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2017WinterShotcreteEMag

Fig. 3: Street view of Timaru cement storage dome. Aesthetics were a major consideration when deciding on a storage solution. The dome durability, white fabric color, insulation, price, and Domtec’s reputation also figured into the contract award tion and isolation properties, a benefit during construction and operation of the dome. • Dome silos can be fitted with a complete reclaim floor, guaranteeing 98% extraction rates. • The dome shape provides a high volume of storage within a relatively small footprint. • This port had height and space constraints. The dome could achieve the tonnage required within a footprint and height that would work. • The dome shape is inherently strong because of the seamless blending of the wall and roof. This provides excellent structural integrity, resistance to earthquakes, and severe weather conditions. This inherent strength also allows the cement to be placed high against the walls and roof. • The technique of using shotcrete allows efficient and economical construction (eliminating the need for formwork, shoring, and waste). It also enables rapid construction of the domes regardless of weather conditions because after the inflatable form is erected, all works are performed inside the dome. • Domes are ideal for combining with pneumatic extraction equipment from ships, to dome, to truck loading, and can accommodate high-volume filling and discharge rates. • The dome supports heavy loads on the apex and asymmetrical loading against the walls, allowing side discharge and avoiding sub-grade reclaim tunnels. Each of the Holcim domes were designed to support 150,000 lb (68,000 kg) without any interior bracing or exterior bents. • Building authorities had no experience with dome construction, but the lead contractor, together with Domtec International, put together a presentation that answered all questions and alleviated all risk and safety concerns (Williams and Cowie 2016). DOME DESIGN The dome storage building went through a strict peer review process that involved structural engineers in five countries on three continents. The dome was engineered using ACI, New Zealand/Australia, and Eurocode standards Fig. 4: View of dome apex from inside of dome. When completed, each apex was designed to support 150,000 lb (approximately 62 tons 68 tonnes) without any interior supports Fig. 5: Finished interior wall of dome. The dome used roughly 1923 yd3 (1470 m3) of shotcrete www.shotcrete.org Winter 2017 | Shotcrete 27


2017WinterShotcreteEMag
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