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


Makro Riversands

What is the purpose of the structure/ project?

The structure serves as a retail centre.

What was the brief to the architect?

To maximize space utilization and minimize construction time.

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

The main roof structure consists of girders and castellated rafters. Castellated beams were used for aesthetics and to reduce the overall weight of the sections along the span. Also to increase the spanning capabilities.CHS were used in the barrel vaults as an architectural feature.

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 fabrication of the barrel vault needed to be completed to a tight tolerance in order to ensure correct fitment of barrel vault sky –lights.

It was complex due to the fast-track nature of the project. Whereby close coordination was required between the civil contractor, steel contractor, building contractor, sheeting contractor, fire services, mechanical services in order for the works to be completed in the required sequence within the building footprint.

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

The structural steel barrel vault arches on Makro structures have become a nationwide symbol of the Makro brand.

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

MPW detailing office worked in close communication with the engineering and architecture team in order to ensure discrepancies were picked up within the detailing phase, to allow for adjustments to be made prior to fabrication. This resulted in a structural system which very closely resembled a Mecano set. Therefore it allowed us to reduce erection time on site. All contractors on site worked in close unison moving from section to section ensuring all the requirements were met timeously.

Tons of structural steel used 480 TONS
Structural profiles used CASTELLATED, TUBING, UC, UB

Project team

Project Team Role Company
Nominator MPW Steel Construction
Client/ Developer Makro / Century Properties
Architect R&L Architects
Structural Engineer L&S Consulting
Engineer Not provided by nominator
Quantity Surveyor Not provided by nominator
Project Manager MPW Steel Construction
Main Contractor Concor
Steelwork Contractor MPW Steel Construction
Steel Erector MPW Steel Construction
Cladding Manufacturer Grs
Cladding Supplier Grs
Cladding Contractor Roofing Guarantee 
Corrosion Protection
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.

Whalecoast Mall

What is the purpose of the structure/ project?

Regional Retail Centre

What was the brief to the architect?

Provide a First Class Retail Centre, providing a welcoming shopping experience. A cinema / theatre is mandatory to the development. Aesthetic of the centre is to compliment the area and not detract from the natural beauty of the surrounding environment. Building is not to overpower the site and block all views of the coastline from the R43. The centre is to accommodate for the local and outlying neighbourhoods, sufficient amenities and parking is to be provided to do this efficiently and provide users with a good shopping experience.

How did the project team work together?

Concept design co-ordinated between the Architect and Structural Engineer. Structural Engineer together with Steel contractor and Contractor workshopped concept to make use of the lightest structural members without compromising the aesthetic and function required by the Architect and Client. Models were shared to assist in reducing clashes on site and reducing on-site alterations to prefabricated steel.

Tons of structural steel used 784 ton

(including wall stiffeners and shopfront supports)

Structural profiles used Mainly I’s, H’s, C’s and angles, Cold-formed lipped channel purlins. Circular hollow sections


Cladding profile/ type used Cladding Profile:( Material: 0.53mm Colorbond Ultra Matt) ( Profile: Saflok 700) by Safintra Roofing.


Cladding area/ coverage and tonnage 33 000m²

Project Team

Project Team Role Company
Nominator Safintra
Client/ Developer Whale Coast Village Mall (Pty) Ltd

HCI Propcom (Pty) Ltd

Sandbaai Development Trust

Shoprite Checkers

Architect JL Design

Bentel Associates International

Structural Engineer Bigen Africa Services (Pty) Ltd
Quantity Surveyor MLC Quantity Surveyors
Project Manager MDSA Project Management
Main Contractor Isipani Construction
Steelwork Contractor Mazor
Steel Erector Mazor
Cladding Manufacturer Safintra Roofing
Cladding Supplier Safintra Roofing
Cladding Contractor Cladco Projects
Photographer, Photo competition Fourth Wall Photography

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.

Videojet Paarl

What is the purpose of the structure/ project?
We were briefed to design the new VideoJet Paarl office and workshop, which is to set the tone for the future of this subdivision of the HG Molenaar brand. The location set at Driebergen Lane,Dal Josafat, on the street face of an existing factory setup, and needed to integrate itself with the existing building. HG Molenaar are pioneers in food process machines, and have the ability to manufacture any high end steel features – this project, would thus, as a showcase for their ability, in a new area of construction, be a sample for their existing and prospective clients, to assert instant respect, trust and faith, in HG Molenaar, to deliver what they promise.

The building is used as an office space, reception and workshop for the VideoJet brand, its MD, support staff and sales components.

