Wharves at the edge of the world: Physical modelling of zero maintenance breakwaters in remote locations Conference Paper
- Author
- Coghlan, I.R.; Blacka, M.; Shand, T.; Foster, M. Carley, J,
- Year
- 2018
- Journal / Source
- Proceedings of the 7th International Conference on the Application of Physical Modelling in Coastal and Port Engineering and Science
- Pages
- 12
- Summary
- During the design process for a breakwater, construction and maintenance considerations usually play a major part in determining the final geometry of the structure. This is particularly the case in remote locations with limited availability of materials, plant and machinery combined with the tyranny of distance. This paper presents the design development to upgrade existing wharves at two sites within, the Chatham Islands archipelago. These islands are populated by only 600 people, and the wharves on the two inhabited islands, Chatham and Pitt, provide a lifeline for their communities. The physical modelling of both wharves led to a significant reduction of design risks, and constructability improvements. Empirical techniques were found to have mixed results for estimating the stability of concrete primary armour (Xbloc® and Hanbar units) and rock toe armour. Secondary armour stability tests with the breakwater in an “under construction” state also provided insights for construction planning. On Pitt Island, wave overtopping processes were very three-dimensional such that they could only be robustly estimated using the physical model. On the head of both wharves, it was necessary to extend the crown wall normal to the long axis of the breakwater to improve overtopping and armour stability on the leeward side.