new fuel storage facility.

This first phase of the new station's occupancy comes some two and a half years after construction began on the elevated station and after almost a decade of planning. Since October 2000, when the first pieces of the new elevated station began arriving at the South Pole, the station has been in transition. Only the first two modules (A1 & A2) of the station's planned eight modules are in use this season. The focus of the work this winter season is on framing and fitting out module A3 of the elevated station, which will contain a new medical ward, stores, a high-tech food growth chamber, and a computer area. Recent improvements to the station's communication infrastructure include the addition of a satellite ground station, which expanded the data communication window from four hours a day to eleven.

The National Science Foundation, which administers all U.S. Antarctic programs, including those at the South Pole station, has outlined the following goals for the station modernization project:

• Maintain a U.S. presence in accordance with national policy;
• Provide a safe working and living environment;
• Provide a platform for science; and
• Achieve a 25-year station life.

"Government contracts like this one can take as long as 15 years to complete from start to finish," says Louis DeMaria, project manager for Raytheon Polar Services, which has provided logistical support to the U.S. Antarctic Program since 2000. (Raytheon Polar Services was awarded an O&M contract with the National Science Foundation in 2000. The predecessor company, ASA, started the construction program in 1998.) "Technologies and construction methods, as well as congressional funding, change during that long a procurement period, so we are constantly changing our long-term planning activities to reflect changes to the design or the implementation schedule."

Polar Research on the Rise

Research activity at the Amundsen-Scott South Pole Station had its humble beginnings in the International Geophysical Year (IGY) of 1957-58, an auspicious 18 month period that inaugurated a period of unprecedented scientific exploration of Antarctica. Research at the Pole has expanded steadily in the intervening years. Today the station attracts scientists from a broad range of disciplines including astronomy, astrophysics, biomedical studies, glaciology, geophysics, meteorology, seismology, and the physics of the upper atmosphere. But with this increased research activity has come a corresponding increase in the number of researchers and support staff.

In 1975, construction of a new station was completed beneath a geodesic dome 53 feet high and 165 feet in diameter, replacing the military-style outpost of tent structures and wooden buildings maintained since 1957. Detached buildings house instruments for monitoring the upper and lower atmosphere and for numerous and complex projects in astronomy and astrophysics. The station was designed to support a maximum winter population of 33 people within the dome, including scientists and support personnel. The summer population, usually between 40 and 100, would live in a "summer camp" established on the snow.

Although a marvel when first occupied, the new station was already beginning to exceed its design life and population capacity by the mid-1990s. In the 1990s, a number of science and berthing structures were added to the station. Once the station's most visible feature, the dome now sits in more than 20 feet of drifted snow and the increasing load poses a danger to the structure. Meanwhile the summer population at the Pole has surpassed 220 persons, including scientists and personnel for construction, station support, and maintenance.

A Very Challenging Project

The South Pole's location is what makes it attractive to research areas such as infrared and submillimeter astronomy, the study of seismic and atmospheric waves, and research on long-term effects of human activities on the atmosphere. Sitting atop an ice sheet at Earth's axis of rotation, the Pole has a high altitude (9,355 feet above sea level) and a cold dry atmosphere (with less than two percent average humidity). Its remoteness from centers of human population makes it one of the quietest and cleanest places on Earth.

But building at the Pole brings with it many challenges, not the least of which is the climate.

• The South Pole station sits atop an ice sheet on the polar plateau at a distance of some 850 miles from the nearest port. All materials must be flown in.

• The National Science Foundation has stipulated that research activities at the existing station be fully supported during the construction of the new station.

• The majority of all work must be completed during the austral summer from around November 1 to February 15 (approximately 110 days) when the Pole enjoys 24 hours of sunlight and relatively mild temperatures of -20°F (austral winter temperatures can dip as low as -110°F).

• The construction team operates with a fixed work force. While attrition can reduce the numbers, it is virtually impossible to increase construction staff once a summer season begins. It is definitely impossible to increase or decrease the winter staff since there are no flights to the Pole in winter.

• Because of the extreme environmental conditions at the Pole, each hour of planned construction work will take 2.16 times longer to accomplish at the South Pole than elsewhere. This productivity factor, based on 10 years of construction experience in Antarctica, takes into account factors including altitude (which can lead to altitude sickness, shortness of breath, and headaches), temperatures (which necessitates frequent breaks), clothing (which limits range of motion and dexterity), and isolation (which tends to result in fatigue and a lack of concentration).

• Strict environmental guidelines for waste disposal and waste management add another layer of complexity. The Madrid Protocol to the Antarctic Treaty (1991) designated Antarctica as a natural reserve. As a result no waste materials, human or otherwise, are allowed to remain behind and must be removed from the continent for disposal.

Infrastructure Upgrade

To support station expansion, the existing infrastructure needed to be upgraded. Carlton Walker, South Pole construction manager for Raytheon Polar Services and a 14-year veteran of South Pole construction projects, compares the process to that of building a subdivision or other new development anywhere in the world.

