The works were conducted in three parts;
- Initial Service Proving and Design Validation
- Bored Pier Installation, Excavation and Pipeline Inspection
- T15 Validation Excavations
In preparation for the installation of the CTM as well as Micro Tunneling of the major Princess Highway, significant service proving and design validation was conducted to ensure adequate room for the anticipated design of the CTM as well as clearances for the Micro Tunneling. Once all services were proved NAP and APA worked closely to validate the existing design and develop a methodology for submission to the relevant regulators and authorities.
Service proving, pipeline excavation and integrity testing of the anticipated ISW location in the Princess Highway center median was also conducted to conform the location was suitable for future welds.
Following service proving and validation, a bored pier design was developed in conjunction with APA and NAP in alignment with the requirements of the methodology and the nature of the excavation due to its proximity to third party assets and being located in the center median strip of Princess Highway.
Once the design was approved National Australian Pipelines commenced bored pier installation including strip footings and shotcrete of sidewalls. Excavation was completed in stages to final depth of 4 meters and scaffold access was constructed to maintain access throughout the pipeline NDT and ISW works.
All works were completed within NAP managed traffic management plans implemented daily for speed restrictions and construction access on Princess Highway.
Following completion of NDT and ISW checks the concrete structure was backfilled in compliance with APA and DoT requirements and the area was remediated / reseeded.
Further validation digs were conducted on the T15 pipeline in preparation for future robotic crawler ILI inspection with NDT and heat sync completed at the location of required fittings to verify the locations suitability. Once all checks were completed the information was provided to APA to inform the future works and each location was remediated to council requirements.
