Structural Steel Roof Over Blue Downs Swimming Pool

The Blue Downs swimming pool was developed in response to the City of Cape Town’s wish to provide a high-quality indoor public swimming pool to serve the Blue Downs community. It is intended that the pool should serve as both a general community facility as well a sporting facility for use during swimming competitions.

The design of the structural steel roof comprises a main roof over the swimming pool area, as well as adjacent subsidiary roofs over two separate public seating areas, an administration block and a lifeguard tower. The requirements of the architectural design were furthermore that the main roof should be supported only at the four corners, standing 35 metres apart on circular concrete water storage ‘silos’ (the silos are for storing rainwater run-off from the roof for use in the pool). Due to the architectural requirements and the large spans involved, it was considered that no other structural medium other than structural steel would be feasible.

The original architectural design called for a rounded double barrel-vault roof over the main swimming pool area, in accordance with which a thin shell-type roof structure was designed. Due to financial constraints and difficulty in engaging suit-able local steel fabricators prepared to carry out the work, which required extensive use of curved members, the design was subsequently revised during construction to the current pyramid shape. In carrying out the re-design, the new design was constrained to an extent by the configuration of the supporting reinforced concrete structure already constructed.
Because of the highly corrosive swimming pool environment, a duplex system of corrosion protection consisting of both hot-dip galvanising and painting was adopted. As the components of the toblerone trusses were too large for the galvanising bed, zinc metal spraying was used for these elements in lieu of hot dip galvanising. Inspection and testing of the zinc spray application was carried out by the Hot Dip Galvanizers Association in order to ensure compliance with the speci-fications.

The main roof as per the revised design and as constructed comprises the follow-ing main structural elements: Pitched ‘toblerone’-type trusses forming the four corners of the pyramid shape, edge girders, and sloping secondary trusses.
The toblerone trusses are the primary structural elements, spanning diagonally across the pool between the supporting silos, and intersecting at the roof apex. The trusses work in combined bending and axial loading and rely on the lateral resist-ance provided by the four support points. The trusses support the ends of the purlins, the ends of the secondary trusses, and the translucent sheeting forming the facetted corners of the roof. Because of the potential for buckling in the slender axially-loaded trusses, diagonal bracing was provided in the plane of the roof to provide lateral stability.

The edge girders are placed along the perimeter of the main roof. Besides support-ing the side cladding and the outer sections of the roof, the edge girders assist in resisting the lateral support reactions from the sloping toblerone trusses. The edge girders on two sides of the structure also support the top edges of the subsidiary roofs over the seating areas.
The secondary trusses support the roof purlins, and are in turn supported at their top ends by the toblerone trusses and at their lower ends by the edge girders. In addition to supporting the roof loads, the secondary trusses are also used to provide lateral support to the chords of the edge girders.
The architectural requirements were for the structural steelwork to be exposed and to make use as far as possible of circular tubular members in order to be aestheti-cally pleasing. All main structural elements with the exception of purlins and sheeting rails, and including all knee braces and diagonal bracing, have therefore been fabricated using circular hollow sections. With the numerous intersecting members, welded connections between intersecting tubular members were in some cases rather complex, requiring careful fabrication.

A number of technical challenges had to be overcome in both the design and the erection of the roof structure. Due to the large span of the main roof, vertical midspan deflections of almost 60mm could be expected in the four edge girders. The interface between the main roof and the side roofs therefore had to be designed to accommodate this relative movement. In the case of the roofs over the administration building and lifeguard tower, this was accomplished by separating the side roofs from the main roof, and accommodating the movement by provision of sliding flashing joints in the cladding.
The erection sequence was established in consultations between the engineer and the steel fabricator, taking cognisance of the requirements of the design. The edge girders and toblerone trusses intersect at common corner elements, and these elements had to be installed at the beginning of the erection process. 

The corner elements had to be accurately placed in order to ensure proper fitting of the various trusses and girders. Because the toblerone trusses rely on the edge girders to withstand the lateral support reactions, the four edge girders had to be erected beforehand. This meant that the toblerone trusses had to be installed while working over the edge girders. One of the toblerone trusses was installed, remaining temporarily propped until the intersecting truss could be installed to provide stability.

Once these main members were in place, the secondary trusses and other structural elements such as bracing members and purlins could be installed. Because the design allows little tolerance for dimensional discrepancies, a high level of input was required by the steel fabricator in order to achieve the required accuracies.

