Construction World November 2016

PROJECTS AND CONTRACTS

OUTSTANDING STEEL APPLICATI The project profile in this issue is Eastgate Phase II redevelopment which was the overall winner for the 2016 Steel Awards.

drum at ground level (where the building’s utilities are concealed behind a slatted timber screen). All shapes cut from the weathering steel plate had to fit into the laser cutter’s maximum size restriction, as well as the allowance for shapes that can be folded. All components of the steel structure needed to be transported to a site with narrow driveways. The house is situated high on a slope without any direct vehicular or crane access. Components were pulled to the site on a sleigh with a winch, and then hoisted up by means of a gantry supported by scaffolding surrounding the house site. Getting to a building inaccessible by road proved challenging. Some of the larger components were winched up an embankment to the position of the construction site. The site was enclosed in a scaffold structure that was covered with a tarpaulin and hail netting so that work could take place during the rainy season. Chain blocks were attached to two I-beams at the top of the scaffold structure to raise and lower compo- nents into position. The slender nature of the vertical steel structural elements meant that there was flex in the structure when loaded and the steel structure had to be braced prior to the timber being installed. What makes this project special is the high level of customisation and detail required, with very small manufacturing and assembly tolerances. Steel was used to express the natural structural systems of the trees surrounding the house. Global roofing solutions metal cladding winner New Office for Statistics South Africa Over and above its aesthetic appeal is the innovative use of metal side cladding on a commercial building, which is most unusual these days. It’s also unusual and interesting because on this state of the art modern building, we have a profile used that dates back to the 1960s. Another thing that impressed me was the incredible quality of the workmanship. In this type of an application you really have to pay attention to the detail, or the cladding will look very tacky very quickly. The Stats SA project consists of new offices and an archive building. Roof and side cladding is 0,58 mm thick galvanized Z200 GRS Brownbuilt 406 profiled sheeting with standard Chromadek finish one side and standard backing coat to other side. Sheeting colours include Dove Grey, Dark Dolphin and Charcoal. Insulation used over purlin on roof and sides were 40 mm thick white faced Lambdaboard and Sisalation 405. The site was extremely congested and installation programme dura- tion very short. The buildings were high, with lots of angles and direction changes on sides. Underslung sheeting in long lengths in Brownbuilt 406 profile tapered with angles. The Architect requested concealed-fix flashings. In order to address these challenges, the main contractor assisted with cranage and special scaffolding. Another solution included the design of special clip-on flashings. All roof sheeting, side cladding and soffit sheeting is concealed-fix sheeting. Majority of flashings was concealed-fix or designed to hide fasteners. The most impressive technical aspect of this project is the underslung Brownbuilt 406 profiled sheeting and special flashings.

We also feature the two projects that were joint winners for LSFB in the same awards in the ‘environment and sustainability category’ as LSFB has various green properties. Here we feature the remaining category winners in the 35 th annual steel awards.

Residential category winner The Tree House Constantia

Winner of the Residential Architectural Category, The Constantia Tree House is a custom designed residence that embodies both simplicity and luxury. Getting all steel components to a sloped site without direct vehicle or crane access meant using both a sleigh and then chain blocks attached to two I-beams on the top of the scaffolding. One enters the floating building by means of a weathering steel bridge with a timber deck walkway. The lowest floor contains a living area and kitchen, with two double volumes and a circular stair linking the living area visually and physically to the bedroom level above. Large sliding doors, 6 m high, open up the living level to a balcony overlooking the estate’s gardens A circular stair, with sculptural treads carved from solid standing laminated oak, and supported on weathering steel steel reaches, lead up to the bedroom level (with bathroom), and then further up to a roof deck with views over the Constantia Valley. The structural system was executed in laser-cut weathering steel plate, bent to form facetted columns, branch-like arms and rings. There are four structural column clusters, each consisting of four weathering steel columns held together with the arms and rings, to support spruce and western red cedar floor beams. The columns are bolt fixed by means of a large circular baseplate on conical concrete pad footings. There is no steel connection between any of the steel structural columns but the timber floor plate construction. The stair ‘drum’ consists of a half circular lattice framework of mild steel hollow tubing and angles – bracing the structure as it is bolted down onto a concrete

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CONSTRUCTION WORLD NOVEMBER 2016