Civil Engineering March 2021 | Vol 29 No 2

WINNER IN THE COMMERCIAL CATEGORY New Barloworld and Caterpillar head office and showroom The new Barloworld and Caterpillar head office and showroom in Isando was conceptualised as a series of iconic build- ings nestled in an indigenous landscape. The development consists of a head office, training campus, and a world-class showroom facing the R24 highway for maximum exposure. Building features The head office, comprising two elongated buildings, is linked by an enclosed glazed bridge whose design encompasses flush- glazed strip windows. The prevalence of glass in both buildings ensures maximum sunlight because of their north-facing orientation, minimising the need for artificial heating and lighting. 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, coupled with a vast glass façade. The building claims a never-been- done-before international breakthrough with a staggering 8.8 m × 5.5 m piece of the prominent glass frontage being fully retractable via intricate motor-driven automation to allow large equipment to easily enter or be extracted from the space. The desired design would have not been possible without the use of steel. Building with steel The two ends of the building consist of curved structural steel horizontal sheeting that cantilevers out about 15 m from the base and is about 15 m tall. This presented an engineering challenge to keep the deflections within allowable limits while also keeping the structural elements economical and within the allowed sizing envelope. Stressed cables were therefore used 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, 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. The two end barrels of the building imposed significant horizontal forces onto the roof that needed to be catered for, and brace bays were used to take these loads back to the foundations. The result is a flagship Caterpillar showroom that caters for equipment usually too big to be accommodated indoors except in barnlike servicing warehouses. KEY PLAYERS Client/Developer Eris Property Group Architect Paragon Architects Structural engineer DG Consulting Engineers Main contractor Trencon Construction Steelwork contractor/ erector Central Welding Works Cladding manufacturer/supplier Global Roofing Solutions Cladding contractor Chartwell Roofing 46 March 2021 Civil Engineering