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Stainless integral to bridge's 300 year design life

Queensland’s largest ever road and bridge project will rely, in part, on innovation within the stainless steel industry to meet its design life of 300 years.

The Gateway Upgrade Project in Brisbane, which includes construction of a second Gateway Bridge and is being delivered by Queensland Motorways with design, construction and maintenance by the Leighton Abigroup Joint Venture (LAJV), will use reinforcement bar made for the first time from Outokumpu Group’s LDX 2101® duplex stainless steel.

A total of 130 tonnes of duplex stainless steel will be used in the bridge’s most critical structures: the splash zones of the two main river piers (28 tonnes of LDX 2101® have already been supplied and some Duplex 2205 will be used due to availability of dimensions for certain components).

Gateway Bridge Alliance Manager Gerry van der Wal said LDX2101® was chosen due to its high level of corrosion resistance (close to 316L) and low nickel content, which made it more cost effective and less susceptible to rapidly escalating worldwide nickel prices.

Outokumpu’s Qld and NT Manager Ken Hayes said that in bridge construction, stainless steel should be specified for parts where it makes a positive contribution, such as splash zones and the bridge deck.bridgepillar

“If carbon steel rebar is used, the bridge deck needs a water-proof membrane and the concrete must be of high quality, whereas if stainless rebar is used, reduced concrete cover can be specified, and it is also possible to relax the design criteria with respect to maximum crack width,” he said.

“As a result, with stainless rebar, bridges can be built either with no extra cost or for a lower cost than by using carbon steel reinforcement.”

Mr Hayes said LDX2101® offered the most cost-effective alternative for durable reinforced concrete structures and, due to its good price stability, it offered construction projects vitally important predictability.

“The win-win outcome from the use of LDX2101® is much improved sustainability in our constructed environment,” he said.

Because LDX2101® had never been used for rebar before this project, Outokumpu’s metallurgists carried out extensive tests to ensure it would withstand a high corrosion environment if the concrete were permeated by seawater.

A trial rebar coil was also sent to Atlas Specialty Metals’ Durinox facility in Melbourne to ensure it could be easily straightened.

Durinox Manager Colin McGill said they had to decoil the material, cut it to length and bend it to the appropriate shape.

“This was the first time we had processed the material and there were some challenges we had to overcome because of its very high strength,” Mr McGill said.

Once Outokumpu’s quality system and external testing criteria were approved by LAJV, the initial 28 tonnes of the hot rolled, ribbed, 16mm LDX2101® were delivered to Atlas Specialty Metals in Melbourne in 750kg coils for processing between October and December 2007.

The $1.88 billion Gateway Upgrade Project will be completed in 2011. It includes duplication of the original Gateway Bridge (which was completed in 1986), upgrade to 12km of the Gateway Motorway and construction of a new 7km deviation providing better access to Brisbane Airport.

Just over 20 years after it was constructed, the original Gateway Bridge is now exceeding capacity, carrying more than 100,000 vehicles each day.

When the duplication project is complete, the original bridge will carry six lanes of traffic north and the new bridge will carry six lanes of traffic south.

The new bridge is a 1.6km long balanced cantilever motorway bridge with the main span measuring 260 metres.

This article featured in Australian Stainless Issue 42 - Summer 2008.

Photos courtesy of Leighton Abigroup Joint Venture.

Stainless by the bus load

Newcastle's public transport stocks are to be boosted by the addition of 30 new stainless steel buses, the first of which was delivered this month.

Their advanced design combines passenger comfort with environmental awareness. The Volvo B12BLE bus chassis meets the latest Euro III exhaust emission standards, making it the cleanest diesel bus on Australian roads.The buses are being built by Custom Coaches, the largest Australian bus manufacturer with plants in New South Wales, South Australia and Queensland.

The buses are being built by Custom Coaches, the largest Australian bus manufacturer with plants in New South Wales, South Australia and Queensland. Stainless steel supply is by ASSDA member Fagersta Steels.

