News

XBloc Concrete Moulds for the Chathams

For the Chatham Islands, Waitangi Wharf has long been a critical lifeline for the wellbeing of the economy and community. As the Islands’ only cargo-handling facility for incoming supplies and equipment as well as all outgoing ocean freight, Waitangi Wharf is near the end of its structural life and will be completely rebuilt over the next year.

The project is being undertaken by the Memorial Park Alliance, a Joint Venture consisting of Downer NZ, HEB Construction, New Zealand Transport Agency, Tonkin & Taylor and Aecom Consulting NZ Ltd, on behalf of the Department of Internal Affairs.

With improved berthing for larger vessels; the new wharf design will provide the Chatham Islands with improvements in biosecurity, animal welfare and its fishing wharf. A key component in the new design is the 185m long breakwater to be constructed to protect the commercial and fishing wharf. Interlocking blocks; XBloc concrete armour designed and developed by Delta Marine Consultants of the Netherlands, have been selected as proven and cost effective coastal protection and some 4,000 XBlocs will be produced, at the Chatham Island construction site for the project. XBlocs are smaller than traditional tetrapods and are designed to knit together as the breakwater is assembled underwater by use of a 28m long-reach excavator, fitted with underwater cameras giving a live feed to the operator, ensuring accuracy of Xbloc placement.

TRT’s challenge was to fabricate 30 identical concrete moulds out of steel, within extremely tight tolerances, to guarantee every XBloc produced was exactly the same. With the first mould finished and assembled, a test pour was arranged on the factory floor and the dimensions of the XBloc produced were to specification.