Architect and Builder December 2016 | Page 79

process, is no mean feat, both from a design and a construction point of view. Underpinning of the foundations was undertaken by mining under the existing lower level suspended slabs, firstly by excavating using remote controlled Bobcats with their hoods cut off and then installing mini precast piles. Special consideration had to be given to access to the workface for the installation of most of the steelwork. The loading limitation on the rooftop carpark slab was only 2,0kPa with the maximum vehicle weight limited to 5,000kgs. The tower crane that was installed by the main contractor on the site covered only 60% of the rooftop cinema complex area and had limited load capacity at radius. A number of the internal structures were designed with plate web girders spanning in excess of 15 metres which had to be manhandled into position and hoisted by scaffold tower and chain blocks. Loads of up to 3,5 ton and lengths of over 18m had to be trolleyed through and around the cinema structure to then be hoisted to final level by building high scaffold towers over them and pulling them up with suitable capacity chain blocks - an extremely time consuming and expensive means of erection. Connection design, particularly between the numerous beams throughout the lower levels of the cinema complex and all the Steel Awards Bond-Dek slab support beams, was a major cost-saving item from a fabrication point of view. Minimal, if any, welding was employed, rather opting for bolted connections with back to back angles bolted through the incoming beam webs to achieve all end plate connection details. Due to the high visibility of the building, great care was given to the aesthetics. The building form consisted of scalloped segments with sloped Kingspan side cladding & aluminium roof sheeting. Client / Owner / Developer: Liberty Life Architect: Batley & Partners Structural Engineer: Aurecon Group Quantity Surveyor: NWS Quantity Surveyors Project Manager: Focus Project Management Main Contractor: Stefanutti Stocks Building Gauteng Steelwork Contractor and Nominator: Tass Engineering Structural Steel Detailer / Detailing Company: 3DStruct Erector: On Par Erection Works Metal Roofing and Bond-Dek Supplier: Global Roofing Solutions Bond-Dek & Shear Stud Installation: Builcon Roofing and Cladding Contractor: Chartwell Roofing 77