Construction is under way on Melbourne's Southern Star Observation Wheel, the second largest ferris wheel in the world, behind the London Eye, and at 120m, the tallest attraction in Australia.

The wheel was designed by Meisho Japan, and is being constructed at Waterfront City in Melbourne's Docklands precinct, by Alfasi Steel Construction and Tutt Bryant Crane Hire providing the lift planning and major lift crane, with the new 600 tonne Demag CC2800-1 crawler crane.

The wheel is supported on each side by a three-legged stand (tripod) joined at the top by a capital. The legs were fabricated and delivered to site in two halves for final assembly and painting on site.

The legs comprise a 56.2m long, 59.8 tonne vertical column and two bracing columns, one 58.9m long weighing 76 tonne and the other 72m long and weighing 76 tonne. The Demag CC2800-1 with 96 meters of main boom and 300 tonne of Superlift Counterweight has undertaken all the lifts from a fixed pad, while Alfasi's new 150 tonne Sumitomo SCX 1500-2 Crawler Crane has assisted as a tailing crane.

Ground conditions at the site were poor, the lifting pad for the Demag CC2800-1 comprises of a concrete pad 12m x 11m x 2.5m deep, founded on 24 piles, while the path of the Sumitomo SCX1500-2 has been prepared by laying crushed rock over geofabric. The ground at the site has been described as coode island silt. The water table is only some 2.5 meters below finished ground level making the site extremely restrictive with what is able to be achieved with cranes.

Tutt Bryant Crane Hire & Alfasi Steel Constructions spent several weeks planning the project with the use of Autocad for detailed 3 dimensional lift studies that guaranteed that the lifts would be undertaken safely and on schedule.

The 1st vertical leg was picked up from the horizontal with the use of both the cranes, with the Demag raising one end whilst the Sumitomo walked the other end of the leg to a vertical position. The CC2800-1 then placed the leg where it was connected to the foundation and held in place by temporary supports.

A similar process was undertaken with the other 2 legs of the tripod, with the legs first raised to vertical, this operation was complicated by a drain running through the work area. The Sumitomo is not able to cross this under load, so the leg was walked to the edge of the drain, the Demag took the full weight of the leg, the Sumitomo crossed the drain and then reconnected to the load and continued walking the leg into position over its foundations. Both these legs were also supported by temporary props.

The capital was then connected to join all three individual legs into a single tripod stand. This difficult task was made easy by Alfasi's extensive pre-planning and tight quality control.

This process was repeated for the second tripod leg in similar fashion but with less superlift counterweight due to the decrease in lift radius.

The next stage was to pre-assemble the inner hub, 25m in diameter and 8m deep, and weighing 152 tonne when assembled on a temporary assembly stand some 14 meters above the ground. The completed hub was then lifted from the assembly support to a height of 67 meters and placed upon the two tripod legs. This lift was completed within 5 hours. It was crucial that this lift went smoothly due to the weather patterns in Melbourne at that time of year. September and October are the most windy months for Melbourne with gusts recorded at 140 kph only 12 months previousily. The surface area calculations undertaken (490 sq.mtrs) indicated that the crane had a safe wind speed operation of 5.3 meters per second (19 kph). The CC2800-1 placed the 152 tonne wheel at 99% of its capacity with only 1.2 tonne spare capacity left as the hub was fed onto its bearing supports.

The final lifts for the CC2800-1 on this project were the spokes. Seven in total, weighting a mere 27 tonne each. Although well within the capacity of the CC2800-1, the spokes were difficult with each spoke being installed at a different elevation and orientation. The CC2800-1 had to be reconfigured with 108 meters of main boom half way thru the installation of the seven spokes due to hook height and boom clearance issues. Alfasi Steel Construction restrained and controlled the orientation of the wheel from the initial spoke to the final spoke with the use of wire ropes, chain blocks and the SCX1500-2.

The next stage for Alfasi Steel Construction was to assemble the out rim which will be undertaken utilising two SCX1500-2 crawler cranes, one owned by Alfasi and the other hired from Tutt Bryant Crane Hire. The rims were lifted and skated for final connection to the spokes.

Finally, glass cabins will be fitted to the outside of the rim and drive towers installed before commissioning and testing.

The glass cabins will allow those using the attraction, which will open in mid 2008, to have a panoramic view of Melbourne.

The CC2800-1 has been removed from site and is in transit to its next project in Western Australia. Some 45 trucks will be used to moved this monster from Melbourne to Western Australia.