The new Barloworld and Caterpillar head office and showroom in Isando. is dedicated to heavy earthmoving equipment. The development consists of a head office, world-class showroom and new training campus.The showroom alone is a first-of-a-kind in the country and is split into two zones, namely “tyre” and “track” product categories, with both open and enclosed areas. Emmy Leeka, CEO of Barloworld Equipment, said the project was conceptualised as a series of iconic buildings nestled in an indigenous landscape, with the showroom facing the R24 highway for maximum exposure.   Features of the new buildingThe head office, comprising two elongated buildings, are linked by an enclosed glazed bridge.Its design encompasses flush-glazed strip windows. The prevalence of glass in both buildings ensures maximum sunlight because of their north-facing orientation. This minimises the need for artificial heating and lighting.Both the head office and showroom roof structures were designed to cater for photovoltaic panels.The most immediately noticeable feature of the new showroom structure is its elongated front-facing bubble profile, inspired by the curved shape of the Caterpillar excavator tread. Not only is this an iconic visual tribute to the legendary earthmoving equipment showcased within, but it also allows this huge machinery to be comfortably exhibited in the voluminous interior space this design creates. Couple this with a vast glass façade, which makes the interior exhibit perfect visibility of the busy R24 highway, and this becomes far more than a cutting-edge combination of corporate head office and flagship showroom. How can such huge apparatus easily enter or be extracted from this space? The building claims a never-been-done-before international breakthrough with a staggering 8.8m x 5.5m piece of the prominent glass frontage being fully retractable via intricate motor-driven automation. The architectural briefFittingly, Barloworld Equipment’s impressive new head office and Caterpillar equipment showroom in Isando breaks new ground. It was a monumental brief – Barloworld Equipment, dealer for iconic Caterpillar earthmoving equipment, was leaving Sandton and wanted a state-of-the art head office on the R24 at Isando that reflected their corporate identity and accommodated staff in comfort. But beyond that, they wanted the development to include a flagship Caterpillar showroom for their equipment – excavators loaders, dozers and graders that build the nation’s roads, dams, harbours and airports, and are usually too big to accommodate indoors except in barnlike servicing warehouses out of the spotlight. ‘This is the first showroom in the country dedicated to heavy earthmoving equipment,’ says Aashen Lalloo, development manager at Eris Property Group. ‘The brief to Paragon Architects was to balance iconic design with functional aesthetics while maintaining a cost-effective solution.’ Paragon, of course, were up for the challenge – the design power behind some of the most advanced buildings in the country, they relish pushing the envelope architecturally and technically, reaping awards with the likes of Sasol Place, Alice Lane and 140 West. Their approach to Barloworld Equipment was both simple and singular. ‘Who hasn’t played with toy earthmovers as a kid?’ says David Cloete, the architectural technician Project Leader for the project. ‘We wanted to hero the equipment, and it may sound corny, but some of the best ideas came when we bought a set and played with them while brainstorming.’ They began with what has become a Paragon signature: the two-tower building linked by an atrium and brought it down to earth to conform to the height restrictions of a site close to OR Tambo International. The result was two long, low structures – one three storeys, for the showroom, the other two storeys, for offices. Then taking inspiration from the circular tracks of a classic Caterpillar earthmover, they turned them into what Cloete calls ‘two bubble shapes’ – striking, glass-walled edifices, floating on a low podium above a semi-basement parking level, and linked by an enclosed glazed glass bridge, covering 4500m² all told. The 3200m² showroom bubble was built to face directly on the busy R24 – creating the ultimate traffic stopper, commanding immediate attention with its striking shape and the machinery that inspired it displayed inside in two sections, one for track Caterpillars, the other for those with tyres. Beyond this, just that glass corridor away, lie the company headquarters: two floors of flexible open-plan office space with sophisticated floor-to- ceiling flush-glazed windows. It was an ingenious solution, but hard won. The challenges began with the very earth the structures stand on, which is the clay variety and notoriously unsteady, especially after torrential Gauteng rains. ‘Not ideal for building foundations,’ as Cloete says. ‘For a high-rise like most of our projects, you need to dig deep, but because we were only going up three story’s, we dug just three meters below the surface and laid man-made sub-surface to compact the soil beneath a raft foundation. It needed to support all that Caterpillar equipment, and the biggest pieces weigh up to 60 tons.’ Next challenge was the dimensions of the showroom, and how to move the equipment in and out. ‘It requires massive clearance in height as well as width to turn one of these mammoths.’ Paragon took for its starting point the roller shutters used to access the Caterpillar servicing warehouses. ‘But we wanted to use glass, not metal.’ So in what they believe is a world first, they elected to vertically slide a 8.4m by 5.5m section of the high-performance glass frontage upwards, using a complex motor system installed upstairs and hung from a structural beam. The challenges did not end there. Architecturally, the only straight feature in the bubble structures is their glass frontage, and Paragon needed to achieve curved roofs and sides that sealed with the straight lines to make the structures weatherproof and insulate them thermally. Here again, the solution was deceptively simple: ‘Good old corrugated iron,’ says Cloete with satisfaction. ‘I love its connotations of industry and farms, where Caterpillar has its roots with its creation of factories and dams. It worked spectacularly and helped bring in the project on budget.’ A steel girder framework was created to provide for the track-shaped design of each of the two bubbles, with large spanning trusses that carry the roofs, all sitting on a specially devised grid (‘increased to 12m or 15m,’ says Cloete) to accommodate the different-sized equipment required. Then the corrugated iron was applied like an external skin.  Throughout it all, Paragon worked closely with Trencon Construction, the main contractor. ‘We operated as a team, which was of paramount importance given with the intricacies of design combining the use of glass and steel,’ says Trencon contracts manager Ernst Bezuidenhout. The steel structure was difficult both to manufacture and erect, and they used tension cables in the roof structure to help with installation of the glass and adjust the fit of the façade panels. Although the developers were not targeting a green-star rating, Paragon practices ensure all their projects would qualify for at least three green stars, Cloete says. ‘So, we oriented the two buildings to face north to ensure maximum sunlight and minimize the need for artificial lighting and heating. And we designed the roof structures to cater for photovoltaic panels for solar power, to feed the electrical requirements for the offices.’ The flush-glazed unitized glass façades feature performance glass, and the canopy formed over these by the roofing have a sizeable 3.5m cantilever (another Paragon signature), that provides shading in summer while being exposed in winter, heating the interiors naturally. Sustainable Building FeaturesThe Barloworld Equipment head office building and showroom incorporate green elements in line with Paragon’s practices: They were positioned to face north to reduce energy requirements.The roof structures for both bubbles were designed to cater for photovoltaic panels.The canopy of the top edge of the bubble design facade has a 3.5m cantilever to give substantial shading in summer, but the façade is exposed in winter to heat the internal space naturally.Low-rated sanitary fittings were specified throughout for minimal water consumption.Was the project envisaged in steel from the start?Yes, in short this would have not been possible to achieve the desired design without the use of steel as explained below. The project was envisaged to be steelwork from the start, but not all elements: The steel fascia trim along the length of the building was investigated to make use of a different material, however structural steelwork proved to be the only material that proved flexible enough to form the required shape.The roof structures to cater for photovoltaic panels for solar power, to feed the electrical requirements for the offices.’ The flush-glazed unitized glass façades feature performance glass, and the canopy formed over these by the roofing have a sizeable 3.5m cantilever .The two ends of the building consist of curved structural steel horizontal sheeting that both cantilevers out about 15m from the base and is about 15m tall. This presented an engineering challenge to keep the deflections within allowable limits whilst also keeping the structural elements economical and within the allowed sizing envelope, especially since the large cantilever bow also carried a flush glazed façade which has very stringent allowable deflections. We made use of stressed cables to hang the bowing cantilever arches from the remainder of the roof. To control and monitor deflections and to ensure the safe erection of the structure we issued the contractor with specific installation methodologies and sequences to follow. The cables needed to be stressed in two sequences at certain times during the erection process to ensure that they did not over-stress the structure which did not yet carry all the building’s self-weight. We also requested that the cables were kept open for final adjustment if required up to the very end of the project before having them trimmed and instructed the contractor to take accurate surveys of the structural steel positions as it was being erected and finalized. These two end