The city of Poti is located at the mouth of Georgia’s largest river, the Rioni. It has been an important trade centre for centuries. Since the early 19th century, many plans have been developed for the creation of a major sea port. Construction work started in the 1850s on the main breakwater that is still protecting the port today. During its long lifetime, this structure has been maintained by frequently adding 20-60 tons of concrete cubes to the armour layer. Significant settlement of the structure over time has lowered the crest level considerably, resulting in large overtopping volumes and therefore in port-operation downtime. As a result, a rehabilitation project was executed between 2006 and 2008 by Royal Boskalis Westminster N.V. to reduce the downtime caused by overtopping waves.
The project financing was organized by Royal Boskalis Westminster N.V. and, as a result, the project was partly financed by the Dutch export stimulating subsidy for developing countries (ORET) and partly by a soft loan from the ING bank. In total, 50,000 tons of filter material, 10,000 tons of rock and 6,000 Xbloc units were placed.
The cross-section consists of an impermeable wall structure with a homogeneous body of large cubes in front. Hydronamic, the Boskalis in-house engineering consultant, designed -in consultation with DMC, the license holder of Xbloc- an alternative solution. In this new design, the existing cubes on the breakwater slope are covered first with a number of layers of rock before final covering with a single layer of 2 m3 Xbloc armour units.