Beyond their important functional requirements, some of the qualities exhibited in this selection of structural elements suitable for commercial applications include their ability to help reduce environmental footprints and their capacity to contribute to aesthetic outcomes.
In an age where architectural success is measured in terms of not function and form, but also closely watched bottom lines, heightened environmental awareness and more, structural elements continue to evolve.
Columns & curves
According to AFS Systems, a leading player in the permanent formwork industry, one of the most interesting recent developments in in this area is the increased popularity of columns and curves.
While in the case of curves, the trend is very much design-driven, blade columns are important because they’re all about useable space. For architects and designers, the attraction of slimer load bearing blade columns comes down to the fact that they deliver more useable space, while for builders the attraction is more about speed. They allow them to complete their work faster.
The company has introduced the RW200 curved system, an easy to install solution that comes in a 0.5M radius (1M diameter) with 15-degree angles. Finished in standard Rediwall white PVC, it meets all required performance standards – including those relating to fire, acoustic and thermal capabilities.
Then, in terms of columns, AFS Systems offers an advanced design method to construct AFS Rediwall blade column and wall. With simplified design and detailing, it provides flexibility in combining walls, columns, blades, and cores. It can ensure increased speed of installation by reducing the complexity of confinement ties with the use of U-bar reinforcement arrangements. while meeting the compliance requirements of AS3600-2018 Amendment 2 and the NCC.
Tried & tested solutions
According to Peter Robertson, Director of Robertson Façade Systems, concern regarding the much-publicised presence of combustible external cladding on multi-storey buildings has led many architects, engineers, and developers to return to “tried and tested solutions”, like brick and concrete.
“We supply a system to embed thin brick into precast concrete. Naturally designers are looking for flexibility and interesting design challenges. With this support we have created new brick bond patterns, protruding brick options and curved panel solutions,” says Robertson.
Known as Brick Inlay, the system was developed in the US by a company called Scott System. One of the best examples of its use is at the San Francisco Museum of Modern Art, a project by renowned Swiss architect Mario Botta.
“The challenge [on that project] was to have a brick façade that related to the San Francisco character and have this perform safely with the seismic challenges presented by the San Andreas fault,” Robertson says.
Having been made a licensee of the system in 1998, Robertson Façade Systems has gone on to supply it for numerous projects in this part of the world.
One noteworthy recent example is Auckland’s Hotel Britomart. As in the San Francisco Museum of Modern Art example, one of the main considerations in this project was ensuring the brick inlay met New Zealand’s stringent seismic requirements. After six months of compliance testing, which included the production of a series of mock-up brick panels, this was achieved, and the system was deemed suitable to use.
Considering the result, a slimline grey brick tile blend paired with glazed, frameless tessellated windows, this level of thoroughness was clearly worth the effort. Today, the Hotel Britomart stands as not just the first building in New Zealand to feature a façade of this type, but also a welcome addition to the heritage precinct in which it stands.
Image: Auckland’s Hotel Britomart / Robertson Façade Systems
The emergence of structural timber
Another development worth noting is the rapidly growing interest in structural timber.
“In the last couple of years, we’ve seen an amazing variety of buildings incorporating structural timber elements delivered around the country,” says Laurence Ritchie, an Advisor with Woodsolutions, a not-for-profit information provider, resourced by Forest & Wood Products Australia and supported by industry bodies and technical associations.
“From aquatic centres, to libraries, schools, apartment buildings, offices, and more, actual experience has demonstrated that structural timber products can be utilised to deliver diverse indoor and outdoor spaces.”
According to Ritchie, this boom in the use of engineered wood products (EWPs) in commercial projects has been driven by two key factors – increased interest in sustainable outcomes and the updating of building codes around the world to consider and allow mid to high rise timber systems as a standard construction method.
“Interestingly we’re just starting to see EWPs take off in popularity in mid-high-rise offices, with glue laminated timber (Glulam) and cross laminated timber (CLT) being specified in a few major office projects in Melbourne and Sydney,” says Ritchie.
As he explains, Glulam and CLT along with another type of EWP known as laminated veneer lumber (LVL), can be produced in large-format columns, beams, and panels. Lighter, easier to connect, more aesthetic, and better for the environment than familiar precast elements, these products can be used for the same purposes as precast concrete – as columns, beams, suspended floors, loadbearing walls, etc.
“The use of these products offers a range of benefits to a project beyond the obvious sustainability outcomes. They typically weigh about 80% less than a reinforced concrete alternative so they are fast to lift and easier to install. They’re very dimensionally stable meaning they don’t require ugly expansion joints,” says Ritchie.
