Excavated shaft stair
Above Scaffolding were appointed to design and install a 94m stairway access tower into an excavated shaft as part of a very large infrastructure project in Australia.
NorthConnex is a 9-kilometre motorway tunnel under construction in northern Sydney, New South Wales, Australia. When completed it will connect the M1 Pacific Motorway to the M2 Hills Motorway, linking the north to the Sydney Orbital Network and form part of the National Highway route.
Stair access challenges
The project involved a number of access challenges, including stair access into a 94m deep excavation, and then a 90m access/working scaffold to conduct maintenance repairs to a vertical conveyor belt which runs up the wall of the excavation. The client specified the requirement for the stairway to be suspended and to be progressively extended in length to keep pace with the continuous excavation work.
Aluminium Platform Stairs
Addressing high tensile loads and preparing safe assembly methodologies were key design requirements for this project. A clever solution was produced using Layher Allround Aluminium Platform Stairs, in combination with Layher’s 2.21m standards. An extra rosette is a feature of Layher’s 2.21m standard. This rosette allows for stair modules to be split and relocated without any of the conventional requirement for tube and fittings.
Stable excavated stair
Layher’s Aluminium Platform Stairs are stable and lightweight, yet very strong. They are fast to assemble and disassemble, plus they are fully compliant with all New Zealand safety requirements.
The Layher team developed the initial concepts and methodology which involved crane lifting 6.21m modules of Layher Aluminium Platform Stairs.
Stair tower module
The stair tower modules were assembled at ground level. Each module was then lowered into the shaft by crane and connected to the suspended stair tower in one uninterrupted operation, without setting down or double handling. Brian Whelan, Managing Director of Above Scaffolding, said “A safe and highly efficient progressive installation methodology was critical. Layher stair modules up to 6.21m high were installed within an hour ensuring that shaft excavation could progress with little to no interruption.”
Thanks to Brian Whelan of Above Scaffolding for the use of these photos.
Stair access into a 94m deep excavation
A safe and highly efficient progressive installation methodology was critical.
Brian Whelan, Above Scaffolding
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