OSDP Wall Rotation

//OSDP Wall Rotation
OSDP Wall Rotation 2019-09-27T09:30:39+10:30

Building 22 – Block Outfitting and Ship Erection Hall

The Osborne South Development Project (OSDP) at Mersey Road involves the construction of three large, new industrial buildings – a Steel Fabrication and Unit Assembly Hall, a Block Assembly Hall, and a Block Outfitting and Ship Erection Hall.

A Paint and Blast Hall is also being constructed, along with small ancillary buildings and a canteen.

These Halls will house BAE Australia / ASC Shipbuilding’s operations for the construction of nine Hunter-class Frigates as part of the Commonwealth’s Naval Shipbuilding Plan.

The Question

The largest building – the Block Outfitting and Ship Erection Hall – is 187m long and 87.4m wide and stands at 50 metres high. It features a steel portal framed structure comprising approximately 4000T of structural steel, founded on a piled 1m thick slab pavement.

To build such a structure, conventional construction methods involved extensive works at height and the design and installation of considerable temporary works – both posing significant risk to safety and program.

The question was, how could the Hall be built to reduce the need for works at height and to streamline the construction process?

The Solution

 

Modules are constructed on the ground

The safest and most expedient solution was to build the walls and roof at ground level, enabling the bulk of works at height to occur at a maximum of 17m rather than 50m, streamlining the construction process and reducing temporary works requirements.

This solution has involved dividing the building into modules – ten wall modules and two roof modules – then staging the construction of each module at ground level. Construction at ground level includes all structural steel works, external cladding, and the installation of services and fixtures, etc.

The process requires the construction of ten wall modules and two roof modules

                                                                     

On completion, each wall module is then rotated into place with hydraulic jacks using strand-jacking methodology.

Originally designed for concrete post tensioning systems, strand-jacking is used to lift very heavy loads on construction and engineering projects, such as the erection of bridges, lifting of rooftops, major buildings and other structures where the use of conventional cranes is impractical.

Since multiple jacks can be engaged simultaneously using hydraulic controllers, they can be operated in tandem to enable the lift of very large loads. In this instance, each wall module weighs approximately 220 tonnes, and the two roof modules weigh 440 tonne and 750 tonnes respectively.

Concrete blade walls circle the perimeter of the Block Outfitting and Ship Erection Hall in readiness for the installation of gantry cranes and other equipment that will be used in the construction of the Hunter class Frigates. These are used to support eight hydraulic H200 jacks which are needed to lift each wall module and have been specially constructed to support the additional horizontal load created as each module is lifted into place.

The wall rotation process

Once a wall module is rotated into place, temporary props are installed and the jacks are disengaged and reused for subsequent modules.

This method is repeated for the next module and once rotated into place, infill members are installed between the wall modules.

This process is best illustrated in the time-lapse footage above.

Roof modules

Using a similar methodology, two roof modules are also pre-assembled on site, including temporary works and bracing. Once complete, each roof module is lifted into place using strand jacks installed and supported on top of the erected wall modules.

Weighing in at 585T and taking nine hours to raise, the first roof lift was successfully completed in September 2019. Over the next eight days, pairs of Riggers working out of four 180ft boom lifts secured the roof to the wall sections using 352 bolts.

29 local workers were involved in the lift and bolting process, with 4000 man-hours saved by building the roof structure on the ground.

The second and final stage of roof to be lifted for the 187m long, 87.4m wide building is larger and heavier and is expected to take ten hours to lift into position.

Key consultants and contractors involved in developing the wall rotation solution in collaboration with ANI and managing contractor, Lendlease, were:

  • Australian Naval Infrastructure Pty Ltd (Shipyard owner / developer)
  • Lendlease (Managing Contractor)
  • SA Structural (Structural Steel Supply & Erection)
  • Freyssinet Australia (Heavy Lift Specialist)
  • Robert Bird Group (Temporary Engineering)
  • Kina Consulting (Third Party Engineer)
  • Aurecon (Base building structural Consultant)
  • McMahons Roofing (roofing and pre-fabricated roof vents)
  • NSG Boffa (Electrical Services)
  • O’Connors (Mechanical Services
  • Jordan Plumbing (Hydraulic Services)
  • Trojan Fire (Dry fire installation pre-lift)