Following our success with the Bayswater Viaduct, D&A was invited to be part of the METConnx Alliance design team for the Byford Rail Extension (BRE) Project. The collaboration resulted in the detailed design of the 1.5km Long Approach Viaducts and Elevated Station at Armadale and over 1.4km’s of retaining walls on the approaches, including the single span Wungong Creek Rail Underbridge. Employing the same techniques used for the Bayswater Viaduct, D&A was able to adapt the design to accommodate the rail turnouts to be located on the approach viaducts. The geometry of the bridge was adjusted to splay out the beams and provide additional internal beams with deflection walls where required, still maintaining the modularity of the bridge construction. To define the articulation arrangement for the viaduct, D&A completed an in-depth study of the Track Structure Interaction (TSI) in keeping with current Australian and European Standards. The TSI had to accommodate the inclusion of the turnouts with limiting creep characteristics and the rail expansion joints required by the permanent way designers.
D&A also developed a unique connection detail between the precast columns and piles thus further enhancing constructability. The connection was developed by collaborating closely with the piling and construction teams
to ensure adequate allowance for tolerance has been made.