Following the announcement of the Steel Awards winners for 2016, WALLS & ROOFS takes a closer look at the winning projects.
The 35th annual Steel Awards, hosted by the Southern African Institute of Steel Construction (SAISC) in partnership with BSi Steel, once again showcased projects that exemplify excellence in the use of structural steel.
Paolo Trinchero, chief executive officer of SAISC, noted that the broad range of entries was encouraging and a number of projects this year displayed characteristics of a winning industry. “They showed innovation in every process and the integration of design, detailing, fabrication and erection using modern CNC equipment and software which our industry has invested in so heavily,” he commented.
Here are the winners:
Commercial architectural category and overall winner
The Eastgate Phase 2 Redevelopment
As part of a major facelift at Eastgate Mall, the lower-level cinema complex was relocated onto a section of the roof-level car park, enabling more retail space at the lower level as well as within the new cinema complex at roof level, all while keeping the entire shopping centre operational.
Steelwork was chosen as the main structural component to support the major 5 000m² structure on a suspended concrete carpark slab over two levels of retail space. 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 the workface since the loading limitation on the rooftop carpark slab was only 2kPa and the maximum vehicle weight limited to 5 000kg. 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 15m, which had to be man-handled into position and hoisted by scaffold tower and chain blocks.
Loads of up to 3,5t and lengths of over 18m had to be trolleyed or man-handled through and around the cinema structure to then be hoisted to the 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 the 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.
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 and aluminium roof sheeting.
“I’ve sent students there. I’ve seen the drawings. I just think that what they’ve achieved in a working shopping centre, that’s absolutely changed the mall totally, is really a fantastic piece of engineering work.” – Spencer Erling, retired SAISC director and seasoned Steel Awards judge convener.
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 (Pty) Ltd
Structural steel detailer/detailing company: 3DStruct
Erector: On Par Erection Works
Metal roofing and bond-dek supplier: Global Roofing Solutions
Bond-dek and shear stud installation: Builcon
Roofing and cladding contractor: Chartwell Roofing
ASPTM Tubular category
Seisa Ramabodu Stadium
Home to Bloemfontein Celtic, the Seisa Ramabodu Stadium was renovated to better serve the community by increasing its capacity, comfort and quality as a sporting venue.
The structural frame consists of main raker beams, frames or columns which are founded on solid rock, with seating panels and a box gutter frame bolted to a structure cast into the concrete, carrying a cantilevered roof.
Spanning about 30m, the cantilevered roof consists of triangular trusses, constructed from circular hollow sections. The trusses vary from 2m at the back to 500mm at the nose cone, with a curved bottom member. It has IPE profile purlins that span 9m (more or less the span of the raker beams) with curved cladding rails fixed to the back of the concrete frames, which carry the circular purlins that support the curved cladding.
The main challenge was casting in the structure that carries the gutter boxes at the back. Between the engineer, contractor and architect, a three-member connection was designed and each section had its own cleat made to align the trusses and achieve an even visual alignment.
Franco Mordini from the Association of Steel Tube and Pipe Manufacturers (ASTPM) commended the use of a double chord with a compression member where the loads are high, which converges into one chord where the loads are low, as well as the use of circular hollow section girts to the facias, which eliminates the use of a complicated sag system.
Client/owner/developer: Mangaung Municipality
Architect: Urban Edge Architects
Structural engineer: AECOM
Project manager, main contractor and quantity surveyor: WBHO
Structural steel detailer/detailing company: Construct Steelwork Detailing
Cladding supplier: Tate & Nicholson
Steelwork contractor and nominator: BRD Construction
Global Roofing Solutions metal cladding category
New head office for Statistics South Africa
Roof and side cladding on the new Statistics South Africa offices and archive building is 0,58mm thick Galvanized Z200 GRS Brownbuilt 406 profiled sheeting with standard Chromadek finish one side and standard backing coat on the other side. Sheeting colours include Dove Grey, Dark Dolphin and Charcoal. Insulation used over purlin on the roof and sides was 40mm thick, white-faced Lambdaboard and Sisalation 405.
