Marsden Cove , Northland NZ AceGrid

Project Background

Marsden Cove is a unique and comprehensively planned marine village found just within the mouth of Whangarei Harbour, offering a waterfront lifestyle that is second to none. Complete with a world-class 230 berth marina at its centre, and a surrounding residential development comprising impressive waterfront and near-waterfront sections, the popularity of Marsden Cove is increasing. With more lots recently released, the area is rapidly becoming Northlands premier boating destination and Whangarei district’s most desirable neighbourhood.

The initial stage included a 230-berth marina and commercial centre, more than 60 exclusive canal-front sections and 40 non-canal sections facing cul-de-sacs and connecting streets. In successive stages, another 150 sections have been released.

Stage 5 development was completed in December 2019 by our client Hopper Construction, continuing this unique canalside construction project.

Problem

With the development featuring a man-made system of canals, ground improvement and the reinforcement of building platforms was a key concern for this project.  A stable subgrade with sufficient bearing capacity was required: as often happens, the required bearing capacity on subgrades cannot be achieved, such that additional measures have to be undertaken.  As an economic solution to improve the subgrade strength, and as an alternative to using a greater thickness of platform material, the installation of geosynthetics for reinforcement, filtration and separation were adopted.

Solution

Geosynthetics are generally placed between the subgrade and the material forming the working platform. In this circumstance, Global Synthetics was able to supply AceGrid ® GG400 which was further tailored and manufactured in special lengths to avoid wastage as the joints were not able to be joined.  The polyester yarns used for producing ACEGrid® GG geogrids have very high tenacity with premium quality. Additionally, with the expertise of manufacturing geogrid, the tensile strength of the geogrids at low strain is developed at large. Thus, such a high strength geogrid as GG400 has very low elongation and excellent anti-creep performance.

Results

Hopper Construction was extremely happy with the product arriving on time to meet a tight deadline.

The products proved to be very easy to handle thanks to the customised lengths and offered superior performance to the geogrid previously utilised.

Also, by using the high strength AceGrid product coupled with on-site representation from Global Synthetics, this solution proved to be invaluable. Global’s Laurie Vercoe provided layout and installation assistance, and ACEGrid® provided an effortless and cost-effective countermeasure for land preparation and development.