This project involved installation of 380m of 1950mmø concrete pipe using the Akkermann 720B open face wheel Tunnel Boring Machine (TBM) at grades of between 2% and 3% with a depth to invert up to 25m.
The site was in the busy Mt Eden commercial district and the main jacking shaft (6mø and 25m depth) was located directly beside the TV3 headquarters.
The project was negotiated and constructed under the collaborative NEC3 format; this was a first for Auckland Council and proved to be beneficial in delivering a challenging engineering solution for the final section of the motions catchment delivery programme.
Work was within a highly built up area and site was very constricted which required liaison with affected local business owners and residents. The limited corridor for pipe route necessitated the construction of the pipeline in a tight 200 metre radius to negotiate around building boundaries.
Shaft construction required the secant piling of the top section of the 28m deep by 8m wide top section and the belling out and construction of a gantry crane to offset the base to alleviate the requirement to relocate a fibre optic cable beside the TV3 headquarters.
Traffic control was of high importance during the retrieval of the TBM on Mt Eden Road.