The buses have features to make travel easier for visually impaired passengers and those with restricted mobility. They include air-conditioning, anti-lock brakes and graffiti-resistant seats.

In commissioning the buses, the State Transit Authority of NSW emphasized economical operating and maintenance costs, fuel efficiency and competitive whole of life costs. International experience shows stainless steel delivers on these criteria thanks to its corrosion resistance, durability and weight-saving qualities.

The outlook for stainless in bus construction is positive, as more Australian bus owners and operators are becoming aware of the merits of stainless steel bodies compared with traditionally used coated carbon steel. In response to anticipated demand, Custom Coaches is currently investigating a range of stainless steel grades for future contracts.

This article featured in Australian Stainless magazine - Issue 24, March 2003.

Stainless bus carries industry savings

Significant petrol savings, longer service life, lighter tare weight and reduced maintenance costs are just a few features of Australia's first stainless steel bus.

Two prototype buses with grade 304 stainless steel body shells are being manufactured by Gold Coast-based company, Bus Tech Pty Ltd for Volvo Australia.

Stainless steel buses are used extensively in Europe and the United States of America to guard against corrosion caused by icy, salted roads. Corrosion of buses is also a problem in Australia with vehicles subject to regular frame inspections and refurbishment costs. Corrosion in buses results not only from exposure to marine environments, but also from humidity and condensation and recycled water used for cleaning.

Bus Tech Manager, Frank Reardon, said the stainless steel bus had many advantages including corrosion resistance, reduced maintenance and operating costs.

"What will be extremely advantageous for operators is tat they can keep the stainless steel buses on the road for 10 to 15 years without having to constantly address corrosion issues common with carbon steel buses," Mr Reardon said.

A 700 kilogram reduction in tare weight of the bus has been achieved by using stainless steel, resulting in a $2 per kilometre saving in petrol and the ability for each vehicle to carry an additional nine passengers.

"With the increasing price of fuel, we were pushed by our clients to find a way to reduce the tare weight of the bus," Mr Reardon said.

"Using stainless steel has allowed us to provide this extra benefit."

A 15% reduction in production time has also been a feature of the stainless steel bus project.

Each bus is being constructed from 200 metre of square hollow sections (SHS) and 600 kilograms of stainless steel sheet, all grade 304 with a 2B finish.

The exterior and interior of the buses are attached to the stainless steel shell with a polyurethane adhesive, providing a bond line to keep out water and dust.

The exterior and interior of the buses are attached to the stainless steel shell with a polyurethane adhesive, providing a bond line to keep out water and dust.Fabrication of the stainless steel components was undertaken by Brisbane fabricators Metal Tech Industries and BJR Metal Rolling & Pressing, then delivered to Bus Tech for assembly. Stainless steel for the buses was supplied by ASSDA member Austral Wright Metals.

ASSDA provided literature and an in-house stainless steel seminar during the planning stages of the project.

The buses will be delivered to companies in Liverpool, New South Wales and the Gold Coast.

Mr Reardon said Bus Tech was pleased with the project and hopes to adopt stainless steel as a standard for their buses.

This article featured in Australian Stainless magazine - Issue 18, May 2001.

Making Over the MCG with Stainless Steel Technology

The Melbourne Cricket Ground (MCG) or the ‘G’ as it has become affectionately known, has an important project deadline.

The national sports icon is currently undergoing a redevelopment in preparation for the 2006 Commonwealth Games to be held in March.

When complete, the ‘G’ will boast three impressive glazed entry structures over the Ponsford Gate, the Members Entrance and the Olympic Stand Entrance, each with its own network of high tensile stainless steel members.

The project is a collaboration between Ronstan’s architectural division and steel contractor, Materials Fabrication.

ASSDA member, and Australia’s own world leader in tension structures, Ronstan Architectural Rigging Systems, has been intimately involved in the supply of stainless steel tension rods on the project.

Ronstan looked at the loads required and selected the material grade for the specific tensile characteristics. This allows for the optimal efficiency of the tendon in transferring the load, a key requirement in lightweight tensile architecture.

