Gungahlin Drive Extension Stage 2 – Duplication of Bridges Ginninderra to Ellenborough Street

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Project Location: North Lyneham/Kaleen

Client: ACT Procurement Solutions
Client’s Representative: Jock Mclean
Superintendent: GHD
Superintendent’s Representative: Geoff Gardner
Project Start Date: January 2010

Description:

This project comprises the construction of two bridges and an archway to allow duplication of Gungahlin Drive  southbound carriage way in the future.

Scope of work:

  • Modification and installation of reinforced earth walls 140m²
  • Duplication of Ginninderra Dr bridge – 40m across a single span
  • Duplication of Ellenborough St bridge – 20m across a single span
  • Extension of Lyneham ridge bebo – 8 interlinking arches 1.8m wide.

Discussion:

As with any construction adjacent to major roads the traffic posed a significant challenge. Strategic traffic management plans were devised to formulate traffic flow around construction vehicles entering and exiting the sites. In addition to this, major traffic closures including the shutdown of Ginninderra Dr and Ellenborough St for the girder installation had to be coordinated early in the piece to ensure no clashes with surrounding venues.

Guideline ACT being familiar with the past works on the Gungahlin Drive Extension and in particular the bridge details were able to offer simplified methods to produce a time saving a cost efficient project.

Retaining wall modification was a steady and tedious process, having to brace, excavate and remove the reinforced earth panels in a manner not to disturb any of the surrounding earth straps or offset any remaining panels.

Due to the substantial size of the girders spanning the width of Ginninderra Dr (40m), 1.8m deep and approximately 80 tonnes, careful planning of the positioning and movement were prepared through the lift plan. Making allowances for the cranes capacity ensuring a single day lift and the fact that only three of the six girders could be transported per day had to be considered for thier safe and swift installation. Ellenborough St required simular attention to details for the 21 metre long, 29 tonne girders.

Lyneham ridge bebo arch was extended by 14m with a series of 8 interlinked concrete arches. These arches were then backfilled strategically while the installation of a reinforced soil earth wall was installed in the backfill process.