Project Team

Developer/ Owner: City of Cape Town
Architect: ARG Design
Structural Engineer: Bergstan South Africa
Quantity Surveyor: LWA Quantity Surveyors

(R/A Waterson & Hoosai cc)

Project Manager: ARG Design
Main Contractor: Tempani Construction (Pty) Ltd
Steelwork Contractor: Mazor Steel (Pty) Ltd

 

Time Square Maslow Hotel

 

Tons of structural steel used 700 tons
Structural profiles used Structural Hot Rolled, Tubular Steelwork up to 1000mm diameter, etc.

Project team

Project Team Role Company
Nominator Cadcon (Pty) Ltd
Client/ Developer Sun International
Architect LYT Architects
Structural Engineer WSP
Engineer WSP
Quantity Surveyor MLC
Project Manager Not provided by nominator
Main Contractor WBHO
Steelwork Contractor Cadcon (Pty) Ltd
Steel Erector On Par
Cladding Manufacturer Not provided by nominator
Cladding Supplier Not provided by nominator
Cladding Contractor Chartwell Roofing
Corrosion Protection
Galvanising
Not provided by nominator
Corrosion Protection
Paintwork Contractor
Dram Industrial Coatings
Photographer, Photo competition Sun International
Photographer, Other submitted images Not provided by nominator

If you were a part of this project, and your company details are incorrect or missing – please notify the SAISC so that the error can be corrected.

Future Africa Campus

Project Team

Project Team Role Company
Nominator TMW Fabrication
Client/ Developer University of Pretoria
Architect Earthworld
Structural Engineer WSP
Engineer Not provided by nominator
Quantity Surveyor Not provided by nominator
Project Manager Not provided by nominator
Main Contractor Robenco Construction
Steelwork Contractor Not provided by nominator
Steel Erector Not provided by nominator
Cladding Manufacturer Not provided by nominator
Cladding Supplier Not provided by nominator
Cladding Contractor Not provided by nominator
Corrosion Protection
Galvanising
Not provided by nominator
Corrosion Protection
Paintwork Contractor
Not provided by nominator

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Victor Daitz Mathematics Centre

The King Edward VII Mathematics Centre is located at King Edward VII School in Johannesburg. The project is a classroom facility with a hockey pavilion comprising both an upper viewing deck with kitchenette  facility and lower area of team ablution/change facilities, as well as a larger ablution facility for scholar use.

The brief to the architect was to propose a scheme as a fund raising platform from Old Boy donors. Two donors, Victor Daitz Trust and Edgar Droste Trust (both deceased Old Boys) stepped up to assist.

The project was to comprise initially 4 x mathematics classrooms and ablution facilities. This later expanded to incorporate a hockey pavilion and ablution facilities. The idea was to maximise the  small  space adjacent other classroom wings and minimise the number of peripatetic teachers.

From the outset, the project was envisaged as a combination of steel, concrete, brick and aluminium. The sunscreen roof was envisaged as a steel filigree screen with cutout patterns and as one of two elements which could give the project life, the aluminium balustrade being the other. The elements of geometry and mathematics are used here as an inspiration for the creation of their forms.

The steel elements of the project vary from Universal Columns to square hollow sections which are used as a giant order to the upper canopy roof to maximize the verticality as an offset to the flat canopy. The rafter and rear screen elements are IPE members and C-channels. The steel sheet canopy is suspended.

From an engineering perspective the challenges to the canopy roof were in the methodology in which the sheeting is suspended from its structure, as an inverted solution. The sheeting is read as a hovering plane that floats above the parapet walling at the building edge. The large over-sailing cantilever sheet at its point hangs off an extended beam and the framed system of beams and rafters. The cantilever similarly covers the passage way, whilst the hockey pavilion sheeting extends the roofline to match. The screen is grounded on double length columns which bypass the building and soar vertically straight to the canopy.

The challenges of fabrication were in the amount of steel sheet that was to be removed in the patterning. Too much cut out created a bend in the sheet, and as such the pattern had to be manually adjusted in order that it read as random, natural and poetic. Most of the panels therefore had individual patterning and as such this required close monitoring on the cutting and installation process.