What was the brief to the architect?
Iconic building that can be manufactured by HG Molenaar – ie use a lot of steel

Was the project envisaged in steel from the start? If not – why was it built in steel in the end?
Yes it was simpler to connect to the existing steel structure, the client could make the structure, and it would be faster.

Give a brief description of the structural framing. What type of sections were used (e.g. hollow, cellular, I beams etc) and why?
IPE 200 – Mainly – this section is considered for its aesthetic appeal as its structural strength – client wants to add on third floor at some stage
305x165x40 I Sections – All Beams
406x140x46 I Section – for its Cantilever
101.6×4.0 CHS Struts on Custom plates – with custom turned steel connections
25 Dia Solid rounds to Hang the bridge and floors
Y10 and Y12 Structural Steel to concrete reinforcement
Façade Lazercut screens by client hung on Steel angles – Sheets are 3000x1500x2mm Mild Steel

Give a brief description of the cladding process (complexity, difficulty, innovation etc)
Complexity – this was simple, we cut a few sample panels to see how we would fix, and whether the apertures were working – also checked the robust nature against potential theft and vandalism. The answer was simple – the design was very difficult to pin down with many stakeholders and opinions.
Innovation – simply used available technology – screens assist in controlling light and vandalism to glass facade

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.
At some stage there was a small 2-3cm discrepancy in height – the entire structure was jacked up and the error rectified with spacers.

What is special/ unusual/ innovative/ aesthetic about the steelwork/cladding in this project?
All steel was worked and machined on site. The client’s involvement assisted greatly with the process. It was also 3-dimensionally pinpointed prior to construction – so the fixing and bolting was a precise mathematic.

How did the project team work together (e.g contractor involved early, challenges/ ease of communication etc.)
Entire building was documented up front – no variations, no site supervision, no changes – smooth simple exact.

 Tons of structural steel used +- 2 ton
Structural profiles used US203*203*46
 Cladding profile/ type used Sheet metal epoxy coated 2mm with lasercut profile
 Cladding area/ coverage and tonnage 175.6sm², 4.95T

 Project Team

Project Team Role Company
Nominator Emerging Architecture
Client/ Developer HG Molenaar – Videojet
Architect Emerging Architecture
Structural Engineer Ekon Engineers and Project


Engineer    Not provided by nominator
Quantity Surveyor    Not provided by nominator
Project Manager    Not provided by nominator
Main Contractor T R S Construction
Steelwork Contractor HG Molenaar
Steel Erector HG Molenaar


HG Molenaar

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
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.

Our Lady of Lourdes – Rivonia Church

What is the purpose of the structure/project?

A new Roman Catholic Church with exceptional acoustics, despite the exterior weather conditions.

What was the brief to the Architect?

The brief to the project team was to design a long span octagonal roof, acoustically insulated from rain and hail sound effects.  The brief included the design of a complex shaped and vaulted ceiling below, also designed with specific acoustic properties.  A specialist Acoustic Consultant was employed  to assist in the form and specification of the roof coverings as well as ceiling below.  A Sound Reinforcement Consultant also advised on the church space and acoustic ceiling above.

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

Yes.  Early design options for a tiled roof were discounted at the inception of the project.

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

The roof design was made more complicated by the planned shape of the building itself, not being asymmetrical octagon but rather an adjusted one. This design could not rely on pure symmetry and a lot of effort was spent with the Structural Steel Detailers, KRU Detailing, to draw and detail all the components.

The fact that the springing point of the roof was at 6.95m above the slab level, and that the concrete work at roof level comprised of two complex rings of reinforced concrete “loops” supported on linked column frames, required planned tolerance between the steel/concrete face and much survey effort was undertaken by the builder and Sub-Contractors to ensure a first time fit at the high level.

The ceiling below was also required to be supported on a secondary structural steel grid.  The centroid and shape of the ceiling profile did not match the shape of the roof, with slopes and acoustic performance requiring support work, positioning the steel grid well away from trusses and cladding supports, considerably over-complicating the design and erection process.

Give a brief description of the cladding process (complexity, difficulty, innovation etc).

The roof cladding, on the advice of a multidisciplinary team led by the Engineer, was for lightweight concealed fix roof cladding, designed around the partly asymmetrical octagonal roof, built tightly over a special taped gypsum sandwich layer, specified by the Acoustic Consultant, the sound damping system was to be tightly below the metal cladding.

This design was configured to damp excessive noise from rain and hail during the future church services.  The gypsum was in turn supported on its own metal gridwork, all fixed to the steel roof at the highest level.  Spans and spacings were critical, with the roof cladding requiring a different support work spacing from the gypsum layers below.