In this case the ‘G’ structures included 600 tendons with adjustable fork ends manufactured from approximately two kilometres of 19mm grade 316L stainless steel bar.

These were polished to a No. 7 finish and passivated to achieve the required aesthetics and longevity.

“The challenge was to compliment a great product with the right mix of product support,” said Rowan Murray, General Manager of Ronstan Architectural Rigging Systems.

Images courtesy of John Gollings.
This article featured in Australian Stainless magazine - Issue 32, Winter 2005.

Duplex to Shine in DNA Design

An Australian-led design consortium will put a new twist on bridge construction with a 280 metre long stainless steel pedestrian bridge spanning across Marina Bay, the foreshore to Singapore's CBD. The bridge will link the highly anticipated Marina Bay Sands resort to a bayfront promenade linking major cultural, tourist and recreational sites.

Selected from a field of 36 international teams, the design team, incorporating Australian architects the Cox Group, engineers Arup and Singapore-based Architects 61, has designed an entirely new concept in bridge construction, based on the double helix structure of DNA.

The double helix will carry a metre wide pedestrian walkway running parallel to a six lane vehicular bridge, which is part of the same $68 million project.

Arup senior associate Greg Killen said the pedestrian bridge was a true world first, in that it did not use any of the known support mechanisms which categorise all bridges built to date. The shape of the bridge can be described as two slinkies, one stretched out slightly further than the other, flipped, and then placed inside the first. This shape is then doubly bent to form a smooth curve.

As far as we know, this design direction has not been explored before, Mr Killen said.

An Arup-designed structural optimisation program confirmed the unique design concept offered substantial structural performance.

Mr Killen said the helix tubes touch only under the deck and the unravelling forces were captured elsewhere by light stiffening rings that hold the opposing tubes apart (rather than together) in a kind of structural magnetism.

The concept enabled the use of five times less steel than a conventional box girder bridge of the same length, which meant the budget would run to the use of stainless steel.


We chose to design in duplex stainless because we've used it on a number of projects before and while the strength is comparable to structural mild steel, the maintenance costs are reduced and the total life of the bridge is extended beyond 100 years, Mr Killen said.

There is a perception in the marketplace that the cost of grade 2205 duplex is much more than austenitic varieties such as 316. This is not the case and while there is great fluctuation in both prices, the fabrication costs are similar (although some of the processes are slightly different).

The higher strength of 2205 makes a big difference, especially on longspan structures where the self weight is often the major design driver. 2205 also has superior durability including resistance to the tea staining that plagues many austenitic structures.

Singapore, a busy air hub with a very small land area, has become well respected for the quality of their buildings and infrastructure.

Singapore is not only clean and leafy, there is a noticeable emphasis on quality urban design. The urban landscape includes extensive use of materials such as stone, glass and metals where Australian cities may favour cheaper, less durable solutions. This makes Singapore the perfect platform for the world's first double helix bridge, Mr Killen said.

The project will use 370 tonnes of duplex stainless steel for the superstructure, including pipe, and welded plate and tapered sections. Stainless finishes selected by the Cox Group include a combination of bead blasting and polishing, with one of the slinkies to be highly polished and the other bead blasted, using olivine, a magnesium silicate medium.

The project, which is currently out to tender, is expected to begin construction at the end of this year and be completed in 2009.

Images courtesy of Arup + Cox + Architects 61
This article featured in Australian Stainless magazine - Issue 37, Spring 2006.

Whole of life costing

19 years plus points to stainless

A fresh focus on whole-of-life costing at Gold Coast City Council has led to the specification of stainless steel for long-term structures in the foreshore zone.

The philosophy, which was adopted following the publication of a study by Griffith University and GCCC, is likely to have flow on effects to other councils and government bodies.

GCCC’s co-ordinator of technical governance Paul Conolly said the seed was planted in 1998 when Council’s Technical Services Branch specified stainless steel for a modular toilet structure in a foreshore zone park. The material was deemed at the time to be cost prohibitive on a capital expenditure basis but the process sparked an interest in lifecycle costing.