The resulting aesthetic is a sensitive approach to mathematics and geometry which creates patterns in light and shade which varies constantly throughout the day and night. A visual delight juxtaposed to previous hard insensitive buildings.

The project team worked tightly together from project concept to project fruition. Both the  main  contractor and steel sub-contractor took the project on board as it was felt that it would be a challenge and something out of the ordinary for them to realize. The project team rose to the challenge and the process was fun.

We would like to think the results speak for themselves.

Tons of structural steel used 46t
Structural profiles used IPS, Universal Column and Universal Beam, Channels
Tons of LSF used 7t – Steel Framework, 2t (rafters)
Span of trusses and Kg/m2 (if applicable) Rafter spans – cumulatively 132m
Profiles used IPE Rafters, C-Channels
Cladding profile/ type used 2mm Stainless Steel sheet – Grade 409.
Cladding area/ coverage and tonnage 280m2 – 11.6t

Project Team

Project Team Role Company
Nominator StudioJoy+ Architects
Client/ Developer Business Manager – King

Edward VII School

Architect StudioJoy+Architects
Structural Engineer eStruct Consulting
Engineer eStruct Consulting
Quantity Surveyor Stuart Ray Skead Associates
Project Manager Not provided by nominator
Main Contractor Akhane Construction (Pty) Ltd
Steelwork Contractor Hybrid Africa
Steel Erector Hybrid Africa
Cladding

Manufacturer

Metal Graphics
Cladding Supplier STALCOR
Cladding Contractor Hybrid Africa
Corrosion Protection

Galvanising

Hybrid Africa
Corrosion Protection

Paintwork Contractor

Hybrid Africa
Photographer, Photo

competition

StudioJoy+Architects/Terse

Photography

Photographer, Other

submitted images

StudioJoy+Architects

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V&A Grain Silo Complex façade

What is the purpose of the structure/ project?

 The V&A Grain Silo was built in the 1920s to store grain for export out of South Africa. This industrial heritage complex was rejuvenated as the central feature of the world class green Silo District development. Heatherwick Studio was engaged to conceptualise the redevelopment that is now occupied by The Zeitz Museum of Contemporary African Art (MOCAA) and The Silo Hotel.

The most noticeable and significant aspect of the use of steelwork on the project are the 82 pillow windows on the building. These are installed to the rooms and restaurant of The Silo Hotel and on the top floor of the Zeitz MOCAA. The windows on the restaurant level of the hotel are 3.8m wide x 5m high and the windows to the hotel rooms are 3.5m wide and range in height 5m – 3.8m.

On the top floor of the Zeitz MOCAA the windows are 4.9m wide x 5m high and include corner windows consisting of two halves, 3.4m wide x 5m high, which are bolted together and sealed on site. Other significant use of steelwork in the façade packages include:

Zig-zag windows: Folded glass windows built into the silo walls at the museum ground floor, supported by steel flat plate structure.

Trafficable skylights: 12 trafficable glass panels supported by steel structure to the top of the silos over the museum atrium

Skylight: Glass skylight between the  silo building and elevator building supported by steel structure

What was the brief to the architect?

 Heatherwick Studio’s brief was to give new life to the redundant industrial building, repurposing it into something new for the waterfront. Following the studio’s suggestion of installing convex windows into the upper storeys of the building to transform it into a glowing beacon for the waterfront and afar, Arup further developed the concept of the pillowed windows.

Was the project envisaged in steel from the start? If not – why was it built in steel in the end?

For the pillow windows alternatives to steel were explored, such as aluminium. Steel was selected because of:

The capacity of local industry to carry out this work to the required tolerances

Robustness of steel welding, which is not subject to reduced strength in the heat affected zone as is the case with aluminium.

Cost effective for the complex geometry.

Give a brief description of the structural framing. What type of sections were used (e.g. hollow, cellular, I beams etc) and why?  

The pillow windows are fabricated from flat steel plates 50 x 16 that are welded to one another to form the bulging geometry of the pillow and welded to the 160 x 80  rectangular hollow section (RHS) forming the perimeter frame. The choice of flat bars / plate was to minimise the appearance of the framing from inside and maximise the views through the window. The frames are positioned at each facet between the glass panels, with the depth of the plate orientated toward the room and roughly perpendicular to the bulging geometry. Aluminium glazing profiles where mechanically fixed to tapped holes on the outer edge of the flat bars / plates. The flat bars act as domed arching structure for wind loads carrying axial loads and bending moments. The perimeter RHS provided additional width for the perimeter weather proofing and structural strength for transferring the framing wind loads to the four steel brackets used for fixing the window to the concrete structure. The perimeter frame also included a temporary hoisting bracket bolted to the frame during hoisting.