Interestingly, all roof sheeting, side cladding and soffit sheeting are concealed-fix sheeting with the majority of flashings being concealed-fix or designed to hide fasteners. The most impressive technical aspect of this project is the underslung Brownbuilt 405 profiled sheeting in long lengths, tapered with angles, and special flashings.
Other challenges included an extremely congested site and short installation programme duration. The buildings were high, with lots of angles and direction changes. The main contractor assisted with cranage and special scaffolding. Another innovative solution included the design of special clip-on flashings.
Dennis White, director of the Southern African Metal Cladding and Roofing Association (SAMCRA), pointed out the unusual and interesting use of a profile that dates back to the 1960s, on the state-of-the-art modern building. “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.”
Architect: GLH Architects – Terra Ether JV
Structural engineer: Pure Consulting
Quantity surveyor: RLB / Pentad
Project manager: GLH Project Manager
Main contractor: STATS SA JV
Steelwork contractor and nominator: Cadcon (Pty) Ltd
Structural steel detailer/detailing company: Mondo Cané
Cladding contractor: Tate and Nicholson
Metal cladding supplier: Global Roofing Solutions
Paintwork: Dram Industrial Painter
Safintra factory and warehouse category
Mr Price Distribution Centre
Due to material availability at the time of construction, the design of the new distribution centre for Mr Price had to be changed at a very late stage and the erection programme fast-tracked.
The overall geometry of the trusses and girders was changed to suit normal transport conditions in order to avoid abnormal loads. The truss chords were made of back-to-back angles and spaced 200mm apart, with the internal members comprising of 200IPE and 200 x 75PFC. This lead to a very stiff truss, which meant that erection on site would go much faster as spreader beams were avoided.
Instead of having small monitors on the roof, it was decided that every alternate 30m bay would be raised 2,5m higher than the adjacent bay to form very large monitors, or simply a low-bay, high-bay design.
The warehouse used 200 tons of circular hollow section bracing in the roof, varying from as small as 114 x 4CHS right up to 406 x 10CHS.
Ultimately, the team had ten weeks fabrication lead time prior to erection commencement to get ±1 000t of fabricated material on site. Due to bad weather, the 90-day erection programme was further reduced to 82 days, including weekends and public holidays. With a total number of 2 754t to be installed, an average or 33,5t was erected per day, with the most tons erected in one day recorded at 76t.
Another challenge was the logistical co-ordination of the 75 000 assemblies that needed to be fabricated, painted, delivered and erected on site.
Client/owner/developer: Mr Price Group Limited
Architect: Paton Taylor Architects
Structural engineer: Arup
Quantity surveyor: Edgecombe & Hayes Hill (Pty) Ltd
Principle agent: Paton Taylor Architects
Main contractor: Stefanutti Stocks Building KZN
Steelwork contractor and nominator: Avellini Impact Joint Venture (Avellini Bros (Pty) Ltd / Impact Engineering (Pty) Ltd) Structural Steel Detailers / Detailing companies: 3DCon Steel Detailing (Pty) Ltd and Structech 3D Modelling
Cladding supplier: Kingspan
The Tree House Constantia
Steel was used to express the natural structural systems of the trees surrounding the Constantia Tree House, a highly customised, floating building accessed by a weathering steel bridge with a timber-deck walkway. A circular stair with sculptural treads carved from solid-standing laminate oak and supported on weathering steel reaches, links the living area below with the bedroom level above.
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 drum at ground level (where the building’s utilities are concealed behind a slatted timber screen).
Situated high on a slope without any direct vehicular or crane access meant that all the steel components had to be transported via narrow driveways, using both a sleigh and then chain blocks attached to two I-beams on the top of the scaffolding. Some of the larger components were winched up an embankment to the position of the construction site.
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.
