LSAA 2018 Design Awards AWARD OF EXCELLENCE - Category 7 Special Applications (7235)
APPLICATION OF PROJECT:7235)
Application: Custom Lightweight Architectural Structure with aluminium cladding
As part of the Westfield Chermside AUD$355 million redevelopment, we were contracted for the fabrication and construction of a large scale custom aluminium retail structure, and subsequently, a porte cochère entry structure. The aluminium structure is called the ‘Urchin’ as the distinctive shape resembles the round, jagged edges of a sea urchin. The design intent behind the structure was to create a main focal area for the redevelopment and a “meeting point” for the centre. The area below the Urchin is used for events and entertainment, thanks to its amazing programable LED lighting system integration. The Urchin is our first large architectural structure that does not include any fabric.
Images Copyright Steve Ryan, Rix Ryan Photography
Westfield Chermside received an AUD$355million redevelopment, finishing in 2017, that would create an extra 33,000m2 of retail space and become home to just under 100 new stores. The centre caters to a population of over 780,000 consumers which is approximately 32% of the population of Brisbane. Some of Australia’s best known retailers are at Chermside, including Myer, David Jones, Gib W, Coles, Woolworths, Apple and Target.
DESIGN / FABRICATION / INSTALLATION BRIEF
The Westfield Chermside Urchin project is a large, iconic architectural structure situated in middle of the alfresco dining area of the centre. The structure was originally named the ‘bird cage’ due to its arching shape but was renamed to the ‘urchin’ after the design changed to include a series of aluminium cladding panels. The outline of the structure appears spikey due to the jutting corners of the structure. The Urchin was designed to provide shade for the lower levels while also standing as a sculpture/landmark for the shopping centre.
Each layer of cladding has a different geometry as it moves up towards the peak of the structure. There is a different folding pattern which makes the structure extremely dynamic. The open spaces between each panel create a captivating ambience beneath the structure that changes as the sun moves throughout the day.
The lower steel ring beam was custom folded plate running in two different curvatures. The primary steelwork of the structure was very architectural, spiralling around with double-curvature as it works its way up towards the top. The secondary steel was designed to accompany and hide the lighting system, as well as connect the panels. The integrated LED lighting has been incorporated around the steel that reflects magnificently off the white panels at night. The lights can be programmed in a variety of different colours, patterns and speeds to suit any occasion.
The structure had to be designed to be lightweight as its weight and loads were very limited be the capacity of the thin tensioned-concrete-slab where the structure connects to.
Additionally, it was quite a challenge to design the secondary steel to accommodate about 3,000 cleats for the 677 aluminium panels and conceal all the electrical reticulation and LED lights.
The PVDF coated aluminium panels were chosen not only because they were a lightweight option that suited the installation requirements, but also because their unique patterning, grooves, and shapes could create the design shape required.
The 5,005 aluminium cladding panels are from a specialist fabricator. They are 3mm, 4mm, and 5mm thick with a PVDF paint system on both sides of the cladding.
Every single panel was modelled, flattened, and fabricated using CNC equipment to achieve the design geometry with millimetric accuracy.
COLLABORATION, CONSTRUCTION AND MAINTENANCE
There was a specific requirement in the way the Urchin structure was connected to the second story slab and the supports below. There is a car park underneath with columns coming up, so the base of the structure had to land on the columns. As you can imagine, this meant there was a lot of coordination involved with this.
The ring beam geometry was designed around these joints, which meant lots of coordination with the client and their consultants as well.
Role played by Entrant: Designer / installer
Location: Chermside, QLD
Completed: November 2016
Client: Scentre Group Design
Architect: Armada Architecture; Urbis Design
Engineer: Fabritecture; Wade Design Engineers
Builder: Scentre Group Design
Photo Credits: Steve Ryan, Rix Ryan Photography
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