Corban Reserve Stormwater Upgrade
A new larger-diameter pipeline installed using a 2100 mm diameter MTBM
Completed in 2024, the new 713-metre-long stormwater pipeline under Border Road in Waitākere, Auckland allows for future growth and protects and enhances local streams.
The contractor sought a methodology and construction programme that considered the local community and ecology. Shaft locations were chosen to reduce the number of sites required and their size was developed to limit noise and vibration impacts.
Challenges. The stormwater network in the areas was already struggling with heavy rain. Auckland Anniversary Weekend floods in 2023 impacted the project and its neighbours–clearly demonstrating the need for a new pipeline.
how did we optimise, earlier?
Working closely with McConnell Dowell during the tender phase, we minimised the risk of undertaking a MTBM operation with low headroom. This allowed the contractor to confidently propose their preferred methodology of a single 713m long thrust.
We undertook advanced, fully-coupled finite element analysis to more accurately assess the predicted settlement, groundwater drawdown and all of the temporary works associated with the mTBM operation.
Use of innovative analysis allowed us to assess the service crane as additional overburden at the launch shaft. This minimised the size of the thrust block required.