The acoustic ceiling below was designed to a complex shape, in turn requiring a different grid configuration and shape from the girders and supports above.

The ceiling required movement and control joints as part of the design specification, with the metal grid work between steelwork and the acoustic ceiling itself being “weakened” at the critical positions of the larger radial joints to ensure the performance of the actual ceiling joints below.  The ceiling would not be readily accessible from below for cleaning and maintenance purposes due to the configuration and layout of the seating for the congregation.

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 sheer complexity of the roof, the two independent levels of structure (at cladding level and much lower down at acoustic ceiling level), the substantially different shapes of the two structural elements, the moderately long spans, structural heights, moderate-high loads, and all design complicated matters.

The site of the new Church has a severe grade of around some eight percent, also had planned stepped terraces.  This required quite complex construction arrangements, affecting the delivery of materials, site storage and the steelwork erection process itself.

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

The roof cladding itself required to reflect the “look” of old weathered copper-roofed churches, and the complex vaulted and shaped acoustic ceiling below were conceived by a specialist experienced ecclesiastical Architect and executed by the project team, led by the Structural Engineer.

A specialist Acoustic Engineer was consulted to assist with shape and material of the roof cladding as well as the ceiling below.  The requirement for special acoustic cladding at roof level, with the unique acoustic shape and material at ceiling level below, provided quite a challenge that was successfully solved by the Designers and Contractors.

The rainwater goods and concealed downpipe pipes required intricate detailing and planning.  The gutters were designed as part of the external cladding shapes and the collection and vertical reticulation of stormwater integrated into the frame and cladding of the building.  The downpipes are hidden in the structural support columns but linked back to the gutters, which in turn, were provided with long life urethane coatings.  An overflow capability was built into the gutter design to cope with larger design storms and hail precipitation.

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

The Contractor was consulted immediately after tender.  The tender documents were especially drawn up by the Quantity Surveyor firm, Norval Wentzel Steinberg, around the complex shape, and working drawings were included in the documents (for the upper-level structures only – the ceiling supports were added post tender). A pre-tender qualification process ensured a trim tender pack of experienced steel contractors.

Prior to award of the contract, the Sub-Contractor, Central Welding Works, and their project team was interviewed about the project, complexities, ceiling support grid, and the tight programme.  The Engineer had prior significant experience of contracting work from Central Welding Works and this was a material condition of the award itself.

Close planning between the Engineers and Structural Steel Detailers, resulting in several important meetings, and then the presence of an impressive three-dimensional (3D) drawing back to the team (Employer, Architects, and Contractors), ensured a multilevel approval process, all done quickly due to a rapid and compact construction programme.

The team realized the complex and special requirements of the roof upfront and the need to get it right from all angles and stages, from start to finish.  The shaped vaulted acoustic roof and complicated ceiling elements are probably the most crucial part of a successful building and all aspects of this received priority attention from the whole team, including the Employer, Structural Steel Detailer, and Site Crews.

Tons of structural steel used  32 Tons
Structural profiles used All Sections
Cladding profile/ type used 0.58mm colored GRS Kliplok 700 concealed fix
Cladding area/ coverage and tonnage 1,120m²

Project Team

Project Team Role Company
Nominator KRU Detailing CC
Client/ Developer Rivonia Catholic Church

The Shopz Group

Architect AIB Architects
Structural Steel Detailer KRU Detailing CC
Structural Engineer Rouillard Consulting
Engineer Rouillard Consulting
Quantity Surveyor Norval Wenzel Steinberg
Project Manager Rouillard Consulting
Main Contractor Interbau
Steelwork Contractor Central Welding Works
Steel Erector Central Welding Works
Cladding Manufacturer Global Roofing Solutions
Cladding Supplier Tate & Nicholson
Cladding Contractor Tate & Nicholson
Corrosion Protection
Paintwork Contractor
Dram industrial painters

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.

RCL Foods Head Office, Westville

This project was undertaken in the framework of an extraordinary collaboration of the developer/landlord/contractor, tenant, architect, interior designer, branding alchemist and technical team. Somewhat of a ‘rescue operation’, we engaged by the developer to redesign a new corporate head office for RCL Foods after construction had commenced on the site in Westway Office Park. With a semi basement parking structure well underway for a generic commercial office block designed by another architect, the tenant decided that a bespoke design solution was imperative and the project entirely changed course. Key to advancing the conceptual approach for the workplace was an appreciation that the building was to be a pivotal part of creating a new culture for an amalgamated business of five individual corporate acquisitions. Driven by a desire to create Africa’s best and largest food company in the future, the directors of RCL Foods commenced weaving a non-corporate culture around the principles that people are the business and that the workplace environment should attract and retain the best human resource talent available. Working with the branding alchemist and the tenant engagement of our interior design company from the inception of the design proved to be an excellent decision as the stage was set for a fully integrated concept origination.


