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Embracing

Composites

The Barak Building, Swanston Square, Photo by Peter Bennetts.

WORDS BY Toby Whitfield

Composite construction is one of the oldest methods of building known to man. The craft of weaving fibre to create strength goes back thousands of years – the original mud hut is the first example of composite building, straw or sticks woven together and held in place by mud. Today we use a range of natural and engineered fibres in place of straw, and the mud has been replaced by a range of resin systems all with a huge variety of mechanical attributes.

Of course our manufacturing needs have changed as well. No longer is it the simplicity of the mud hut. Rather, today’s architectural designs call for innovative solutions to meet the demands of increasingly complex form and structure. The latest developments in the world of advanced composites mean almost any shape you can imagine can be manufactured as lightweight structures – with the required rigidity and strength to allow extraordinary architectural design.

So what exactly are “advanced composites”? In general terms advanced composites are not widely understood. Terms such as GRP (Glass Reinforced Polymer) or FRP (Fibre Reinforced Polymer) give a misleading impression of consistency and uniformity. It is reasonable to use these generic terms to describe and group low quality, mass-produced parts such as truck bonnets or swimming pools. However, it is dangerous if you don’t recognise the huge difference between such mass produced parts and the highly engineered, structural facades that are adorning more and more high profile buildings, 30 stories up. While mild steel and titanium could both be described as “metal”, the performance characteristics are profoundly different. The same range applies in composite manufacturing.

The preconception of composites as used only for “cheap” products simply reflects a lack of understanding. The reality is advanced composites should be seen for what they are – a 21st Century structural textile. A smart, sophisticated response to a design challenge.

Every input has an impact

The composite engineer responding to the unique design challenge has a number of variables at their disposal, each of these inputs has an impact on performance.

1. What kind of fiber reinforcement?

• High quality woven directional fibre or chop strand mat?

• Glass fibre, natural fibre or is there a more specific challenge perhaps requiring Kevlar (impact resistance) or Carbon fibre

• Quantity (thickness) of the fibre reinforcement.

• Orientation of the fibre (this will typically be designed to change from one layer to the next).

 

2. What manufacturing method?

A low-tech manufacturing technique can only every deliver an inconsistent product. Variations in resin to reinforcement ratio has a large impact on strength, weight and fire retardant qualities.

• Chopper gun – low quality non-structural (truck bonnets, swimming pools).

• Wet layup (hand consolidation) – prone to inconsistency due to high individual influence.

• Vacuum infused – high quality, consistent result with predictable resin ratio.

• Pre-impregnated cloth cured with pressure and heat (autoclave) – Aerospace quality.

 

3. What resin system (binder).

• Polyester

• Vinyl ester

• Epoxy

• Fire retardant systems

Each one of these choices has a large and inter-dependent impact on the end result.

The growth of advanced composites in such diverse industries such as construction, defence, infrastructure and aerospace gives some indication as to how empowering composites can be to the design process. As more and more industries embrace the benefits of composites, the price of the inputs are dropping and the skill level in manufacturing is increasing.

And while it is possible to create complex forms in concrete and steel, they are often either prohibitively expensive or incredibly difficult to achieve, or both. So, when considerations of the cost of installation, overall environmental footprint and compliance when compared to other systems (steel, concrete etc) then this new technology is due to play an integral role in architectural design and building construction for decades to come.

 

Images courtesy of MouldCAM.

Images courtesy of MouldCAM.

 

Images courtesy of MouldCAM.

Images courtesy of MouldCAM.

William Barak Building, Swanston Square, Photos by Peter Bennetts.

Design technology in composites and the role of collaboration

The world of advanced composites is not a one-size-fits-all proposition. Rather, it allows for a high level of collaboration between architect and the design technology team. Through this process the best possible solution is developed to not only achieve the design intent, but also the critical dimensions of cost and buildability; so important if the intent is going to be maintained through the dreaded ‘value management’ phase. Technological expertise and ongoing research and development create customised solutions. These not only meet the creative demands of the architect, but also allow for a playful use of materiality.

A perfect example is a new precast structural substrate of woven reinforcement with an exterior of the highest quality Australian Barossa quartz, granite, sand and cement. By introducing a specific binder compatible with both the cement, stone and the fibre reinforcement the result is not an imitation, but a modern reincarnation of one of our most specified building materials.

