Architect and Builder Magazine South Africa Dec 2017 / Jan 2018 - Page 99

TUBULAR AND ARCHITECTURAL CATEGORY WINNER Globe Bar – Time Square Casino The Globe Bar is the focal point of the new Time Square Casino in Menlyn. The project entailed the fabrication and erection of a curved plate fabricated main entrance arch with the suspended tubular round shaped Globe Bar. Steel was chosen because of the fact that complex shaped curve could not be achieved in concrete in the short space of time. Steelwork was the obvious choice to give the client the architectural shape. The structure was required to receive glass panels. The casino arch structure was fabricated using the biggest possible elements, which left the least site welded connections for erection on site. Erection of the arch legs was done using a 220 ton crane on a suspended fully propped slab while lifts were taking place. The main contractor and sub-contractor coordinated a full system of back propping and stripping to accommodate client budgets. The main arch is a composite steel and concrete structure with re-bar fitted during the fabrication process. Once erected and site welded, concrete was pumped inside the plate arch using a specially designed concrete slurry. The Globe Bar was fully constructed offsite to get the geometry 100% correct. The structure was then divided into segments and welded in the largest possible transportable units. Segments were then bolted and site welded. A sacrificial inner structure of I-beams was constructed and the external frame of the Globe was pre- assembled on the inner frame to get geometry correct and to ensure the fit of glass panels. Mobile cranes and tower cranes were used during the erection of the Globe Bar suspended off the main arch legs. The last capping of the arch could only be installed once the Globe Bar was suspended from the arch legs. Some challenges in implementing this project included keeping elements within transport sizes, within a 220 ton crane lifting radius, design of backpropping to accommodate a 220 ton crane on 3 levels of slabs, erection of the members within crane capacity and site splicing (bolting and welding at high levels). Comments Spencer Earling: ”What would we have done before we had computers? We wouldn’t have tackled this. Now, with computers, we’ve taken a hemisphere which has been fully assembled after drawing and fabrication in the works…we’ve connected it to a curved/ arched plate girder…we’ve hung it off that girder…we’ve Steel Awards hung the whole structure and suspended it on top of two plate box columns which were filled with concrete. Just think about the technology and engineering specialty that turns this into an architectural masterpiece. “ Client: Sun International Architect: LYT Architects Structural Engineer: WSP Quantity Surveyor: MLC Main Contractor: WBHO Steelwork Contractor: Cadcon Structural Steel Detailer: DN Design, Beker Steel Steel Erector: On Par Cladding Contractor: Façade Solutions Corrosion Protection/Paintwork: Dram Trading 99