Big Wheels Turning Soon

Location:	Waterfront City, Docklands Area, Melbourne
Country:	Australia
Project Size:	650 tonnes of Grade 350 XLERPLATE® steel
Client:	ING Realestate Developments
Engineer:	Sanoyas Hishino Meisho
Fabricator:	Haywards Steel Fabrication and Construction
Project Team:	Alfasi Steel Construction Hansen Yuncken
Products Used:	AS/NZS 3678 - 350 XLERPLATE® steel

Melbourne's latest tourist attraction is beginning to take shape at Waterfront City in the redeveloped docklands area.

The Southern Star Observation Wheel is set to be the centerpiece of Waterfront City, which will also house three levels of retail, commercial, office and function spaces.

Commissioned by ING Real Estate Developments and designed by Japanese company Sanoyas Hishino Meisho, the Southern Star Observation Wheel is a showcase for Grade 350 XLERPLATE® steel.

Construction started in January 2006 and is expected to be completed by October.

Melbourne based Alfasi Steel Constructions is working alongside head contractor Hansen Yuncken on the project, overseeing a number of suppliers and subcontractors and managing project elements such as steel detailing, fabrication, erection, electrics and commissioning.

"It might not be the biggest project Alfasi has done, but it's unique," Alfasi Project Manager Steven Downes said. "It's different to the London Eye or The Singapore Flyer because it has a star shape structure at its core, rather than bicycle wheel style spokes of the Eye and Flyer."

The complexity of the design, and the installation of the drive and braking system, electrics and 21 mechanically rotating cabins, involved much preplanning by Alfasi. "We spent four months in concept development sessions to meticulously plan exactly how we were going to undertake every single step of the project," Mr Downes said.

"A difference of just three millimetres between the elevations of the two towers would throw the wheel out by 20mm at ground level. So, despite the considerable scale of the structure, we really do have to work within tolerances of mere millimetres."

Alfasi has used over 650 tonnes of Grade 350 XLERPLATE® steel from distributor OneSteel in the 110 metre diameter project. Each cabin weighs 14 tonnes, with the entire structure expected to weigh 1,600 tonnes.

The cabins sit on the external ring of the wheel. Each cabin seats 20 people and sits inside a special ring that holds it upright as the star rotates.

The star has seven spokes, each weighing 22 tonnes. They are fixed to the inner-ring hub which is 60 metres above the ground. Project subcontractors include Tasmanian company Haywards Steel Fabrication and Construction, which is manufacturing the wheel’s 74 metre high structural columns.