Mr Conolly said Council’s growing interest in lifecycle costing, combined with an expectation among locals and tourists that public facilities showcase a ‘resort style’ finish, had brought the focus back to stainless steel in recent years. “There has been a clear trend towards lighter, more open structures for public facilities and these lend themselves to steel work,” he said. “A lot of our public facilities are in the foreshore zone and some materials weren’t performing as well as we wanted, so we started to look at corrosion issues and how to best manage this. We started using stainless steel for critical elements, such as joint interfaces for concrete works; bolts, brackets and cleats for boardwalks; and for high use facilities such as rubbish bins.

“Our observations led us to believe that stainless was the way to go in the foreshore zone, but we had no tangible justification which the designers could use to validate the decision for our asset custodians. We needed clear evidence to prove the initial cost of stainless steel was justified over the life of the structures.”

Griffith University scholarship student Jordan Cocks was called on to research the topic in conjunction with industry affiliate GCCC as partial fulfilment of his Bachelor of Civil Engineering.
Mr Cocks investigated multiple structural scenarios from the perspective of what would represent the most cost-effective solution: hot dipped galvanized (HDG) steel, paint systems, duplex systems using both HDG and paint, or stainless steel.

The result was a report containing a design guide, a life cycle cost analysis and a life cycle costing spreadsheet for structures in the foreshore zone. The report indicates stainless steel is a viable option based on cost alone for structures with a design life greater than 19 years. Conversely, the study indicates a HDG coating would theoretically have a life span of 14 years, leaving the exposed steel subject to rapid corrosion unless protected by an increasingly costly maintenance regime.

Mr Conolly said the report had delivered a workable tool enabling designers to input various parameters, such as current prices and design life, producing a guide for selection of the appropriate material or finishes based around optimising whole-of-life costs.

Similar principles were used to shift the specification of a park arbour in Broadbeach towards stainless steel. The material was essential due to the warm, humid environment of the foreshore, regular spraying with water and fertiliser, and the fact that the arbour would have plants growing over it that would take many years to fully establish. The report has now been used to guide material selection for a number of projects, including toilet blocks in Jacobs Well, Miami (pictured) and Burleigh Heads.

“With these projects, we have gone to the asset custodians and our first question was – what is the design life?” Mr Conolly said. “The report has helped reinforce the need for a ‘cradle to grave’ approach to responsible and sustainable asset management encompassing all stakeholders. This includes not just the designer and asset custodian but all the operational and maintenance personnel involved with a structure.

“For stainless steel structures, the asset custodians now recognise that to retain an asset over the long-term and to satisfy the whole of life cost advantage there must be regular wash downs as part of the maintenance program. The higher initial construction costs are offset by the lower cost regular wash downs which form the major component in the new maintenance regimes. The buildings are also being designed to be hosed from ceiling to floor. The overall process has really helped improve the relationship between the asset custodians, designers and maintenance staff.”

Mr Conolly said the report had also been used to promote the use of stainless steel in playground equipment and shade sail structures. “It is just a matter of making that little leap towards recognising the whole-of-life cost and ensuring delivery of a durable product – it’s not rocket science, just common sense when you think about it.”

GCCC is also now favouring ASSDA Accredited Fabricators and looking to ASSDA to provide third party technical expertise or adjudication should conflicts arise relating to material performance. The ASSDA Accreditation Scheme requires fabricators to conform to stringent standards of competence, training and education and encourages a consistently high standard through industry self-regulation.

ASSDA Executive Director Richard Matheson said GCCC’s decision to favour ASSDA Accredited Fabricators and specify stainless steel in the foreshore zone was a welcome one. “I believe we will see this initiative mirrored by other councils and government bodies in the near future,” Mr Matheson said.

“There is no doubt that informed specification and quality fabrication by people who know and understand the material will offer long-term cost savings and extend the life of the product. This is why ASSDA places so much emphasis on education and technical expertise – Councils and other government bodies need to get it right the first time and ensure value for money for their constituents.”