The window includes double glazed triangular panes, structural silicone bonded to the aluminium glazing profile  on the outside face of the steel frames. These window panels were installed in the factory and the windows were transported and installed fully glazed and sealed.

Were there any challenges in the fabrication of the project from the engineer’s design – if yes, please tell?

Achieving the pillow window geometry was the most significant challenge. The steelwork geometry was defined in detail by Heatherwick Studio and Arup using parametric 3D modelling techniques. This allowed the fabrication aspects, such as orientation of framing and alignment of framing at joints mitre lines to be established in a 3d model developed by Arup, while allowing the geometric parameters, such as the geometry of the bulge, framing positions and window size to be fully defined by Heatherwick Studio.

The parametric model was used to generate a 3D model of each of the five window frames, that included the required member size and orientation that was provided to Mazor, the steelwork fabricator, to produce their steelwork shop drawings.

Building this complex geometry was a challenge that was tackled by Mazor through production of steel jigs to define the geometry of each of the window frames. The steel members were assembled into the jig and tack welded into place, removed from the jig and then the welding completed. Careful planning was required in fabrication of the jig and planning of the welding to ensure that all welds could be accessed and welded after the framing was tack welded together. To achieve the neat appearance at the joints welding splatter at these positions was ground smooth and the joints body filled to achieve a high level of quality at these nodes. Mazor had a specialist team responsible only on dressing and shaping each of these nodes on all the windows.

Transporting and installing was another challenge as the pillows were made and glazed as one assembly in a factory (up to 5074mm x 5022mm in size) and transported to site complete. Careful handling was required to ensure that the glass was not damaged in the process. With the window fitting tightly between the concrete beams and columns and inside of the concrete, façade installation was challenging. To reduce the risks it was desirable that the position of the windows during hoisting was similar to installation position of the window and that the hoisting cables did not clash with the concrete structure. To achieve this the design incorporated a temporary lifting bracket, bolted to the perimeter frame,  that aligned  the centre of gravity of the glazed window with the lifting cables, which also positioned the cables outside the concrete face.

What is special/ unusual/ innovative/ aesthetic about the steelwork/cladding in this project?

The use of parametric 3D modelling techniques that respected the detail fabrication considerations for the steelwork assembly and also enabled the architect to shape the desired geometry.

Complex geometry achieved with steelwork fabrication.

Quality of finishing achieved particularly at the nodes as a result of the 3D modelling considerations and the finish quality achieved by the contractor.

Rejuvenating the Grain Silo in such an architecturally astonishing manner has created a unique centrepiece for the Silo District.

How did the project team work together (e.g contractor involved early, challenges/ ease of communication etc.)

Close collaboration with the architect was necessary to realise technically challenging design intent in a pragmatic and buildable manner. Key to this collaboration was combining Arup’s deep design knowledge with market leading parametric capability to create a model that allowed the architects to drive the aesthetic resolution within a technically feasible framework.

Understanding the geometry to high level of detail before tendering ensured that the desired outcome. Communicating the design intent to the contractor and reviewing the contractor’s 3D shop drawing model shortened the shop drawing review phase and allowed for comparison of the design intent model and shop drawings model a 3D virtual environment rather than on 2D drawings, lessening the possibility of errors.

Tons of structural steel used Pillow windows: 82 windows, 5 different types total 63.8 tons

Zig-zag windows: 3.1 tons

Trafficable skylights: 9 units 1.5 tons each = 13.5 tons

Skylight: 2.2 tons

Structural profiles used Pillow windows: 160×80 RHS & 50×16 plate

Zig-zag windows: Flat plate 150×12 & 120×12

Trafficable skylights: 200×100 RHS / 102x203x23 T / 200 PFC

Skylight: 230x133x25 UB

Project Team:

Project Team Role Company
Nominator Arup (Pty) Ltd
Client/ Developer V&A Waterfront
Architect Heatherwick Studio
Structural engineer for façade steelwork in this entry Arup (Pty) Ltd
Quantity Surveyor MLC
Project Manager Mace
Main Contractor WBHO
Steelwork Contractor & erector (pillows, zigzag windows) Mazor
Steel contractor & erector (skylights) Mazor
Cladding Manufacturer Mazor
Cladding Supplier Mazor
Cladding Contractor Mazor
Photographer, Photo competition Arup (Pty) Ltd
Photographer, Other submitted images Arup (Pty) Ltd

 If you were a part of this project, and your company details are incorrect or missing – please notify the SAISC so that the error can be corrected.