The new offices required to accommodate 700 people with an emphatic directive to create a bespoke environment exuding the culture of the business at every possible level. With growth and space planning flexibility demands being central to the physical programme, the need for a multiplicity of different meeting and collaborative spaces and a focus on food were imperatives. A desire for spatially connected workspaces with emphasis on providing a focal and legible public interface was expressed together with the need to create a variety of functionally usable external spaces.


The concept of the building delivers a significant linear atrium connecting all spaces and operations of the office building. This space is entirely given over to circulation, spatial connectivity and acts as the heart of the building. The application of steel, envisaged from inception, is expressly utilized in many primary and secondary components in the atrium space and is intended to be on show as the ‘theatrical’ material.



The functional and visual focus of the atrium is the cascading staircase which extends from the entrance area to the uppermost floor and connects all levels. This is created from a single 450mm diameter tubular section which almost impossibly spans up to 13m between bridges which connect the floors on either side of the atrium. This stair displays cantilevered treads and is carefully crafted to connect to the bridges comprising universal beams and other sections to produce visually light elements in the space.


Steel is deployed variously through the building internally to produce an architecturally dynamic environment. Its sometimes subtle presence, is almost unperceived and this amplifies its extraordinary role in this building as both a ‘star actor’ and ‘cameo parts’!  The extensive balustrading is a composite of delicate perforated steel plate and both steel and stainless steel sections. This delivers a lightness and transparency which is rarely evidenced in such components. The exposed lifts in yellow lift shafts exhibit the workings of a standard lift and this displays the importance of steel components in a lift. The flush glazed atrium enclosure is neatly supported in slender universal beam sections set unconventionally to accommodate blinds.


In an office which is unusual in nearly every way, all internal space divisions are unconventional.  Curvilinear glazed meeting pods, which precariously cantilever into the atrium, rely on curved steel tubular sections to support internal roofs and glazing, delivering a light and delicate support system. All internal meeting spaces and cellular office are created of freestanding steel framed structures where light tubular sections are deployed to support walls, glass and ceilings in many cases. Steelwork is seldom hidden and consistently treated in a dark charcoal colour, it demands both visual appreciation and indeed in its main roles, a ‘take your breath away’ awareness.


While RCL Foods is a fundamentally conventional wet-trades construction externally, many solutions to create the architectural outcome demand the use of steel. Hidden steel posts embedded in glazed enclosure, substructures for the signature perforated aluminium solar screens and giant tubular supports for impossible concrete cantilevers offer subtle and functional solutions through the building. Sporadic application of Corten is evident to selected and focal elements externally in the curved planters, gates and deck seating screens. This delivers a warm and crafted quality contrasting the cool grey and white exterior fabric.


This was a fast track project where the office building component was designed on a parking podium already under construction. So while the primary structure was being erected, decisions around methodologies to facilitate a near impossible completion date had to be made. Within the framework of a relatively conventional construction solution, the atrium usefully served as the concourse of construction. To allow efficient construction to proceed, the atrium roof demanded a soft roof using steel beams and lightweight sheeting as opposed to reinforced concrete. This decision, eliminating a forest of scaffolding then allowed the challenge of erecting a 70m long stair and series of connecting bridges to become manageable. Consistent and intense collaboration between Engineer, Architect, Interior Designer and Steel Fabricator became the hallmark of the design and construction process. Early involvement of the Contractor, Fabricator and Structural Engineer with significantly detail concept design at initial stages ultimately delivered a timeous and a remarkable outcome.

Tons of structural steel used      255 +

Structural profiles used Tubular and U.B.

Project Team

Project Team Role Company
Nominator EPA
Client/ Developer JT Ross
Architect EPA
Structural Engineer BPH Engineers
Engineer Not provided by nominator
Quantity Surveyor MLC Quantity Surveyors
Project Manager Not provided by nominator
Main Contractor JT Ross
Steelwork Contractor Rebcon Engineering
Steel Erector Rebcon Engineering
Cladding Manufacturer HB Interiors


Cladding Supplier HB Interiors
Cladding Contractor HB Interiors
Corrosion Protection
Not provided by nominator
Corrosion Protection
Paintwork Contractor
Not provided by nominator
Photographer, Photo competition Not provided by nominator
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.

