Southern Cross StationEdit profile
The commission for the redevelopment of Melbourne�s Southern Cross Station (previously known as Spencer Street Station) arose out of the need for an upgraded terminus to accommodate the anticipated rise in demand for public rail services. The brief required a fully integrated transport interchange, which would provide essential public transport upgrades as well as pedestrian connections between Melbourne�s Central Business District (CBD) and the developing Docklands area. This increased connectivity would encourage regeneration and improve commercial growth locally. These pragmatic requirements only tell half the story; the client�s unwritten aspiration was for a building that would become etched on the memory as a world-class symbol for the city of Melbourne. Implicit in the decision to appoint an internationally renowned architect is an interest in the �grand gesture� of the train station as a civic monument. It suggests an ambition for more than just an efficient and functional building, but also one that would make a substantial difference to a community. Grimshaw was appointed to work in collaboration with local practice; Jackson Architecture on the reorganisation and expansion of the existing station. The design team worked as part of the Civic Nexus Consortium, with financiers ABN Amro and Leighton Contractors, which at that time was Victoria�s largest public-private partnership (PPP). Spencer Street Station is the only one of the five stations on Melbourne�s City Loop to serve both regional and interstate rail as well as bus connections, and is as such Melbourne�s �Central Station�. The transformed station, now named Southern Cross Station, improves intermodal transfers between the rail, bus, tram and taxi services. It has been expanded to handle the anticipated level of growth and potential new rail services, including the potential Fast Rail Link services to Sydney and the �Airport Train� to Melbourne International Airport. As well as the transport interchange (and associated track and signalling works) the redevelopment includes a major office building on Collins Street and a retail plaza serving the CBD�s west end. This creates a new commercial focus for the regeneration of this part of the city and encourages pedestrian access between the CBD, the Telstra Dome Stadium, and associated venues. A north-south pedestrian bridge will be introduced to the western boundary of the site, allowing the docklands to connect with the station over the Wurundjeri Way freeway and continuing the city�s established grid westwards. The elevated commercial redevelopment is planned to complete this western end of the station. The key generators for the station were always practical performance, ease of passenger circulation and an improved working environment for staff. The newly refurbished Southern Cross Station provides the 15 million users per annum with fully sheltered, high-quality ticketing, baggage-handling, waiting and retail services, all equipped with comfortable seating, lighting and passenger information display systems. Internally it is a vast hall, with uninterrupted vistas in every direction so that the interconnection of surrounding streets can be easily understood. Pods of accommodation beneath the roof, house administrative functions as well as providing a defined retail space below. The design focus of the station is the dune-like roof that covers an entire city block: it works as a visual bridge between the city centre and the new docklands, providing a �gateway� to the city. On a functional level, it unites all the disparate elements of the interchange, providing a cool, shaded space at a civic scale. The roof�s form has been generated by the performative requirements of the station and plays a crucial role as part of the environmental envelope. Environmental concerns were central to the brief, so this undulating blanket roof was developed in response to the hot external climate and the internal need for diesel extraction and ambient cooling via natural ventilation. While it is waterproof to the outside it seems to breathe internally, allowing smoke, diesel particles and contaminates to be discharged to the outside. The individual roof moguls act as air reservoirs that collect hot air together with the train�s diesel fumes. The hot air and fumes are drawn through the roof, via louvres at the apex of each mogul, by the prevailing winds. These north-west and south-west winds define the valleys that cut across the roof form, ensuring natural ventilation year round. This solution is a contemporary reinterpretation of the historic shed roofs of nineteenth century Europe. Cross ventilation on the interior is required for these climate control and diesel extraction methods to be efficient. The internal thermal air currents combine with the exterior prevailing winds to help force the trapped air through the mogul apexes. Consequently the station can be seen as a modified external environment with the roof as the only containing element. The glazed panels of the facade are held away from the ground and the roof structure, allowing air to pass freely through the station. Another reason for the elevations to be as visually and structurally light as possible is to ensure visual continuation between the street and the station concourse. It is hoped that the vibrant concourses, separated from the pavements only by a partial glass facade, will enliven the major streets � Spencer, Bourke and Collins Street � that bound the station, contributing to the regeneration of the immediate community. The roof system is devised from complex geometry, with no repetition or symmetry. In spite of this, rapid prototyping ensured individual truss sections could be designed and then prefabricated at reasonable cost. The roof�s structural grid is formed by a series of circular hollow section tubes that connect to one another laterally through a radiused contra-flection, providing a continuous mesh. The grid has 40-metre centres in both directions; this minimises the structural connection points to the ground thus optimising visual transparency and spatial flexibility. In order to diffuse the sense of weight from this massive structure, the spine trusses are covered with a continuous strip of ETFE pillow cladding. Unlike glazing, which could weigh down the structure both physically and visually, the ETFE pillow enhances the illusion of transparency and lightness.