Architects: Baulderstone Hornibrook Queensland & Cox Rayner Architects
Location: Brisbane, Australia
Design year: 2007
Construction year: 2008-2009
Structural Engineer: Baulderstone Hornibrook Queensland Pty Ltd and ARUP Engineers
Budget: $63,3 million
Images: Cox Rayner Architects
Tank Street Bridge is getting a lot of attention as the first large scale tensegrity bridge. The bridge is currently under construction in Brisbane’s inner city. Brisbane is one of today’s fastest growing urban centers in Australia and the bridge is part of the City Centre Master Plan 2006 anticipating an increasing demand for pedestrian areas. It will link the city center to South Brisbane: from Tank Street to Kurilpa Park traversing Brisbane’s navigable river. The construction of the Tank Street Bridge is expected to be completed by September 2009 so that it can be part of Queensland’s 150th year anniversary celebrations.
Tensegrity structures belong to a special category of cable structures. They are defined as systems composed of compression components (struts) inside of a continuum of tension components (cables) in a stable self-stressed state (equilibrium). They are lightweight structures offering higher resistance than other systems of the same weight. Another advantage is their modularity; stable modules can be joined together creating larger tensegrity systems.
From an engineering point of view, the construction of the Tank Street Bridge is a civil engineering achievement. Tensegrity structures are highly complex systems with non-linear behavior. Therefore, the analysis of these structures demands complex computational methods. Additionally, previous tensegrity constructions such as the Rostock tower (Germany) revealed a necessity for high precision. It is also important to mention that there are no widely accepted guidelines for the construction of this kind of structures.
The resulting tensegrity bridge is a network of cables held apart by numerous struts recalling the ropes and spars of sailing ships and boats. Seen from the rivers, struts seem to float over the bridge. They remind sculptures made by the American artist Kenneth Snelson (see “Easy Landing”). Additionally, due to its tensegrity system the bridge offers high transparency with great views over the river to pedestrians. During the night, the bridge will be full of colors. LED lights are chosen to highlight the masts with pastel colors creating a levitating illusion for pedestrians. Different colors will be applied based on the chosen theme creating a contemporary sensation.