Stortemelk Hydropower

Architect’s Motivation
Situated in the rolling foothills of the Drakensberg Mountains, along the banks of the Ash River, the Stortemelk Hydroelectric Plant attempts to celebrate the importance the plant holds in producing clean, responsible electricity in South Africa.

Comprised of a number of building skins, the design approach intended to create different experiences of the plant from the exterior, & from within the interior. Clad in Corten Steel & Polycarbonate sheeting, the architecture is intended to be of its landscape, while still allowing for good light quality to penetrate into the plant interior. Articulating the façade with slotted window openings allowed for the perception that the electrical production of the plant is spilling out into the surrounding environment, creating a beacon in the landscape.

On approach to the site, the Corten Sheeting reaches up into the skyline, announcing the building & adjacent river from a distance. The lightness of the steel construction is then contrasted by the far more stereotomic design of the rest of the plant, which protrudes from the river bank as a plinth.

The challenge in the project was to create spaces for production, with minimal human interaction. Working hand-in-hand with an exceptional client made the realization of this celebration of production possible, creating architecture with respect for the responsible electrical generation the client creates.

Client motivation:
Our company carries a certain ethos that is core to every enterprise we undertake, namely the responsible production of energy in a South African context.

Our brief for the Ash River site was to create a housing for a hydro-electric plant that blended seamlessly with the surrounding landscape while also celebrating the responsible production of electricity. Many of our hydroelectric sites have been in operation for decades, which therefore require an approach that does not become a burden on the landscape or surrounding community.

The response to this brief from the architect achieved every aspect that we required, succeeding in both blending into the landscape, while also celebrating the plant’s functions. Beyond this, the design managed to create a spectacular light quality in the work areas of the plant through the use of polycarbonate sheeting.

The plant stands as the perfect mediation between the production of electricity from the river, & a well-considered addition to the Golden Gate landscape. In its entirety we believe this piece of production architecture fits wholly within our ethos of responsible creation, standing as a testament to what can be achieved without negatively affecting our unique countryside.

Profiles used 406 x 140 x 46mm galvanized steel I-Beams & Columns, IPE-AA 120 galvanized, IPE 200
Type of cladding 3mm Corten sheet panels & polycarbonate sheeting

Project Team

Project Team Role Company
Nominator earthworld architects & interiors
Client/ Developer REH Group
Architect earthworld architects & interiors
Structural Engineer Aurecon
Engineer Not provided by nominator
Quantity Surveyor Not provided by nominator
Project Manager Not provided by nominator
Main Contractor Eigenbau
Steelwork Contractor Not provided by nominator
Steel Erector Not provided by nominator
Cladding Manufacturer Not provided by nominator
Cladding Supplier Not provided by nominator
Cladding Contractor Not provided by nominator
Corrosion Protection
Galvanising
Not provided by nominator
Corrosion Protection
Paintwork Contractor
Not provided by nominator
Photographer, Photo competition Charles Corbett Photography
Photographer, Other submitted images earthworld architects & interiors

If you were a part of this project, and your company details are incorrect or missing – please notify the SAISC so that the error can be corrected.

Soweto Sports Centre

What is the purpose of the structure/ project?

A multi-purpose sports arena

What was the brief to the architect?

A multi-purpose sports arena for the Soweto community, to be able to practice various disciplines of sports in a world-class arena

Were there any challenges in the fabrication of the project from the engineer’s design – if yes, please tell? Tell more about fabrication and erection process if it was complex, difficult, innovative etc.

Design and fabrication of flashings and interfaces on site.

What is special/ unusual/ innovative/ aesthetic about the steelwork/cladding in this project?