PwC Tower – Triple Height Lobby

PwC Tower is PwC’s new head office in Johannesburg. The floor plates of the 28-storey building rotate by 1.2 degrees per floor, which results in a doubly-curved surface for the building’s façade and the structural line behind. The reception is housed in a triple volume lobby area at ground floor. This triple volume space flows into the adjacent meeting centre, and is used as a café and informal meeting space.

A steel and glass atrium roof covers the link between the tower and the meeting centre, whilst a steel link bridge with glazed balustrades connects the two floors at first floor level with a steel feature stair forming the principal link up to the second floor of the meeting centre. Whilst the majority of the tower floors are post-tensioned concrete, the first and second floors of the tower are formed in steelwork with bondek slabs and are hung from the third floor, to increase the column-free space in the lobby below. The northern part of the lobby features a triple volume steel and glass façade, gently following the twist of the tower. Within the atrium and outside the glass façade the sloping and spiralling columns of the building are encased in steel tubes to act compositely with the concrete inside; this increases the capacity of the reinforced concrete columns where they are unrestrained over the three floors and means that the overall section sizes can be similar to the rest of the tower which allows us to achieve the preferred architectural aesthetic. All of these components feature the use of steelwork in a complex geometric form and in the majority of cases the painted steel is exposed to form the finished surface.

Rectangular hollow sections were used on the skylight. The suspended floors were built out of BOND-DEK on cellular beams, with curved edge beams rolled horizontally. The hangers are circular hollow profiles. The bridge and stair are predominantly formed from welded plate with concealed connections and preformed slots for the cantilevered glazed balustrades. The façade mullions, spanning over three floors are I-sections, and are laterally restrained by circular hollow profiles. Rolled square hollow profiles are used over the main entrance doors. The structural columns in the tower are encased in large diameter circular hollow tubes.

The geometry of all this steelwork was generated by parametric scripts. The steel profiles were explicitly modelled in 3D by the design team. Conventional plans with all setting out information were produced for use on site but the 3D steelwork model was also issued to the contractor to use as the basis of their steel shop model and then later used to check the steel shop model.

Tons of structural steel used 250t
Structural profiles used RHS, CHS, UB, UC and plates

Project Team

Project Team Role Company
Nominator Arup
Client Attacq
Developer Atterbury
Architect LYT Architecture
Structural Engineer Arup
Quantity Surveyor Brian Heineberg & Associates
Main Contractor WBHO
Steelwork Contractor Cadcon
Steel Erector Cadcon
Cladding Manufacturer Geustyn & Horak (G&H Aluminium)
Cladding Supplier Geustyn & Horak (G&H Aluminium)
Cladding Contractor Geustyn & Horak (G&H Aluminium)

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.

Gateway West, Waterfall Kyalami

This is a landmark project, albeit small in tonnage terms. It illustrates what can be achieved using LSF!

The bi-axially curved façade walls give expression to the architect’s design, at a much lower cost than would have been the case had reinforced concrete been used. The rapid assembly and erection shaved weeks off the building programme. It provides a ventilated façade which translates into thermal insulation to the office building interior. The wall panels consist of (from the outside) aluminium cladding (thickness?), ETICS cladding (60 mm thick), vapour permeable membrane (?), 90mm LSF support structure, Cavity Bat insulation (?), Fire Stop gypsum board. Key for the success of the project was the meticulous 3-D design to facilitate integration of the curved LSF framework, the window schedules and the structural concrete.

What makes this project special? LSF allowed the designer to create a unique and striking building exterior, like no other. The insulated LSF walling provides excellent insulation (R-value …..) which will save electricity for heating and cooling over the design life of the building. It was executed at much lower cost than alternatives, and is said to be maintenance free. It is a prominent reminder on the Waterfall skyline of creative designs. A comment received from the USA sums it up – ‘in what galaxy is this building?’

Tons of LSF used 7 ton
Profiles used 90mm C section
Cladding profile/ type used Weber ETICS and 15mm Firestop Gyproc boards
Cladding area/ coverage and tonnage 1400 sqm

Project Team

Project Team Role Company
Nominator Ohlhorst LBS Pty Ltd
Client/ Developer Attacq Property Development
Structural Engineer HAGE engineers
Main Contractor Group 5
Steelwork Contractor Ohlhorst LBS Pty Ltd
Steel Erector Ohlhorst LBS Pty Ltd


Cladding Supplier Quinton
Cladding Contractor Ohlhorst LBS Pty Ltd
Photographer, Photo


Ohlhorst LBS Pty Ltd