A workers accommodation project, which used the light steel frame building (LSFB) method on Saint Helena island, in the South Atlantic Ocean, about 1 770 km west of Luanda, Angola, and the new office building of banking firm Standard Bank in Rosebank, Johannesburg, are among the 50 entries for this year’s Southern African Institute of Steel Construction (Saisc) Steel Awards.
“The quality of this year’s entries has not disappointed. They demonstrate creativity and innovation in the use of steel and these two projects are fine examples of this,” Saisc education director Spencer Erling tells Engineering News.
The Steel Awards is the premier award show for the South African steel construction industry and it has become one of the most prestigious and respected function in South African industry.
“Any steel construction project, from houses, public buildings and bridges to industrial structures, such as warehouses and stadiums, could have been entered,” he explains, adding that selection criteria depend on many factors, including, among others, the innovative and creative use of steel, the value added to communities and the overall challenges of undertaking the projects.
Standard Bank’s new building in Oxford road is only a few hundred metres from Gautrain’s Rosebank station, making it one of the most desirable corporate addresses in Johannesburg, Erling says.
The development consists of two office towers of nine and 11 storeys respectively, each atop a multilevel underground car park. The towers are joined by a 36-m-wide and nine-storey-high atrium, which runs from north to south, enclosing multilevel escalators and link bridges at the southern end.
The east- and west-facing façades of the office towers have narrower atria, stretching from podiums at first-floor level to the roof level, allowing a substantial amount of natural light into the inner-office floor spaces.
Innovative Steel Use
The project team explains that steel was the only solution for the structure of the atrium roofs and glass-clad façades because of the large spans involved and the minimal supporting structure that the client wanted in the vertical façades.
The project’s architect, GLH Architects, worked with structural and façade engi- neer Pure Consulting, while the main contractors for the project were construction company Wilson Bayly Holmes Ovcon (WBHO) and steelwork contractor Tass Engineering.
“All three atria are of similar steel construc- tion, with saw-toothed roof trusses that encompass vertical, glass-clad faces to let in light throughout the day, as well as exposed tubular horizontal trusses carrying the double-glazed vertical façades,” explains Tass Engineering construction director Rob Mylroie.
Further, he says the western, eastern and southern atrium façades are supported at ground level by square tubular struts that continue up the complete height of the façade through each of the horizontal wind girders, providing vertical support to each of the horizontal wind girders as they pass through the façade.
Mylroie adds that the major challenge, from an engineering and fabrication point of view, was to achieve structurally sound connections, with clean smooth lines and unexposed connection bolts, throughout the exposed tubular members.
“This had particular relevance when installing the two main support girders on the northern façade and step-down roof, owing to the extremely high forces that are carried by these girders.”
The project was designed to achieve a four-star rating under the Green Building Council of South Africa’s rating system in the Design and As-Built categories.
Standard Bank has, subsequently, been awarded a five-star Design rating by the Green Building Council of South Africa and is still on track to achieve the four-star rating in terms of the final As-Built certification.
Meanwhile, Saint Helena is one of the most isolated islands in the world and its new international airport project represents a milestone for the island and South African construction company Basil Read. The company was recently awarded the contract to design, build, operate and transfer the airport.
Basil Read appointed George-based steel structures manufacturer SA Steelframe Systems to construct a village on the island for the workforce of 200 to 300 people who will build the airport, which should be operational by 2016.
The village includes accommodation, ablution and recreational units, laundries, a gymnasium and security offices, as well as kitchen and dining room units.
SA Steelframe Systems explains that LSFB offered the best solution for creating this village on the remote, environmentally sensitive island.
“When you consider the combination of reduced time of construction, the lower logistical costs of the modular system, the relative ease of assembly and, of course, the substantially smaller carbon footprint, compared with more traditional building methods, it made a lot of sense,” says SA Steelframe Systems owner Johan Marais.
He explains that the isolated nature of the island presented the team with its own challenges.
“Limited building material is available on the island, therefore, all materials had to be shipped by means of 6.1 m containers from either Cape Town, in the Western Cape, or from Walvis Bay, in Namibia,” adds Marais.
He says all the building materials, with the exception of the rockcote-coloured renders and paint system, were sourced from South Africa and delivered to Cape Town or Walvis Bay for shipping.
“An aspect of this year’s theme is proudly South African and the Saint Helena airport project shows the power of local ingenuity on a truly international stage,” notes Erling.
He adds that the work on this project is evidence of the ongoing quality and innovation in local structural steel design and construction.
As the team’s submission explained, the scope had an innovative developmental element in the sense that the accommodation units had to be converted into two- and three-bedroom houses after completion of the airport project.
Erling states that this conversion will be possible through minimal internal changes and by adjusting a few windows and doors. The houses will then be sold to local residents, he adds.
The local authorities have been so impressed by the worker’s village that they have approached SA Steelframe Systems to supply a quote for the construction of a child-care centre, an extension to a hospital and other housing needs on the island.
“The cost savings and speed of erection, coupled with the drive to create thermally efficient and environment-friendly buildings, have alerted the islanders to the availability of alternative building technologies, such as LSFB,” the submission explained.
The main sponsor of Steel Awards 2013, which will be held simultaneously in Johannesburg, Cape Town and Durban on September 19, is steel distributor Aveng Trident Steel.
Other sponsors include steel merchant Macsteel Service Centres South Africa (Table Décor); regional reseller of Tekla Structures Cadex SA (Photo Competition); The Association of Steel Tube and Pipe Manufacturers of South Africa (Tubular Award) and steel and engineering products supplier Stewarts & Lloyds (Light Steel Frame Award).
Partner sponsors include steel producer ArcelorMittal South Africa; structural engineering company B&T Steel; sole distributor of JLG access platforms and telescopic material handlers servicing Southern Africa Eazi Sales and Service; diversified engineering company Genrec Engineering; supplier of steel products and services NJR Steel; steel fabrications technologies supplier Peddinghaus South Africa; construction solutions company Tubular Holdings and diversified engineering company Vital Engineering & Angus McLeod.