Multi-angle interface of side cladding

Cladding profile/ type used SAFLOK 700
Cladding area/ coverage and tonnage 2500M²

Project team

Project Team Role Company
Nominator Safintra
Client/ Developer Not provided by nominator
Architect Iyer Architects
Structural Engineer Not provided by nominator
Engineer Archway Projects
Quantity Surveyor Not provided by nominator
Project Manager Not provided by nominator
Main Contractor Shomang Construction
Steelwork Contractor Not provided by nominator
Steel Erector Not provided by nominator
Cladding Manufacturer Safintra South Africa
Cladding Supplier Safintra South Africa
Cladding Contractor RSS Roofing
Corrosion Protection
Galvanising
Not provided by nominator
Corrosion Protection
Paintwork Contractor
Not provided by nominator
Photographer, Photo competition Sublime Film
Photographer, Other submitted images Not provided by nominator

If you were a part of this project, and your company details are incorrect or missing – please notify the SAISC so that the error can be corrected.

Silo 3 and 4

No. 3 Silo consists of three independent apartment towers containing 79 high end apartments over 11 floors. The three towers are connected by two steel framed lift and stair cores enclosed in expanded aluminium mesh, providing spectacular views of the harbour and V+A precinct.

Silo 4 essentially forms the base for the apartment towers and contains an upmarket gym facility over two floors. A double volume pool pavilion faces onto Silo Square, with panoramic views of the new Zeitz MOCAA Gallery, Silo Hotel and surrounding Silo District public spaces.

Expressed materiality and appropriate detailing were considerations equally as important as resolving the functional and programmatic requirements of the brief.

The character of the building was developed as an interpretation of the inherent “gees, (or ‘spirit’), of the precinct as part of a working harbour. In response to the surrounding built environment, the team explored further the themes of ‘fit for purpose, working harbour elements’, and in its making exploited the possibilities of composite structures – concrete and steel working together – in order to maximise the clear floor to ceiling dimensions of the apartments. Concrete up or downstand beams were entirely avoided in order to maximise the views out all of the Apartments, bearing in mind the overall height restrictions imposed by the Planning regulations and consents achieved. Furthermore, in order to construct the expansive floor plates, without resorting to more concrete columns and beams, steel framing ‘tied back’ to the central shear concrete cores, is used to assist in accommodating the floor plate cantilever. This ‘additional steel’, has been consciously ‘picked out’ in colours referencing the cranes and other elements of working machinery in the surrounding dock yards.

The cast-in load bearing steel frames primarily consist of 50mm diameter solid carbon steel bars, adjustable custom reverse thread couplers, welded up 230×90 PFC frames, 203x203x46 H columns and intricate welded end plate connections. Solid bars were chosen for the high tension capacity with minimal lengthening when fully loaded and the custom couplers were chosen to allow for tolerance and future adjustability. The Virgin Active steel roof structure is made up of PFC girders and trusses with solid round bar cross bracing. The exposed round bar cross bracing aesthetic was followed through on the external steel stairs, steel lift shaft structures and the external walkway bridge.  

The installation and sequencing of the load bearing steel frames were by far the greatest steel related challenges faced on site. These frames were designed to work compositely with the concrete structure resulting overall in a more slender structure. These frames were installed concurrently with the concrete structure which impacted on sequencing of slab construction, post-tensioning and temporary backpropping. The interface between concrete and steel required works to be highly accurate to achieve the desired aesthetic of exposed steel and raw concrete as well as work compositely as intended. Communication and co-ordination between the architects, structural engineer, main contractor and steel sub-contractor early on in the project was instrumental in achieving this.

The steel components used throughout the building are integral to the building’s structural integrity. This is expressed through the bold use of colour, further highlighting the key ‘elements’ in the structural assembly. Yellow is used on the façade steel elements that support the cantilevering balcony concrete slabs, while red highlights the two circulation cores connecting the three towers.

Cladding materials, including Rheinzink and perforated metal panels were also selected to respond to the harbour industrial shed aesthetic.

The collaboration of consultants, contractors, sub-contractors, specialist advisors and client was integral to the successful completion of No.s 3&4 Silo.

Revit was used as a production tool by all consultants (as was required by the client), and allowed the sharing of a central digital model across all disciplines.