Dubbed ‘ShapeShell Precast Light’, this advanced composite has the beauty and texture of natural stone but at approximately 5% of the weight. Acoustic and thermal cores can be added to the panel to deliver all of the key elements without the extra consumption of raw materials and added weight. Advanced weather testing to prove no changes in surface finish and the highest level of fire certification means there is little excuse left to be specifying resource hungry inefficient and heavy products.

Architects and engineers are now confidently ‘designing in’ these weight savings from the very beginning, thus leveraging the benefit of the material throughout the project. Core structure and slabs can be proportionately lightened, build times can be reduced as more work can be done off site. It is simply a more responsible design response. If 5mm of a quartz, granite and cement mix delivers the look and textural response, why back it up with 95mm of cement when you could have 10mm of woven structural fibre and a specifically designed acoustic and thermal insulating core? Save the resources, stop the hundreds of trucks to site, and perhaps reallocate these funds to design aspects that are tangible to those who will be utilising the space.

In Australia it is the architects who embrace innovation who are reaping the rewards of this collaboration. A recent example is the Barak Façade by ARM Architecture (Ashton Raggatt McDougall) where no less than 411 double curved unique panels were manufactured to create the 3D portrait of Aboriginal elder William Barak as he gazes down one of the main streets of the city of Melbourne, Australia.

Installed over 35 floors, no two panels are the same, thus adding to the creativity and complexity of the project. Importantly the ShapeShell freeform ‘monocoque’ panels needed to have depth (thickness), be solid in construction (no hollow drum sound) yet lightweight and structurally stiff to allow minimal fixing only at slab edge. The solution was to create monocoque panels with structural skins to carry the load across all sides of the panel. The panels were independently tested and taken up to a load of 6.4 Kpa without any signs of damage (cosmetic or structural) nor residual deformation. The strength of the panels allowed slab edge fixing despite a considerable vertical cantilever of up to 2.5 metres.

Fearless Design

To provide architects, designers and artists with the confidence to use advanced composites, companies like ShapeShift Design Technologies are changing the landscape. Through the creation of a range of advanced composite products under the brand ‘ShapeShell’, ShapeShift Design Technologies ensure these products are not only tested to the highest Australian Standards but they are manufactured using the latest technology and highest quality materials to provide consistency and uniformity.

Through the product line ‘ShapeShell’, artists, architects and designers can access this sophisticated build medium without the risk. ShapeShell draws on the best aspects of composite manufacturing but has added to it dimensions fundamental to an architectural practice such as a range of material inputs (eg stone & cement), fire proofing, structural certification, surface finishes guaranteed for 25 years, as well as high quality manufacturing, and Australian standards testing and certification.

A new and very powerful tool has been added to the tool kit. Resistance to change is always the biggest hurdle, but for those who recognize that good design is about a responsible use of appropriate materials, they will enjoy the liberation from heavy, unsophisticated materials and the huge potential at their disposal.

www.ShapeShift.tech

www.ShapeShell.com.au

Image courtesy of MouldCAM.

Image courtesy of MouldCAM.

Image courtesy of MouldCAM.

1. MPavilion – AL_A – London

The MPavilion in Melbourne is a project where the cross-pollination of ideas across multiple industries – from the reinforced carbon fibre tripod stems, to the lightweight yet rigid petals – has created a stunning outcome. It is made from 60% renewable soy products. The ultra thin 4-metre high stems on which the petals sit were designed to move in the wind, the design coming from the high tech tripods for cameras. The pre-tensioned carbon fibre strands provide stiffness for the 3mm thin petals over 5 metre spans. A bespoke weaving loom was designed as part of the full production process design.

2. Victorian Comprehensive Cancer Centre –STHDI+ McBride Charles Ryan

The light weight nature of composite construction allows for greater spans than ever before – up to 12 metres in the case of the VCCC façade. The organic design of the perimeter colonnade was made possible through stretching every aspect of 3D design, CNC cutting technology and advanced composite manufacture.

3. Spanda – Christian Di Vietri – Elizabeth Quays, Perth

The Spanda art installation in Perth is a perfect example of using different materials in combination to deliver a total solution. The lower sections are a fibre composite wall filled with cement. These sections are integrated into the primary foundation slab. As the sculpture reaches its full height of 30m while also tapering, carbon fiber was introduced into the laminate to achieve the required stiffness.