Freedomes provide the most efficient shape for a stockpile
enclosure because they are lightweight and can span large areas
without intermediate supports. The most common dome shape
is a segment of a sphere, but it is more economical to use
varying radii of curvature for the meridian of the dome. The goal
is to have the dome ‘hug’ the clearance line of the stacker-
reclaimer. This results in a smaller dome surface area and better clearance for vehicles around the perimeter. With this in mind,
Geometrica designed and installed a circular dome for Kampot
Cement spanning 86m that now helps facilitate the production
capacity of 950,000 tonnes of cement per year.
Lucky Cement: Lucky Cement Corporation in Taipei, Taiwan
manufactures and sells Portland, ground granulated blast-furnace
slag, fly ash, and blast-furnace slag cement. The company needed
two domes to cover its bulk materials. One required a highly
irregular design to accommodate a sprawling stockpile, while the
other required a long span of 104m to cover more than 35,000
tonnes. Both domes were built while the stockpile was in
operation — no downtime.
After carefully considering the fluctuations of the natural-gas
market in recent years, PT Pupuk Kalimantan Timur (Pupuk-
Kaltim), Indonesia’s largest fertilizer producer, in Bontang, East
Kalimantan, launched a project to diversify its fuel with a coal
boiler in 2009. In addition to adhering to government policies
that encourage the use of coal as a substitute for natural gas,
Pupuk-Kaltim executives noted substantial economic benefits.
Geometrica was selected to design and construct a coal storage dome for Pupuk-Kaltim based on the ability to meet very specific logistical and environmental needs.
Any visitor to Kaohsiung Hsien will notice four massive solid fuel silos. When Taiwan’s state-owned Energy Company,Tai Power, decided to expand and cover its raw material stockpiles, it relied on Geometrica’s design expertise. The challenge was to design silos that could resist corrosive saltwater spray and typhoon winds. Gibsin Engineers LTD, a specialist company hired by TaiPower, determined that four long span concrete silos with metal dome covers would be required.
Geometrica designed and installed the domes with a ‘perimeter-in’ method of construction: the first nodes and tubes were laid on the supporting concrete wall. Each three to five tubes were joined to one node forming a ‘spider’. Each spider was then raised to the work front and tapped into place, creating rings around the base that grew one on top of the other until the whole skeleton was formed. Co-ordination with other suppliers was easy, as the area under the dome was free of obstacles. Neither scaffolding nor other special equipment were required, and the project was completed with a perfect safety record.
Freedomes are built of lightweight and strong galvanized steel or aluminium, comprised of prefabricated tubes using Geometrica’s computer-based manufacturing system. The tubes are bar-coded, packaged and shipped to the job site. They are connected on site with patented aluminium hubs comprised of an extruded aluminium cylinder with several threaded slots. Each tube is flattened at the ends into a pattern that slides into a hub’s slot. The connection of tubes and hub is compact, simple and very efficient — no welding required. When all tubes for a hub have been assembled, the joint is finished with washers and a single bolt. When completed, Geometrica’s patented hub connection is stronger than the tubes themselves.