Bridges

The Flinders Link Project incorporates the design of 650 m rail extension of the Tonsley Rail Line to the Flinders Medical Centre and University precinct south of Adelaide CBD, comprising of a 430 m long viaduct, a new station and an elevated walkway. The primary purpose of the Flinders Link Project is to:

1. Connect the Flinders Precinct to the rail network;
2. Improve public transport passenger access to the Flinders Precinct;
3. Facilitate an interchange between bus and train services passengers;
4. Improve pedestrian & cycling connectivity between the Flinders Precinct, Laffers Triangle & Tonsley development; and
5. Enable and integrate with the future development of the Flinders Precinct.

This paper will focus on the technical design of the viaduct for a single ballastless track rail extension incorporating a shared use path (SUP) for the pedestrian and cyclist connection between Sturt Road and Flinders Station.

The key challenges and innovation associated with the viaduct design include site constraints resulting to a horizontal sweeping curvature of 237 m radius, the 50 m main span over the lowered Southern Expressway and the resulting taller piled foundation that needed to be integrated into the expressway retaining walls, and the elimination of rail expansion joints for the entire track extension reducing maintenance costs and operational risks. The adoption of simply supported twin steel box girders with precast concrete ‘biscuit’ permanent formwork panels combined with simple and aesthetically profiled pier have significantly contributed to the speed of construction particularly the inclusion of 3D reinforcement modelling for the pier head.

The paper will also present the rail-structure interaction analysis which informed the bridge form and pier configuration to achieve no rail expansion joints including the dynamic behaviour assessment considering pedestrians and passenger’s comfort.