And, beyond their acknowledged capacity to “imbue a really beautiful raw yet comfortable aesthetic to an indoor space”, they don’t conduct heat well, and can therefore help create very thermally stable indoor environments.
CLT installed alongside steel & concrete
According to Kieran Hayes, Senior Technical Engineer at XLAM, a leading Australian producer of CLT and manufacturer of panels ranging in depth from 90mm to 310mm, CLT is being installed also alongside steel and concrete in a hybrid building typology for buildings of all sizes.
“We are now often seeing CLT paired with alternative beam elements from the traditional combination Glulam,” said Hayes.
XLAM recently introduced the first ever CLT band beam solution.
CLT Band beams follow the same principle of manufacture as CLT panels. Layers of radiata pine boards are stacked together in alternating directions and bonded by adhesive. However, these beams are manufactured up to 360mm deep and typically range from 900mm to 1700mm wide.
“These band beams are used in place of primary Glulam, steel or concrete and can be paired with CLT slabs that run over the top. The CLT slabs can be connected to the beams using inclined screws or adhesive to develop composite action,” said Hayes.
The product was developed in response to two main drivers. The first relates to the fact that, traditionally in Australia, construction of mid-rise buildings has involved the use of PT concrete band beams. These systems have shallow structural depths which allow services to reticulate beneath beams and means there is very little need for coordination between engineering disciplines.
“The CLT band beam system mimics this strategy of service reticulation and takes some burden off inter disciplinary coordination, which can often be a friction point for practitioners engaging in their first mass timber project,” says Hayes.
The second motivation behind the development of the CLT band beam was that previously, before its development, Australia had limited manufacturing capacity for wide and deep glulam beams.
“This was particularly highlighted during the Covid-19 pandemic when there were significant wait times for Glulam elements,” says Hayes, adding that XLAM’s new product represents an alternative option which can be readily produced locally.
Asked about projects that feature the CLT band beam, Hayes pointed to the Maryborough Fire Station, Australia's first such building to include CLT. An upgrade to the existing art deco brick structure, the project was completed by Hutchinson Builders in association with partners Baber Architects, Bligh Tanner & The University of Queensland.
The design of the new buildings, which include extensive use of exposed CLT and Glulam, was completed with the assistance of 3D building information modelling. According to Hutchinson, this facilitated the off-site design and prefabrication of the individual panels.
Image: Potter Building / XLAM / Photo-Scott Burrows
Thermal efficiency
Architectural Window Systems (AWS), a supply of aluminium window and door systems, takes a different approach to sustainability.
The company’s Series 168 Curtain Wall – as used to great effect at Mutual Bank in Maitland, at 102 Wakefield Street in Adelaide, at the Melbourne Hotel in Perth, and elsewhere – is designed to help maximise the thermal efficiency of buildings, and in so doing, to minimise energy requirements.
Developed to meet ongoing changes to building regulations and in particular Section J of the National Construction Code (NCC), the Curtain Wall is available in three types – Thermally shielded, Thermally shielded with clip on aluminium glazing fins, and Thermally broken.
Designed and manufactured in Australia, the systems achieve impressive thermal transmission performance (Uw values range from 1.7-2.5, and SHGC values range from 0.22-0.33).
Included to protect the thermal break from UV degradation caused by the aggressive Australian sun, the anodised aluminium cap is also an ideal adhesion surface for the silicone weather seal between glass and frame and provides protection from potential hail damage.
Meanwhile, the sun fin bracket is thermally isolated from the mullion, while the mullion members are extruded in T6 alloy for added strength.
Series 168 Curtain Walls accept double glazing up to 32mm thick. Having been tested for compliance with relevant Australian Standards, they have achieved a water resistance figure of 1124Pa.
Mutual Bank’s new Head Office in Maitland, a building completed by North Construction and Building, illustrates the effectiveness of Series 168 Curtain Walls. The project brief called for a striking, modern design that also delivered in terms of energy efficiency.
The design delivered by the architects DWP delivers on both these terms. Featuring expressed mullions, horizontal sunshades, a 105-degree faceted corner and bracketry detail, the building also includes window, door, and curtain wall solutions from AWS’ Elevate Aluminium range.
Specified by Superior Windows, Series 168 Curtain Wall was a key inclusion. Apart from ensuring a Uw Value as low as 1.7 and helping meet thermal efficiency goals, it delivered the flexibility required to facilitate the inclusion of a custom faceted corner and bracketing detail on the structure’s primary facade.
Image: Mutual Bank in Maitland / AWS.
Suppliers
XLAM
Architectural Window Systems
Woodsolutions
AFS Systems
Robertson Façade Systems
