The major design features of the Control Tower include a cable stayed precast supporting column structure combined with an external passenger lift both of which are entwined by an enclosed sweeping spiral stairway running from the ground level to the control chamber.
The control room complex is supported on a 20m high segmental precast shaft, 2.5 m in diameter but with a truncated flat face against which the passenger lift structure is fixed. This shaft is vertically pre-stressed in stages to its moment resisting foundation using 31 No high strength stressbars. These bars connect directly at the top of the shaft to the upper steel control room support column, thus providing its stability. Off-white cement and a Class A, colour controlled off-form surface finish was specified. The achievement of such highly durable and aesthetically pleasing surfaces in a dimensionally exacting construction is testimony that large functional and large structurally important elements are able to satisfy structural complexities simultaneously with high architectural expectations.
Concrete Institute of Australia Excellence in Concrete Entry 1995 - for details of CIA entry in .pdf format, click here