For a complex pipeline protection project, Maccaferri’s Gabions were used in order to secure the transportation asset, while respecting the environment.
The natural environment of the Mauritius islands is a unique scenario. Here, Maccaferri was asked to provide protection for pipelines sitting at the bottom of the Baie Du Tombeau at various depths (5 to 10 meters).
The pipelines were exposed to serious hydrodynamic stress caused by wave motion, and were consequently undermined and potentially risking collapse with catastrophic consequences for the residents.
The protection systems needed to face a wave height of 13m, wave periods of 14s and a return period of 1 in 100 years. A further consideration for the solution was the underwater installation technique.
For such a complex scenario, Maccaferri opted for a set of pre-filled bags of stone, placed beneath and around the pipes, and gabions placed over the new rock platform.
Gabion units were filled off-site. The weight was approximately 1,5 tons each. Additional reinforcing steel rods were threaded along the selvedge wire of each filled unit to ease repeated lifting operations.
This gabions structure was then lifted and placed onto a floating barge and lowered into the water to the correct location. Divers assisted during the positioning of the gabions over the pipelines.
Gabions are, notably, useful instruments bringing several benefits. Plus, pre-filling the gabions shortened assembly time, as the filling process was not performed underwater. Finally, after the installation, marine life colonised both the wire mesh and the gabion rocks, making the whole installation eco-friendly and biologically sustainable.
More details about this case history are available here.
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