Abstract
The breakwater at Tristan da Cunha suffered structural damage during heavy seas that battered the island during winter 2010 (June and August). The damage was of such a nature that emergency repairs had to be designed and constructed before the onset of the next winter season. The damage entailed the loss of primary armour units (3.5t dolosse) at the head of the western breakwater exposing the under-layer rock as well as some slight movement of the end section of the crest slab (cap). Further damage to the breakwater head (130m offshore in 6m water depth) was reported one month later; with the crest slab being lifted further by approximately 500mm. The construction methodology during the emergency repair design process, laboratory validation and onsite construction is covered in this manuscript.
Highlights
Model Construction and Dolos Packing The model was constructed for wave directions from 342° and 4°
The bathymetry for the wave direction of 4° was constructed first, after which the bathymetry for waves coming from 342°, which was shallower, was constructed on top of the original bathymetry
The core material and armour of the breakwater was packed simultaneously to best reproduce the original packing method used on Tristan da Cunha
Summary
Aim of the Model Study The main aim was to determine the most effective and stable configuration of the dolosse used for the repair. The limitation was the size of the largest possible dolos units that could be taken to the island at the time, which were halves of a 10 t unit. 10 t dolosse were elected for testing as this was the maximum size of unit that could be transported to site Some remarks on the latter are mentioned based on the design and physical modelling work executed
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
