Telstra Cable Crossing Design - Darwin Harbour

Atteris delivered a cost-effective design to Telstra for a submarine telecommunication cable crossing over several major gas pipelines in Darwin Harbour. The design used the maximum horizontal bending radius of the telecommunication cable and the most optimum seabed conditions to cross the pipelines. Crossing locations were identified where there was sufficient quarry rock cover. This provided the necessary separation distance between the cable and each pipeline without the need to prepare the crossing locations with additional quarry rock or concrete mattresses. The work performed by Atteris in close communication with Telstra and the pipeline operators resulted in an optimised, feasible, and cost-effective route for the cable.

Telstra needed to install a new telecommunication cable across Darwin Harbour, between Mandorah and the city of Darwin. The cable would need to cross two existing major gas pipelines and the route of a proposed new gas pipeline. All three pipelines run parallel in Darwin Harbour and are approximately 100 m apart. The two existing pipelines are covered in a protective layer of quarry rock; however, the rock cover is very limited in places. The new gas pipeline is installed after cable installation. Therefore, this pipeline crosses the Telstra cable. Atteris performed the design and the engineering interface between Telstra and each of the pipeline operators. Separation distances were agreed and proposed crossing locations were reviewed by all parties. Telstra liaised with the cable installation contractor regarding proposed routes and bending radii.