Mr Conolly said for long term structures, stainless steel was becoming the default specification in the foreshore zone and the trend was even moving inland.

“We’re asking the question: what will look and perform best from cradle to grave? It’s making people think differently,” he said.

Download the the final report here (4.6MB) - Whole of Life Cost Comparison and Cost Benefit Analysis for Steel Structures Constructed in the Foreshore Zone.

GCCC close up GCCC close up 2
This article featured in Australian Stainless magazine - Issue 48, Autumn 2011.

Water Farming

Stainless Technology Essential

Guaranteeing water supply in Australia is thirsty work. Western Australia’s new Southern Seawater Desalination Plant, currently under construction north of Bunbury, will help quench Perth residents and businesses with up to 100 billion litres of water a year. In such a highly-corrosive salt water environment stainless steel is a natural fit.

Sea water is pumped from the ocean and its high salinity is extremely corrosive. The desalination plant uses reverse osmosis to purify the sea water, essentially pushing it through a fine membrane at high pressure.

The first pass (first membrane) is the most corrosive environment which is why super duplex stainless steel is essential. Following passes, which have much lower levels of salt and are almost fresh water, require duplex and grade 316 stainless steels.

A collaborative effort of WA stainless steel expertise ensured the best knowledge was applied to the 200-plus tonnes of piping in the plant.

Alltype Engineering was contracted to supply the complete reverse osmosis racks (see image above) with super duplex, duplex and 316 stainless steels required for all the connecting pipe spooling. Project Manager Keith Thomas-Wurth said the the energy recovery devices and the pipe spooling connecting the reverse osmosis racks with the pressure pumps were subcontracted to ASSDA Accredited Fabricator Weldtronics Australia.

International Corrosion Services’ pickling and passivation treatments were central to ensuring the performance of the stainless steel entering the plant. They use Avesta Finishing Chemicals supplied by Bohler Welding Australia (a division of Bohler Uddeholm Australia).

ICS Business Development Manager Stuart Norton said the opportunity to apply the pickling and passivation processes to 200 tonnes of piping came at the right time.

“We’ve just developed the largest nitric and hydrofluoric acid tanks in the southern hemisphere, and they’ve been used to treat the stainless steel to ASTM380-06,” he said.

The near 20m3 tank is a realisation that the industry will move towards longer pieces, particularly in piping, saving on fabrication time and reducing the number of joins – ultimately providing less opportunity for corrosion.

Southern Seawater Joint Venture Mechanical Engineer Juan Jose Perez said that the stainless steel piping in particular is one of the most important elements of the desalination plant’s construction.

“The membrane is the core of the plant and, in turn, the core of the filtration process. The salt water is passing through the stainless steel pipes to get to the membrane and any corrosion, any tiny particle, can damage the membrane which is extremely expensive,” Mr Perez said.

“Suppliers of the membranes run regular checks to detect for corrosion and, if they detect it, it could potentially affect functionality, even warranty of the membrane. So we rely on the stainless steel, particularly inside the pipes, to be of the highest quality. This is why the pickling and passivation process is so important.”

Mr Norton said that ICS heard the industry screaming out for larger tanks for pickling and passivation jobs such as the one undertaken for Southern Seawater and undertook the two-year journey to get the required authorisation.

“Obviously there are some key environmental and waste treatment factors involved in this. Our waste-water process was made easier by constructing an in-house acid neutralisation tank plus a filter press to push heavy metals out of the acid before sending it off to be further treated,” he said.

The trend towards desalination as a water supply method is clear: when Southern Seawater comes online in late 2011 desalinated water will account for 30 per cent (up from 16 per cent) of WA’s total water supply.

This trend means that further use of large-scale pickling and passivation is likely as stainless steel continues to prove to be an essential and trustworthy component of the desalination plant’s construction.



This article featured in Australian Stainless magazine - Issue 47, Spring 2010.