Home Upfront Now Up Books Towns Structures People Firms Lexicon		Architrix : GRC elephant foot : The Palace, the Lost City, Sun City _____________________________________________________ Author: Wegelin, Hans In: SA Architect Vol 22, Issue 5, May Date: 1992 Pages: 43 _____________________________________________________
GRC ELEPHANT FOOT Palace Hotel, Lost City 1992 The scale and artistry of precast work on the Lost City project at Sun City is unique in the world. Four types of precasting were used, namely glass fibre reinforced concrete (GRC), glass fibre reinforced plastics (GRP), precast concrete, and polypropylene stainless steel fibre reinforced concrete. Together they account for about 25 000 pieces with a value of R35 million. Contract time limits dictated that the precast work be spread amongst 10 manufacturing companies. The art work for the precasting was done locally by 14 artists under the supervision of Americans with experience in the building of Hollywood sets. They prepared models from high-density foam plastic from which a rubber mould is made. A GRP master model was cast from this mould and kept for future use in case something should happen to the mould in use. GRC, being an ideal combination of brittle and tensile materials—cement, sand and glass, which produce a tough composite—makes it possible to produce thinner and lighter units than steel reinforced concrete, which requires a certain cover of the reinforcement. The glass fibre used is Pilkington's Cemfill 2, which has improved alkaline resistance. Casting and testing was done on site. All GRC panels are single skin and kept to below 6 m in length. They are fixed to galvanised steel stud frames with gravity anchors (to carry the dead load) and flex anchors (to allow for thermal or moisture movement of the skin). The frames are spaced at about 600 mm and provided with toes which are fixed to the GRC skin with GRC bonding pads. The stud frames in turn are fixed to the main building structure by bolting or welding, allowing for adjustment. Joints between panels or walls are filled with polysulphide in colours made up to match the panel finish. The panels are "aged" by means of painting sprayed down with water to achieve the desired effect—the building is supposed to look 2 000 years old! Architect: Wimberly Allison Tong & Goo, California, USA. Supervising architect: Burg Doherty Bryant & Associates Consulting Engineers: Lines, Smolka & Associate Specialist Consultant in Precasting: Mario Lupini
Buildings linked to this article Lost City - The Palace, 1992, Sun City, North West. pp 43