MAYPOLE CREEK STORMWATER UPGRADE

The installation of the innovative Uni-culverts posed technical complexities owed to this product being the first of its kind used within Tasmania in a horizontal application and at such a long length. Both DCS and Hudson Civil were unfamiliar with the use of this new system and together, the project team carefully planned, designed and developed various methods to lift and install these large precast products within the tight construction tolerances for line and level.

The site location provided additional challenges throughout the process of the construction works. This site was originally a creek, which had been filled during a previous development. This natural watercourse provided a technical complexity in providing a safe and reliable stormwater bypass system to maintain a highly workable bedding for the Uni-culvert excavation and placement. The bypass system needed to fit within the needs of the local community and environment, hence a diesel generator pumping system could not be utilised. The DCS management team together with Netco Pumps developed a three-phase, single staged suction pump with remote access to provide low to medium flow stormwater bypass pumping arrangement.

Another site complexity came from the temporary engineering works required to support the existing heritage building and retaining walls, whilst excavating further below the building foundation levels. The deepest excavation was 4.5m below the existing surface level of the adjacent building. Whilst a design was nominated, the DCS team identified that this system was not constructible, nor could it provide the lateral restraint required to support the deep excavation. With the assistance of Scherzic Ground Investigations, DCS developed and installed a soldier pile shoring system strong enough to support the building and protect the DCS site personnel during the excavation and placement of the Uni-culvert system.