"You have to make sure you have the infrastructure to support the end product," says Walker. "So first you lay out your streets, make sure you have sewer, water, and so on. Once your infrastructure is in place you can start building resorts, houses, or whatever. But without utilities and infrastructure you have nothing."

The SPSE project, which began construction in 1996, upgraded the station's infrastructure.

"We knew that the garage we had couldn't keep up with the equipment maintenance related to a project of this scale, so we built a new garage. We knew that the existing power plant wouldn't carry the new station or the population required to build the new station, so we built a new power plant. Demand for power drives demand for fuel, so we doubled our fuel storage capabilities," says Walker.

The new power plant came online in January 2001, increasing power capacity and providing the station with important redundancies.

The Elevated Station

The new station sits on a platform supported by 36 steel pipe columns three feet in diameter. The columns, which are located outside the building envelope, transfer building loads to welded-steel box beams on timber raft footings.

The new station consists of two two-story, C-shaped pods with a two-story connecting link between them. Each pod is made up of four modules, lettered A through D. The two modules forming the back of the C are each 27.4 m (81 feet) wide by 14.9 m (48 feet) deep. The modules forming the legs of the C are each 11.6 m (38 feet) wide and 30.3 m (99 feet) long. A vertical tower and a surface passageway connect the elevated station to the facilities on the snow surface.

Currently modules A1, A2, A3, and B2 are enclosed. Steel is partially erected on B1 and B3 and the plan is to enclose them and install temporary heat during the next austral summer (2003-04), and then finish out the interiors over the following winter. Next summer's construction schedule also includes the installation of an emergency power generator in wing B1. Fit out of modules A4 and B4 would follow the next austral summer (2004-05).

Before starting construction, the snow pad beneath the new station was excavated and compacted to minimize overall settlement and to eliminate the inconsistent snow density in the station footprint that resulted from years of airplane and vehicle traffic. The snow pad was developed by backfilling snow and driving over it with front-end loaders. This needs to be done carefully. If the snow is worked too much the snow crystals lose their points and the snow becomes more difficult to compact.

Additionally, the building pad is built up almost six feet above the existing snow level to the bottom of the footings to give the station a head start on snow accumulation. This effectively pushes the first jacking of the station 10 years beyond the time it would have been required if the column foundations were at the existing grade.

No Square Corners

The station's profile is configured to channel prevailing winds beneath the buildings, thus avoiding potential snowdrifts. To avoid square corners, the first floor of the station is set back on the windward side, a chamfer or rounded exterior cladding (also referred to as "armadillo shells") will be added once the station is complete. A fabric wind deflector will also be added to the connecting link to mimic the shape of the front modules.

"It's a matter of allowing the wind to flow under the building as easily as possible so that we don't get snow accumulation. Right now, since we haven't installed that chamfer, the wind hits that square face, rolls back, and creates a drift on the upwind side of the station," says Walker, adding that this drift must be cleared at the beginning of each summer season.

This outer skin will not be installed until the interior of the station is fully operational. The skin is quite heavy and by delaying the installation flights can be used to transport other materials and equipment for now.

"Our priority is getting as much of the facility functional as possible since the primary role of the new station is to support research," says DeMaria. "The more of the new station that we make operational, the more support we can provide to the scientists."

Raising the Roof (and Everything Else)

Snow will continue to accumulate, however, so the design also allows for the entire station to be jacked up to maintain the necessary clearance.

In 10 years, hydraulic jacks will be used to add an extension to the top of each column. The jacks will be placed under spreader beams at the top of each extended column, connecting the spreader beam to the trusses with steel rods. The trusses are disengaged from the columns, while the station is hoisted a full floor's height (3 m), and then re-secured again at the top of the column extension.

Each pod will be lifted approximately 10 inches at a time in an alternating series until the entire station is raised about 10 feet. The process will require one operator at each column. With 18 columns per C-shaped pod, the process will require a crew of 18 operators and 36 100-ton hydraulic jacks. The entire process is estimated to take approximately 30 days.

Test Building

The SPSM team has employed the concept of "test building" to maximize on-site efficiency. For example, the jacking procedure was pre-tested in the U.S. to verify the procedure would work at the South Pole. Parts of the main structure were also pre-built in the U.S. with the help of equipment vendors. This allows the construction team to determine whether various processes will work and what needs to be changed to accommodate working when exposed to -60°F temperatures and high altitude conditions at the Pole.

For example, section B1 was pre-erected in the parking lot outside Raytheon Polar Services's offices in Colorado in order to train the erection team before going to the Pole. Antennas and most electronic systems are also pre-tested prior to shipment to confirm operability and to teach personnel what is involved in the assembly and startup processes.

"We can put a preliminary plan together but by test building we can see whether the order will actually work once we get to the Pole," says Walker. "If we can climb the learning curve here it's only going to save us there."

DeMaria points out that another reason for test building is personnel turnover.

"At the craft level, only about 40 percent of the SPSM construction team returns each year so it is paramount that new personnel have a proper indoctrination," he says.

By Lee Ingalls