An Exploration: Rock Versus Newer Solutions
It is in human nature to be innovative in all aspects of life. In the construction world and marine works in particular, some of the maritime structures are built from natural materials, such as rock. This means that rock material will ideally have to be found from a nearby quarry, in order to lower project costs. However in some cases, it is hard to find a quarry nearby, forcing us to use rock material from far away, which can have a negative impact on the costs of the project.
In order to be innovative and find solutions to fully or partially replace rock material, new materials have been adopted to build coastal protection structures, such as breakwaters, revetments and beach toes. One example is Geosynthetic Sand Containers or Geobags/Geotubes. GSCs have only been in the market for a few years, but are already being used worldwide.
Depending on the project specs and requirements, Geobags can be used as temporary or permanent structures. Geobags can be built in different dimensions, again depending on project requirements and project environmental data.
Geobags are ideal as a temporary revetment structure, in order to prevent erosion of the site during construction stage. As the bags are filled with sand material, that sand can later be used to profile the beach area once the project is completed. Using rock revetment in this case will not be cost-effective, as to remove temporary rock revetment the same machinery that was used to construct it will be needed. On top of this, used/removed rock material will need to be disposed of, while with geobags, sand inside the bags can be used to make a nice beach on that temporary revetment location.
Ecocoast has been involved in one project in Dubai that had such requirements. As aggressive erosion on the beach side of an Island had negatively impacted the stability of site offices, car parks and access roads, a temporary structure had to be built, to reduce erosion and stabilise the site area until all construction works on the Island were done.
Ecocoast installed a temporary protection wall, consisting of sand-filled geobags. As one of the end goals was to have a nice beach on one of the sides of the Island, the sand from the bags was used to profile the beach. Meaning, beach material that was already delivered to the site could in this case be used as temporary coastal protection.
Written by Nikola Zutic, Technical Engineer at Ecocoast Contracting LLC