SP68 Pump Station

Project Scope

Doval was engaged to carry out the excavation and construction of the 14m dia and 25m deep SP68 pump station in Robina to serve as the replacement pump station for approximately 10 aging pump stations that were to be decommissioned.

To control the accuracy of the descent of the caisson, Doval utilised a caisson construction methodology incorporating a jacking system.

This required installation of 6, 100t hydraulic jacks around the caisson supported by a 2m x 2m x 50m concrete ringbeam which provided the kentledge required for the jacks.

Doval identified a high water table which was managed throughout the installation as well as 24/7 maintenance of 5 dewatering wells around the caisson.

After identifying contaminants in the water, Doval installed a CSM cut-off wall around the outside of the dewatering wells and direct injection of the dewatering into the sewer system.

Following on, 45 rock anchors were installed in the caisson base where a 2m high floor was constructed.

The caisson was then bisected with a 1.1m wide dividing wall with jump forms for the full height of the caisson.

The coordination of the connection of both the rising main contractor and gravity main contractor was critical to ensuring the overall program for the works was delivered.

The project was plagued with problems from the outset and delays seemed to regularly set back the final delivery date of the project, however, through the expertise of the entire project team, the milestone dates were successfully reached and the works satisfactorily completed.

Key Staff

Andrew Bateman – Construction Manager

Stephen Beck - Project Manager

Andrew Duncan - Site Supervisor

Cobby Roles - Site Supervisor

Aaron Armstrong - Site Supervisor

Challenges

The project was brought to a stand still only one month after commencement of construction due to the discovery of extreme levels of contaminants in the ground water

The first grout curtain installed by the client failed during the caisson construction and the project was brought to a stand still until a solution could be found

Caisson depth of 25m and 24hr dewatering made construction logistics complex

• Project:

  Construction of a Sewerage Pump Station

• Location:

  Gold Coast, Qld

• Client:

  BMP Alliance

• Practical Completion:

  December 2008

• Contract Period:

  26 Months

• Contract Value:

  $6.8 million