Already used widely in the United States, weathering steel has hit the Australian market and Hobson Engineering has stepped up to supply weathering steel bolts in metric measurements to meet local demand.
With the Australian construction industry only just starting to ramp up its use of weathering steel in recent months, Hobson Engineering is leading the charge to ensure the high strength steel is utilised for the nation’s long-term infrastructure projects.
To help address Australia’s structural needs, Hobson Engineering is now supplying metric weathering steel structural assemblies.
Alex Sharp, senior engineer at Hobson Engineering, says the company has always championed the latest structural bolting standard, adding weathering steel structural bolts to its already extensive offering in an effort to push the construction industry forward. “Weathering steel is a steel with improved atmospheric corrosion resistance that, in the right environments, forms an adherent rust patina protection that over time will solidify,” he says. “The Australian construction industry has now realised that we have the right climate for weathering steel, given its durable, low maintenance and cost-effective attributes.”
“Hobson Engineering is steering the supply of weathering steel structural assemblies made specifically for the Australian market.”
For over 50 years, weathering steel has been successfully used in infrastructure projects across America, Europe and Japan. Australia does use steels that are better at corrosion resistance than a standard steel, such as stainless steel which builds its own protective coating and doesn’t allow the base material to further corrode. However, these steels still come with the need for regular maintenance.
“Weathering steel is similar to stainless steel in that it builds up this layer that protects the underlying steel from further corrosion,” says Sharp. “So, although it looks like it’s rusty, it’s not continuously rusting.”
“Why this is useful is with most steels, or a basic steel, you need to put something on top of it to protect it – the most common method being to paint the steel.”
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Painted steel doesn’t rust, explains Sharp, because it’s not exposed to the environment. But it needs to be repainted regularly, otherwise the paint blisters and peels off, the steel gets exposed, it rusts and eventually will fail. Another option is to put a sacrificial coating on the steel, such as galvanise, but again, it will degrade over time.
“For most structures and big engineering projects, we don’t want something that’s only going to last 50 years,” says Sharp. “We want to start building structures that are going to last 100 years plus.”
For instance, Sharp says, the Sydney Harbour Bridge requires constant yearly maintenance, costing millions of dollars. But with a material like weathering steel, maintenance is markedly reduced.
“Weathering steel creates a rusty patina that over time hardens,” says Sharp. “Essentially this means it requires no maintenance, which is what everyone is looking for.”
“Instead of looking at how much a structure costs to build, we need to start looking at the savings you can make over the whole life of the structure – this is where you start to see the real benefits of weathering steel.”
Until recently, all weathering steel fasteners imported into Australia had to be sourced from America and arrived in imperial units posing significant compliance challenges for construction project teams. Particularly for heavy industries like construction, compliance to Australian standards is vital to ensure the integrity of structures and the safety of the people using or occupying those structures. Hobson Engineering, understanding its responsibility as one of the leading suppliers of construction hardware in Australia, quickly identified the critical need for weathering steel structural assemblies in metric to guarantee compliance.
“When you try and slot in a product standard from another country or another system, a lot of the detail doesn’t quite match with how our standards are written,” says Sharp. “With our Australian structural bolts, only the first 10 or so pages really tell you how to make the bolt assembly, the rest of the standard, which is a 50-page standard, is all about quality systems.”
“The reason for that is Australia is an importing nation and as importers of construction materials we have the responsibility to know what we are importing because these materials are going into structures that, if they fail, could cause serious injury or loss of life.
“Realistically, you can say a lot of things to a factory, but businesses need to be checking that it’s actually happening.”
That’s why Hobson Engineering has put rigorous systems in place to ensure that the factory suppling its weathering steel structural bolts is manufacturing to the correct standards. To ensure these bolts are fit for purpose in Australia, Hobson Engineering completes Rotational Capacity Testing of all its weathering steel structural assemblies.
In Australia ASTM A325M is the standard specified where structural bolts made from weathering steel are required. With this American product standard that the nation is using, there isn’t as much quality management embedded as is expected in local steel structure codes such as AS 4100 and bridge design code AS/NZS 5100.6. Without having it in the standard, companies importing directly from the United States are missing a lot of these quality checks that they would otherwise have with an Australian structural bolt.
Recent weathering steel projects in Australia have faced a number of challenges with imported imperial bolts. To tackle this issue, Hobson Engineering has integrated the quality systems from the Australian standard into the ASTM standard. “We now have the American weathering steel bolt in metric, with all of the quality systems required to meet compliance in Australia,” says Sharp.
“By supplying these assemblies in metric, we expect to see a more streamlined delivery of future projects in regard to compliance, quality and speed of procurement.”
With supply chain issues continuing to affect the industry and sustainable construction becoming a key requirement in project designs, it’s never been so important for contractors to consider the materials they are using.
Hobson Engineering’s business model is focused on having stock on hand. Fasteners are one of those things that project teams think about last minute, says Sharp, but should be looking at early in the design phase. “We see businesses design a complex project and not question how they’re going to get the materials supplied,” says Sharp. “They then go hunting around for it at the very last minute when they need bolts delivered within a week or two.”
“Project teams historically were required to change designs to suit availability and experienced delays because delivery had to come from the United States, which took up to 14 weeks.”
By having metric weathering steel structural assemblies in stock for the Australian market, contractors can start designing projects without the worry of facing delays or compliance and rework difficulties later down the track.
As the Australian construction industry continues to move towards a reduced carbon footprint, weathering steel also poses great sustainability benefits. Weathering steel was designed to reduce maintenance, the use of paints and chemicals, and reduce the cleaning and safe working required to maintain steel structures.
“Once a weathering steel structure is constructed, no maintenance is required other than every now and then having to give it a spray down for graffiti,” says Sharp. “These benefits are key reasons why Hobson Engineering has stepped up to supply quality weathering steel structural assemblies, in metric and made for the Australian construction sector.”
As Australia accelerates its use of weathering steel to create the sustainable, safe and durable structures of the future, Hobson Engineering is ensuring it’s ahead of the game with its metric weathering steel structural assemblies in stock, ready for the next big project.
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