The calculation and construction of a 30 meter span ice dome

In this paper we describe the calculation and construction of a 30 meter-span ice dome on an inflatable mould realized in the winter of 2014 in Finland. This ice structure was the world’s largest igloo and first building realized with fibre-reinforced ice (pykrete). The construction method of the Pykrete Dome consist of a combination of the construction method of T. Kokawa and the relatively unknown construction material pykrete. The construction method has been analysed and adjusted to the Pykrete Dome design. An oversized membrane is inflated under the geodesic rope cover. The inflatable structure is used as a mold for the Pykrete Dome. Water, Snow and pykrete is sprayed in thin layers onto the membrane with a temperature of -8°C or lower. The construction material pykrete is a fiber reinforced ice which can be 3 times as strong as regular ice. The pykrete is applied on the lower section of the Pykrete Dome where the stress in the shell structure are higher. By conducting various experiments the construction method has been analysed and improved. High quality sawdust is mixed with water and sprayed onto the membrane with a centrifugal pump and an adjustable nozzle.