The swimming track "transforms" into a curling track - how to switch freely between "water cube" and "ice cube"

Xinhua News Agency, Beijing, February 1 -- The Winter Olympics you don't know: the swimming lane "transformed" into a curling lane

- How to switch between "Water Cube" and "Ice Cube" freely

Xinhua News Agency reporter Ma Sijia Liang Jinxiong

On February 2, the first game of the Beijing Winter Olympics, the curling competition, will be held at the National Aquatics Center "Ice Cube", where the sparkling blue lanes of the former "Water Cube" will be transformed into four crystal clear curling lanes, welcoming 30 teams from 14 countries.

The "Water Cube" is the world's first Olympic venue to complete the "water ice conversion". At the 2008 Beijing Olympics, the Water Cube produced 42 swimming gold medals. This year, the Summer Olympic heritage incarnated as the "Ice Cube" to serve the Winter Olympics, which will produce three gold medals in curling men's, women's quads and mixed doubles.

Achieving the free switching of "ice" and "water" and making full use of the venue all year round are the biggest challenges. To this end, the National Aquatics Center and Harbin Institute of Technology and other scientific research teams, in accordance with the "water ice conversion, two-wheel drive" strategy, to carry out structure, temperature, humidity, lighting, acoustics and other aspects of the key transformation, put forward an unprecedented concept - to erect a detachable ice rink above the pool.

First, the staff needed to drain the water from the pool and build a convertible support structure with steel frames at the bottom, that is, 2680 steel frames. Curling projects have very high requirements on the ice surface, even a millimeter height difference can have an impact, so the engineers designed an adjustment bolt under each steel pipe, which can be adjusted by turning the bolt to adjust the height of the steel frame.

Once the steel frame foundation is set, concrete precast panels are laid – engineers have specially customized dimensions that are easy to disassemble and assemble, and the height difference is measured by laser trackers to ensure flatness. The prefabricated board platform should also be laid with waterproof layer, insulation layer, moisture-proof layer, etc., as well as ice-making pipes. These ice pipes need to be reused in the future, so engineers number each pipe and the corresponding interface to quickly and accurately install it back in place during the next Ice Water Conversion.

Next up is the ice making session. The outdoor integrated skid-stop ice-making unit is like a container, and can be moved to any place for ice-making work as a whole. The refrigerant is transported from the outdoors through pre-laid lines to the base ice pipes, which are carefully sprinkled several times to form the ice surface of the track. Ice-making water is pre-treated and highly filtered water.

After the "Ice Water Conversion" system is completed, it only takes twenty days for the "Water Cube" to become an "Ice Cube" through rapid assembly and construction.

Engineers have also established a "health monitoring" system for the curling arena, including acceleration sensors, strain sensors, ambient temperature sensors, etc., which can not only monitor the deformation and vibration of the structure, but also monitor the ambient temperature and the overall structural inclination, and evaluate the safety of the structure and the comfort of the competition in real time.

Three different temperatures must also be ensured in the curling arena – the track needs to be kept at minus 8.5 degrees Celsius at all times; the 1.5 meters above the ice surface is controlled at about 10 degrees Celsius; and the temperature in the grandstand area is between 16 and 18 degrees Celsius, and the hot air blows from the air outlet under the seats to ensure that the spectators can watch the game comfortably.

Whether it's the "Water Cube" or the "Ice Cube," "Green" is their unfading label. The "Water Cube" translucent roof has good light transmission and can take full advantage of natural light changes to meet the temperature requirements of the pool in the venue, but it is not friendly to the ice surface.

The engineering team finally decided to put on a "sunscreen suit" for the Ice Cube. In order to find the right material, the team repeatedly simulated the test, and finally selected a membrane material with a thickness of about 0.26 mm, which was covered on each bubble of the "Water Cube", effectively turning the high temperature and high humidity environment of the swimming pool into the low temperature and low humidity environment required for the curling field, and reducing the load of thermal radiation on the operation of the ice making system.

After the End of the Winter Olympics and The Winter Paralympic Games, the "Ice Cube" will also become a comprehensive ice project platform integrating the functions of holding high-quality ice events, public ice fitness, curling sports promotion, etc., so that the "Double Olympic" heritage will continue to shine. (End)

A staff member prepares in the "Ice Cube"