T U B U L A R S T R U C T U R E S c a t e g o r y n o m i n a t i o n s

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2 CATEGORY WINNER WINNER: TUBULAR STRUCTURES GALLERIA ROOF MELROSE ARCH The judges were amazed that this up-market shopping mall roof light had no architectural scheme drawings. But who needs architectural drawings if you have a top flight imaginative team? The Melrose Arch Offices and Shopping on the Piazza scheme was conceived as a return to a High Street shopping experience. It was with this design ethos in mind that the challenge of realising the Galleria as an open but covered street was tackled. Initial schemes for a glazed roof were deemed too mall-like and so sparked by Barnes Wallace s geodetic lattice structure which he used for the Vickers Wellington Bomber, the design team set about realising this unique glazed tubular steel canopy. The desire for a continuous seamless solution forced innovation geometrically and technically, as well as in the procurement process. The result was innovation from start to finish which included the construction methodology and a custom designed aluminium glazing system. The information flow was essentially paperless from geometry definition, analysis and right through to shop detailing and CNC laser cutting of the tubular steel members. The roof, covering some 2 400m 2 and spanning nearly 17m across, was conceived as a triangulated glazed skin supported on a diagonal square grid of tubular steel members seamlessly welded together. The final geometry allowed the roof to morph seamlessly around the corner whilst maintaining a high degree of repetition in both glass panel and tubular steel members. This repetition was key in the ability of the team to meet the stringent time and cost constraints that were a reality of the overall project. In order to reinforce the uniform design aesthetic, a uniform diameter tube size was used in varying wall thicknesses for all of the structural members apart from the support legs. The team then developed details which allowed for workshop prefabrication of large segments of the roof using welded connections, and concealed bolt fixings of the resultant pieces on site. After erection these site connections were then welded up and all the access holes were plugged. 42 Steel Construction Vol. 33 No. 5 September 2009

3 CATEGORY WINNER The roof straddles several building expansion joints and so the design provides for point supported legs and sufficient flexibility of the lattice to allow the movements to be accommodated within the structure without expansion joints. These strategies ensured that the desired welded together on site look was achieved whilst retaining the accuracy, time and cost benefit of prefabrication. The on-site erection of the structure presented its own problems. The roof was to be erected over a double volume area with no platform or surface for the erection crew to work from. The solution was a movable platform which was designed so that it could roll along the concrete roof s upstand beams as work progressed, much like a crane girder running on tracks. The structural segments were lifted from the truck by means of a tower crane to the roof of the building. Once there, they were placed in a jig to ensure that the radius on the frame was still correct. At this point the support legs and struts were added and fully welded. A high degree of construction accuracy was required as almost 90% of the glazing consists of pre-glazed units of uniform dimensions that were to be fixed in place on site. The end result was a project delivered on time within budget and to the delight of the client. Steel Construction Vol. 33 No. 5 September

4 CATEGORY WINNER JUDGES COMMENT The judges were amazed that this up-market shopping mall roof light had no architectural scheme drawings. But who needs architectural drawings if you have a top flight imaginative team? The judges thought this was a great demonstration of how tubular steelwork can perform when put to the challenge. A superb tubular scheme deserving of the Association of Steel Tube and Pipe Makers Tubular Category award. What further impressed them was that, despite challenges such as unforgiving glass panels, the curved shape of the roof, accommodating rain water etc., the team came up with an innovative roof that is not just-another-shopping-centre roof. And it looks great! project team AMDEC Property Development Architect Boogertman + Partners Architects (Pty) Ltd / DHK Architects JV Pure Consulting (Pty) Ltd Norval Wentzel Steinberg (Pty) Ltd Murray & Roberts Construction (Pty) Ltd Omni Struct Nkosi (Pty) Ltd 44 Steel Construction Vol. 33 No. 5 September 2009

5 CATEGORY NOMINATIONS Sci-Bono Discovery Centre GDE Science Education Centre t/a Sci-Bono Discovery Centre Principal Agent Plan IT Solutions Dynamix Architects ASM / MME JV WSP Structures Africa (Pty) Ltd Hamlyn Gebhardt s Group Five / Makhosi JV Khombanani Steel (Pty) Ltd Patio Warehouse Samrand Micheal Delport Properties (Pty) Ltd Architect Artech Ilifa Africa Engineers (Pty) Ltd B & L Bourekenaars NGA Construction Ferro Eleganza (Pty) Ltd 46 Steel Construction Vol. 33 No. 5 September 2009

6 CATEGORY NOMINATIONS Blue Downs Swimming Pool Roof City of Cape Town Architect and Project Manager ARG Design Bergstan South Africa LWA s (R/A Waterson & Hoosai cc) Tempani Construction (Pty) Ltd Mazor Steel (Pty) Ltd Robor Factory Office Block Robor (Pty) Ltd Architect Leon Havermann and Associates H.S. Services Project Manager Robor (Pty) Ltd Alert Group Alert Group 48 Steel Construction Vol. 33 No. 5 September 2009