Te Whitinga
As part of the Well-Connected Alliance Team, Warren and Mahoney designed Te Whitinga ("the crossing"), formally known as Hendon footbridge, as part of the wider Waterview Connection project. As a large and highly visible component of the overall project, the bridge needed to respond to the aspirations of both the local community and motorists. An extensive consultation process led to the adoption of a fluid sculptural design approach.
The aim of the design was to create a very simple yet beautiful trajectory, with the deck curving three dimensionally through space. The deck, in turn, is supported by a simple but sculpted arch over the highway.
The alignment of the bridge is predicated on the relatively tight site constraints of Hendon Park at the north and the neighbouring Oakley Creek and its catchment on the southern edge of the highway.
The deck plan is generated from three arcs, meeting tangentially and decreasing in diameter as the deck moves south. The simple geometry of the plan is projected up to form a theoretical surface and a constant 7% ramp slope is inscribed onto the surface. This geometrical definition standardises the components required to form the deck while still allowing for a complex and sinuously curved bridge.
As the arch crosses the highway in a near perpendicular relationship and straddles the curving deck underneath obliquely, the non parallel relationship between the deck and the arch results in a complex cable configuration – the surface described by the cables forms a hyperbolic paraboloid.
As a sculptural piece, the bridge is treated as a simple white object – both the concrete deck and steel arch are finished with an arctic white stain and paint respectively. The supporting cables and outriggers from the deck are painted a silver metallic to highlight their highly mechanical function and differentiate them from the deck and arch elements.
The bridge was designed and modelled using parametric 3D software allowing a series of defined geometric relationships to inform all aspects of the bridge design. This approach allows a change to any of the key relationships to be instantly applied throughout the model – from deck profile to cable spacing to handrail geometry.Using a parametric model rather than a traditional digital model allows for iterative design testing and optimisation of the elements.
