Architect and Builder Oct/Nov 2017 | Page 27

The roof structure had to be developed in such a way that large spans were incorporated with minimal impact on the structure below. The roof geometry was relatively complex, however the design solution needed to be relatively simple to enable easy installation on site. The roof structure and associated feature columns were designed and constructed with structural steel lattice trusses, girders and lattice columns. The lattice structure in turn is clad with smooth aluminium cladding giving the roof structure the crisp finish that was desired. The structure supporting the multi-level façade also provides vertical support for the roof structure. This structure was designed and constructed with conventional I and H structural steel sections. The roof and façade structure are braced to the adjacent reinforced structural buildings which provide the required lateral stability for these structures. The atrium areas also had feature columns that were constructed from welded up structural hollow sections. A number of these columns are features with no structural significance, however three of these columns are design to provided vertical support for the roof structure. BCX HVAC An energy efficient variable air volume system supplies conditioned air from air handling units located on the façades. The cooling source is provided by air-cooled chillers located on the roof, not using any water. Fresh air is drawn at high volumes from the façade plant rooms to ensure a healthy environ- ment and minimise energy usage when outside conditions are favourable. Carbon dioxide levels are monitored and controlled in the office areas to enhance indoor air quality. The basement ventilation system controls Carbon Monoxide levels to ensure a healthy environment and minimise energy usage. Various tenant server and data areas are served by close-control computer room air conditioning systems linked to the central chilled water system. A full BMS system monitors and controls all HVAC systems to optimize energy usage. All key building services are centrally monitored and logged by the BMS (water meters, energy meters, lifts, escalators, heat pumps, fire systems and sump pumps). 27