One primary functional requirement for the facility was a column-free, 20 metre radius semi-circular Control Theatre area, where conditions on the transit lines could be displayed and monitored on computer consoles and screens.  For this threatre, operating control use, noise level control by sound absorption, equipment isolation, and appropriate selection of structure were important matters.  Placement of the new building on a sloping site required structural resolution of significant lateral forces applied to the earth retaining sub-structure.  Consideration of residential areas adjacent to the site influenced aspects of the building layout. 

The hybrid structural solution for this challenging three storey building is two storeys of structural steel framing atop one storey of reinforced concrete framing.  The structural concept developed by us made best use of the capabilities of structural steel and reinforced concrete, and provided a serviceable and economical building structure.