The expansion of Chadstone Shopping Centre in Melbourne, Australia, is a seamless celebration of engineering and architecture. CallisonRTKL served as Designer and The Buchan Group as Architect on the project, which has been a staple of both practices’ portfolios since the 1980s. The project’s centerpiece is a dramatic gridshell glass roof, which soars above what has become the largest and most popular enclosed shopping centre in the Southern Hemisphere. The expansion accommodates upwards of 100 new retailers and a roster of leisure and food operators. The 31-meter high, 7,000-square meter roof was a multi-disciplinary collaboration of designers, architects and engineers working with research departments from the University of Stuttgart and the University of Bath. The design team relied on 3D parametric modelling, refining the massing through a combination of video animation and computer rendering. The roof is the first of its kind on the continent.
Almost touching the sky at Chadstone‘The Fashion Capital’ The self-supporting, curving glass roof in Melbourne was con-structed using GEWE-therm®sun 4SG thermal insulation glaz-ing. International Architects: Callison RTKL UK-Ltd based in London in collaboration with Melbourne Architect: The Buchan Group, Atelier One structure engineers and façade specialist seele have created a breath-taking free-form grid shell structure constructed from steel and glass at the Chadstone ‘The Fashion Capital’ in Melbourne,Australia. The gently curving roof appears to rest on the building like a delicate shawl. In reality the construction’s domed and vaulted steel elements, which arch over the two-storey passages of what the operators call “Australia’s pre-eminent shopping destination and the nation‘s number one shopping destination”,weigh 500 tonnes.
Every element is unique Some 2 670 panes of SCHOLLGLAS GEWE-therm 4SG insulated glass equipped with external sun protection regulate the amount of natural light entering the building;its heat insulation and protection against the sun. Every pane has a different shape and dimensions – no two trapezoidal or triangular panes are the same, not even in terms of their surface shape. The panes, ranging from 1.2 to just under 8 square metres in size, have all been modified to fit the curving construction de-sign. To create it, the experienced façade construction team used an on-site bending procedure to install the glass elements, initially manufactured as flat units, into the curved pro-files, thus ensuring that the “cold bent” glass took on exactly the spherical geometry required for each frame. This was pos-sible because, despite the overall roof construction’s expressive wave shape, each individual pane has only a minimal curve. Such a construction method is already a challenge when using single glazed elements – in this case two-layer insulated glass from SCHOLLGLAS, consisting of one pane of toughened safety glass and one layer of laminated safety glass made from two panes of annealed glass, had to be bent.
In combination with the argon-filled interspace the units were approximately 39 millimetresthick and were adjusted to match the curvature of the supporting construction during installation. 4SG optimizes function and design For its GEWE therm sun protection and thermal insulation glass SCHOLLGLAS used 4SG edging with a thermoplastic spacer specially developed for structural glazing façades. The flexible but almost stresslessly formable spacer allows a water vapour-impermeable, gas-tight edging seal which ensures both physical and chemical adhesion and thus an optimum connection between the glass and the silicone secondary sealing. In combination with the 4SG spacer this delivers edges which are permanently sealed and ‘warm’ in energy terms, particularly in the case of applications involving highly challenging pane geometry or where glass is expected to distort.
Precisely planned delivery and assembly The project’s logistics also presented the companies involved with major challenges. After completion, each construction phase was glazed in stages – based on a precisely planned manufacturing and delivery chain. The window panes, manu-factured in Germany in special shapes and dimensions, were shipped by container to Australia. When doing so, they were packed extremely carefully in solid-wood seaworthy containers using individual pane protection and ShockWatch devices.
The expressive, distinctive glass design is a highlight of the ChadstoneThe Fashion Capital, not only in terms of urban planning and architecture. In addition to this, the heat insulat-ing roof glazing in combination with a large volume of natural light inside the building but also protection against overheat-ing, also delivers impressive ecological added value. Green-house gas emissions have been reduced by 61 percentover other shopping malls. This has been rewarded, among other things, with a 5-star sustainability rating from the Green Build-ing Council of Australia.