Tons of structural steel used 320.392
Structural profiles used Solid bars, PFCs,H & I sections, angles, cold formed lipped channels

Project Team

Project Team Role Company
Nominator Sutherland
Client/ Developer V&A Waterfront
Architect VDMMA & Makeka Design Lab
Structural Engineer Sutherland Engineers
Quantity Surveyor MLC
Project Manager MACE
Main Contractor WBHO
Steelwork Contractor LJ Le Roux Industries
Steel Erector LJ Le Roux Industries
Corrosion Protection
Galvanising
Advanced Galvanizing
Corrosion Protection
Paintwork Contractor
MRH Group
Photographer, Photo competition VDMMA

If you were a part of this project, and your company details are incorrect or missing – please notify the SAISC so that the error can be corrected.

Rosebank Link

What is the purpose of the structure/project?

At 15 stories above the ground, the building consists of two basement parking levels, a ground floor or public/retail level, five parkade levels, and nine stories of offices from a podium level. It will allow everyday pedestrians to traverse without barriers from the Gautrain through to the adjacent malls.

What was the brief to the Architect?

As a building standing foremost in the center of a developing cosmopolitan area, the client wanted to have a unique building that served the needs of the client, its neighbors, as well as the public in a new, exciting, and smart way.

Was the project envisaged in steel from the start? If not, why was it built in steel in the end?

Yes, Meeting Pods, Atrium, and Media screen.

Meeting Pods:  The Meeting Pods can be viewed from the landscaped thoroughfare which forms part of the showpiece of the buildings. The architectural intent for the pods is to be as open as possible, embedded in the glass. These pods are also cantilevered from the concrete frame and was a retrofit.

Atrium:  The Atrium structure formed part of the glass façade, spanning over six stories, additionally it formed a part of the glass skylight structure on the Atrium roof. The structure spanned large distances and had to be as slender as possible while limiting deflection.

Media screen:  The LED panels required special connections at very particular points, while constrained by the removal time by the crane, steel allowed achieving these challenges.

Give a brief description of the structural framing. What type of sections were used (e.g. hollow, cellular, I-beams etc) and why?

Meeting pods:  Gravity loads were the main consideration; therefore, the loads were concentrated around one axis and normal I-section portals bolted to the concrete were the most efficient.

Atrium:  The inner–and bottom chord of the Atrium vertical truss and roof truss were determined by architectural constraints. The outer chord is braced by transom beams for the façade glass, however, the inner chord had a large unbraced length due to the omission of regular knee-bracing. Similarly, the bottom chord had a large effective length for the uplift load case, due to knee bracing not being able to pierce the bulkheads of the skylights butting up snug to the truss either side. This resulted in a relatively large PFC inner chord and large I-section for a bottom chord. The purlins (bracing for the top chord) of the roof had to step, due to the skylight glass line and sheeting line being on different levels. Additionally, the purlins form part of the skylight substructure. The load path was fairly two dimensional and an RHS section was used. For the Atrium glass transoms, large SHS were used due to the wind, and gravity load cases being very similar correlating the sections’ similar radii of gyration in each direction, it was also aesthetically preferred.

Media screen:  The screen consisted of a large SHS outer frame, as the facade and surrounding over cladding required a 200mm flat fixing face, it was also beneficial at the one end, as a part of the screen had to remain cantilevered to span across the crane void, which would only be filled later with structure. Considering hollow sections’ optimal spread of material away from the center of gravity it gave good results when relating stiffness/size ratios.

Were there any challenges in the fabrication of the project from the Engineer’s design – if yes, please tell? Tell more about fabrication and erection process if it was complex, difficult, innovative etc.

The manufacturing was straightforward, the main difficulty was during erection, the site has virtually no laydown areas with very limited access. The internal cladding support was all done by hand, accurate setting out of beveled columns gave a suitable platform to fix the substructure at awkward angles and positions as per the Architect’s design. The main Atrium roof is very high, and tower cranes were relied on for erection, difficulties were accessed and space as well as supporting lattice columns until the trusses were fixed in place.

What is special/ unusual/ innovative/ aesthetic about the steelwork/cladding in this project?

The final steelwork visual was not part of the architectural intent, therefore hiding it as effectively as possible while forming part of multiple systems and serving its purpose. To accommodate this architecture, it resulted in large unbraced lengths and a peculiar arrangement of members. There was also a large emphasis on keeping the tonnage down to accommodate the Green Star rating.

How did the project team work together (e.g Contractor involved early, challenges/ease of communication etc.)?

Design stage:   The Engineer and Architect liaised and correlated intent and final design with BIM level two, this was vital to ensure clash detection as the complex facade shapes where hard to interpret on two-dimensional drawings.