Client/owner/developer: Graham Paarman
Architect and nominator: Malan Vorster Architecture Interior Design
Structural engineer: Henry Fagan & Vennote
Quantity surveyor: DA Quantity Surveyors
Main contractor: T Naude
Steelwork contractor: Link Engineering
Photographer: Micky Hoyle, Condé Nast House & Garden
Saint-Gobain Light Steel Frame (LSF) category
Joint winner: Mall of Africa, LSF facade and parapet walls
Speed and ease of construction was a requirement on what was one of the largest single phase building projects in the Southern Hemisphere, and the building programme required the building envelope to be closed within a few months. One of the biggest technical challenges faced by the engineers included the extra-large openings and unusually high parapet walls.
The structural framing consists of 0,8mm LSF, 90mm x 38mm cold-formed lip-channel profiles, assembled into wall panels on site, with typical 600mm x 600mm CTC grids. Frames placed slab to ceiling, column to column.
Cold-formed, thin-gauge steel frames were used for the lightweight design. A highlight was the architect’s requirement for protruding, horizontal plaster bands, some more than 100m in length, to wrap the building and be exactly in line, at a height of up to 25m.
Furthermore, a high R-value was required for the external cladding to achieve the required energy efficiency. From an environmental perspective, an energy-saving external thermal insulation and cladding system (ETICS) was used for the external cladding.
The wind load on the roof parapet walls, some 3m in height, was overcome with the reinforcement of wall panels by using an LSF joist, turned on its side. The use of LSF and EPS cladding requires less or no crane time, rapid installation, a reduced need for cleaning operations, and ensures weight reduction on the super structure resulting in savings of structural concrete. It provides a durable external cladding with low maintenance requirements.
Client/owner/developer: Atterbury Waterfall Investment Company
Architect: MDS Architecture
Structural engineer: HAGE
Quantity surveyor: NWS
Project manager: GHC Africa
Main contractor: Group 5 / WBHO
Steelwork contractor and nominator: Ohlhorst Light Building Solutions
Steelwork contractor: Clotan Steel
Cladding supplier: Weber Saint-Gobain
Joint winner: Temporary OPD Unit at Swaziland Government Hospital
Following a rational design to SANS 517 light steel frame (LSF) building, the LSF was manufactured 430km away from the site and due to site constraints, the LSF panels had to be delivered exactly in the sequence they were required on the site – any errors would result in considerable time delays.
The project site also had some challenges in terms of the topography, site access roads, sewage lines, storm-water systems and available space on site for the offloading and storage of building materials.
The scope of works included the rolling of about 100t of 0,8mm and 1,2mm LSF sections in Vereeniging and transporting it to Mbabane, as well as the erection of all the LSF panels including 16,5t of heavy structural steel, the erection of 2 198m² of external cladding and 7 512m² of internal lining comprising 15mm thick fire-stop and moisture-resistant Saint-Gobain Gypsum board, and the placement of the roof.
Two senior building inspectors from Swaziland attended the Southern African Light Steel Frame Association (SASFA) six-day training course for building contractors, which was presented in March in Gauteng.
Client/owner/developer: Micro Projects
Architect: Ramashka Investment (Pty) Architects and Interior Design
Structural engineer: Donnic Engineering
Quantity surveyor: Owen Thindwa & Associates
Project manager and nominator: Razorbill Properties 127 (Pty) Ltd
Main contractor: Sukabadzele Investments T/A Iceberg Contractors
Steelwork contractor: Razorbill Properties 127 (Pty) Ltd
Structural steel detailer / detailing company: Razorbill Holdings (Pty) Ltd
Cladding supplier 1: Saint-Gobain Gyproc
Cladding supplier 2: Pelican
Cladding supplier 3: Everite
Electrical and mechanical engineers: Mast Consulting Engineers
Full thanks and acknowledgement are given to SAISC for the information given to write this article.
Caption: The Eastgate Phase 2 Redevelopment won the commercial architectural category and was named overall winner.