Rail, road, steel: meeting specifications in ‘cold climate’ Sydney

Auburn Railway Station road bridge

The steel of choice for the Auburn Railway Station's road bridge, an important element in Sydney's rail network upgrade, was XLERPLATE® steel grade 350 L15. "This type of plate is frequently used in bridge construction because it provides a very consistent material and a good range of mill ordering sizes to help keep fabrication costs down," said Adua Engineering Contracts Manager, Craig Hogarth.

"The grade of material is extremely important, as is its traceability," continued Craig. "Quality control is a significant issue for our clients and component traceability enables them to track all heat and unit ID numbers for each section of the steel and the location of the XLERPLATE® for each girder."

Adua Engineering has built a strong reputation as a specialist fabricator over the 39 years it has been in operation, particularly for bridge works, for which they are an approved NSW Roads and Traffic Authority (RTA) 'Steel Complex' supplier. This means Adua is 'licensed' to provide services for engineering structures at the more complex and challenging end of the scale.

Adua was commissioned for the Auburn bridge job by Novo Rail, an alliance formed between RailCorp and three private sector companies, Aurecon, Laing O'Rourke and O'Donnell Griffin, to deliver a substantial portfolio of infrastructure across Sydney's rail network. The range of work being delivered by Novo Rail includes the upgrade of rail signalling and power systems to accommodate the introduction of the network's new Waratah trains.

Craig, originally a boilermaker by trade, has been working in the engineering, construction and steel-related industries for 30 plus years, so he's seen his fair share of steel jobs!

"Approximately 230 tonnes of XLERPLATE® steel was used in this bridge, fabricated totally from 350 L15 with the exception of the internal crossbracing angles," pointed out Craig.

Customising to comply with multiple constraints

"The body plates were all specially ordered to extra long size and different widths to suit the special shape of the eight 34 metre long box girder section. These girders had very specific height constraints and had to comply with the existing rail, as well as road and height parameters.

"It is unusual that both rail and road constraints need to be met simultaneously in a specific job, which placed an added onus on BlueScope Steel to supply the most appropriate steel. These constraints were specified by the Novo Rail alliance and resulted in very tailored girders being supplied.

"Another reason for choosing XLERPLATE® steel was that, apart from being able to meet both rail and road constraints, it also needed to have the strength to handle the required loads. We have built many bridges using XLERPLATE® steel and it is suited to our bridge fabrication process," said Craig.

Australian made: Speed, flexibility and cost saving

"The RTA would rather we use Australian made steel. And XLERPLATE® steel is well suited to our needs as it offers a wide range of sizes, enabling us to be more efficient in what we do.

"The very quick turnaround and fl exibility of BlueScope also helps," continued Craig. "Using a local supplier means quick communication, which speeds the job up, whilst an overseas supplier would also have had constraints on the size of steel it could have supplied."

Craig also made the commercially important point that, "Ordering longer than normal plates helped the project as it resulted in less joining, which reduced the need for extra butt welds. This saved time and money."

Interestingly, XLERPLATE® steel was also chosen as it complied with the engineers' requirements for a steel that performs well in low temperatures, which is what Sydney is classified as (though the jury is out on whether the residents of landlocked Auburn would agree with this at the height of summer...).

The XLERPLATE® steel was supplied by OneSteel Steel & Tube and profiled to size at OneSteel Wetherill Park using a DXF cutting computer file, supplied by Adua for the drafting process. The steel was then assembled into webs-top and bottom flanges, then fabricated into eight box girders.

All steel cambers and shapes were cut to size before entering the Adua workshop. The fabrication work from Adua was primarily weld preparation, joining into full lengths sub-assembly welding, assembling into specially shaped box girders, weld testing and final stud fixing.

The XLERPLATE® steel was then delivered to R.E.D. Abrasive Blasting and Protective Coatings for internal and external painting. "The mill finish of the XLERPLATE® steel is excellent with little to no damage to the plate finish," said Craig. "This has resulted in the desired finish to the final painted product, which is also another plus for using XLERPLATE® steel from BlueScope."