Shop drawing stage:  Even though detailed sheets were prepared, it was almost completely unused at this stage. Since such a large emphasis was placed on BIM, the model was an accurate reflection of the drawings. This allowed the Structural Steel Detailers to use the engineering model and import it straight into Tekla Structures software. Member lengths, connections, and positions translated from the model kept turnaround times for shop drawings and queries to a minimum. It also resulted in industry standard repercussions, where certain information pertaining to the length of the member can be omitted from engineering drawings and can technically only be used for design intent and setting out purposes.

Erection stage:  The Engineer worked directly with the Sub-Contractor to ensure the complexity of the information was carried over to the final item. BIM was also used on site, as the model was issued directly to the Sub-Contractor, allowing them to interrogate the model on site.

Tons of structural steel used 115 Tons
Structural profiles used All readily available profiles

Project Team

Project Team Role Company
Nominator KRU Detailing CC
Client/ Developer Redefine
Architect Paragon Group
Structural Steel Detailer KRU Detailing CC
Structural Engineer Sutherland
Engineer Sutherland
Quantity Surveyor MLC
Project Manager WBHO
Main Contractor WBHO
Steelwork Contractor Central Welding Works
Steel Erector Central Welding Works
Cladding Manufacturer Façade Solutions
Cladding Supplier Façade Solutions
Cladding Contractor Façade Solutions

If you were a part of this project, and your company details are incorrect or missing – please notify the SAISC so that the error can be corrected.

Rissik Street Post Office

What is the purpose of the structure/ project?

The structural steel is intended to act as a supporting frame of the existing building as it was previously damaged by fire in 2009.

What was the brief to the architect?

To restore the post office landmark to its former glory.

Was the project envisaged in steel from the start? If not – why was it built in steel in the end?

Yes as this was the most effective way of achieving the desired support within the existing structure.

Give a brief description of the structural framing. What type of sections were used (e.g. hollow, cellular, I beams etc) and why?

305*305*97 UC was used for the supporting columns that tied into the existing brickwork. Channels and angles made up the girders that support the floors in the upper levels of the building.

Were there any challenges in the fabrication of the project from the engineer’s design – if yes, please tell? Tell more about fabrication and erection process if it was complex, difficult, innovative etc.

The greatest challenge on this project was the allowed space to conduct the works in a safe and secure manner. As this was a restoration project great care had to be taken in the erection of the structural steel as these were to create support for the entire structure. Each of the structural members had to be measured on site to allow for precision fabrication further to the installation each section had to be monitored due to the damage caused by the fire in 2009 – special care had to be taken with the installation of the steel members and the connections to ensure sufficient and strong support. 

What is special/ unusual/ innovative/ aesthetic about the steelwork/cladding

in this project?

The post office was constructed in 1897 and has survived several disasters over the years, implementing the structural steel as a support structure within the existing building allows for the building to be structurally sound and prevents previous damage from compromising the integrity further. 

How did the project team work together (e.g contractor involved early, challenges/ ease of communication etc.)

All parties from start to finish worked in an orderly and disciplined manner allowing each trade to follow the other. Also allowing for multiple trades to conduct works simultaneously within a confined space.

Tons of structural steel used 130 TONS
Structural profiles used UB, UC, ANGLES

Project Team

Project Team Role Company
Nominator MPW STEEL CONSTRUCTION
Client/ Developer CITY OF JOHANNESBURG
Architect PARADIGN ARCHITECTS
Structural Engineer ASAKHENI CONSULTING ENGINEERS
Engineer Not provided by nominator
Quantity Surveyor Not provided by nominator
Project Manager Not provided by nominator
Main Contractor INKANYELI
Steelwork Contractor MPW STEEL CONSTRUCTION
Steel Erector MPW STEEL CONSTRUCTION
Cladding Manufacturer Not provided by nominator
Cladding Supplier Not provided by nominator
Cladding Contractor Not provided by nominator
Corrosion Protection
Galvanising
Not provided by nominator
Corrosion Protection
Paintwork Contractor
Not provided by nominator
Photographer, Photo competition MPW STEEL CONSTRUCTION
Photographer, Other submitted images Not provided by nominator

If you were a part of this project, and your company details are incorrect or missing – please notify the SAISC so that the error can be corrected.