barrels of the building imposed significant horizontal forces onto the roof that needed to be catered for. We made use of brace bays to take these loads back to the foundations however there was no opportunity for any bracing to the front of the building since it was to be a fully retractable glass façade. Instead we pulled the one vertical brace to the floor back to the nearest acceptable position which was beyond the centroid of the barrel load which whilst still feasible increased the loads onto the bracing system significantly. Curved plate girder channels and compound curve RHS sections made from plate were difficult to fabricate and install while maintaining the fixed glass support line on site. Impressive Technical Aspects of this projectThe building curves in 2 planes - These two end barrels of the building imposed significant horizontal forces onto the roof that needed to be catered for. The head office, comprising two elongated buildings, are linked by an enclosed glazed bridge.Its design encompasses flush-glazed strip windows. The prevalence of glass in both buildings ensures maximum sunlight because of their north-facing orientation. This minimises the need for artificial heating and lighting.Both the head office and showroom roof structures were designed to cater for photovoltaic panels.The most immediate noticeable feature of the new showroom structure is its elongated front-facing bubble profile, inspired by the curved shape of the Caterpillar excavator tread. Not only is this an iconic visual tribute to the legendary earthmoving equipment showcased within, but it also allows this huge machinery to be comfortably exhibited in the voluminous interior space this design creates.What is special/ unusual/ innovative/ aesthetic about the steelwork in this project? The two ends of the building consist of curved structural steel horizontal sheeting hat both cantilevers out about 15m from the base and is about 15m tall. This presented an engineering challenge to keep the deflections within allowable limits whilst also keeping the structural elements economical and within the allowed sizing envelope, especially since the large cantilever bow also carried a flush glazed façade which has very stringent allowable deflections. We made use of stressed cables to hang the bowing cantilever arches from the remainder of the roof.To control and monitor deflections and to ensure the safe erection of the structure we issued the contractor with specific installation methodologies and sequences to follow. The cables needed to be stressed in two sequences at certain times during the erection process to ensure that they did not over-stress the structure which did not yet carry all the building’s self-weight. We also requested that the cables were kept open for final adjustment if required up to the very end of the project before having them trimmed and instructed the contractor to take accurate surveys of the structural steel positions as it was being erected and finalized. These two end barrels of the building imposed significant horizontal forces onto the roof that needed to be catered for. We made use of brace bays to take these loads back to the foundations however there was no opportunity for any bracing to the front of the building since it was to be a fully retractable glass façade. Instead we pulled the one vertical brace to the floor back to the nearest acceptable position which was beyond the centroid of the barrel load which whilst still feasible increased the loads onto the bracing system significantly.  Project motivation editorials are provided by the project nominator. If any technical details, company names or product names are incorrect, please notify the SAISC so that the error can be corrected. PROJECT OVERVIEW Physical address of the project Street Address Town Province Electron Avenue Ext, Isando, 1600 Google Maps link https://goo.gl/maps/DYb8LbbVDTNTUA8t8 STRUCTURAL STEELWORK Completion date of steelwork August 2019 Completion date of full project December 2019 Tonnage and steel profiles used Plate girder channels and curved beams + normal HR sections 220 tonnes   CLADDING (If applicable)  Completion date of cladding  September 2019  Cladding profile/ type used  Corrugated 10½ & Klip-Tite  Cladding area coverage   ± 11 165m²  Both cantilevers out about 15m from the base and is about 15m tall Cladding tonnage  Klip-Tite = 34 537 Ton & Corrugated = 48 279 Ton  Nominator Central Welding Works Nominator Global Roofing Solutions Client/ Developer Eris Property Group Architect Paragon Architects Structural Engineer DG Consulting Engineers Engineer DG Consulting Engineers Quantity Surveyor Matla Quantity Surveyors  Project Manager SIP Project Managers Main Contractor Trencon Construction (Pty) Ltd Steelwork Contractor Central Welding Works Steel Erector Central Welding Works Cladding Manufacturer Global Roofing Solutions Cladding Supplier Global Roofing Solutions Cladding Contractor Chartwell Roofing (Pty) Ltd. Paintwork Contractor Dram Industrial Painters Paintwork Contractor First Class Projects CC  Structural Steel Detailer KRU Detailing Nomination Document Submission KRU Detailing 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.