Proposed layout for the Amwaj project.
Geotube technology comes to the Gulf
Geotube containment technology will be introduced for the first time in the Arabian Gulf in the reclamation of islands at a $1 billion resort project in Bahrain.
01 MAY 2001
TC Mirafi of the US, a world leader in geocontainment solutions, has been awarded a contract to supply and install its geotube sand containment structures in the construction of a $1 billion tourist island project off the coast of Bahrain.
The contract was signed with the promoter Ossis Property Developers which is building the Amwaj Islands, northeast of Muharraq.
This is the first such use of the geotube containment technology in the Gulf region, according to Ossis.
When completed, Amwaj Islands will be one of the most luxurious resort communities in the Gulf, with a luxurious shoreline, lagoon residential villas and condominiums, a five-star hotel, marinas and an amusement park.
The 3 million sq m project will consist of a cluster of islands connected to each other with bridges and canals reminiscent of Venice. The entire complex will be located 2 km offshore and will be connected to the mainland via a causeway.
The geotubes will be used to confine sand that will be dredged to form the islands and causeway platforms and thereby prevent any damage to the surrounding marine environment.
The geotube containment technology has been developed by Royal Ten Cate of the Netherlands and is manufactured and marketed by two of its divisions, TC Mirafi and TC Nicolon.
Both companies will have technicians assisting Ossis with construction start-up.
The geotubes are fabricated in sections of high-strength woven polypropylene industrial synthetic textiles with special high-strength seaming techniques to resist pressure when they are pumped with sand. Each section weighs approximately 2,500 kg.
When installed at the site and filled with sand, each section will be 100 m long, 2.6 m high, 5 m wide and weigh more than 1,100 tonnes. Each section will be linked end to end to form the perimeter containment and erosion protection for the new islands and causeway.
The first phase of the project, scheduled for completion in 20 months, covers reclamation work and development of infrastructure. The second phase will involve development of the tourist facilities.
TC Mirafi conducted a seminar in Bahrain last month on design methodology, application techniques and related case histories. The seminar, which was attended by around 150 engineers and prospective investors in the project, was hosted by Ossis at the Bahrain Society of Engineers headquarters in Juffair. Geotube technology expert Dr Jack Fowler was among the panel of experts at the seminar.
Addressing the seminar, Tom Stephens, vice president, Miratech Division of TC Mirafi, said: "TC Mirafi offers design assistance, technical assistance and specialty fabrication.
"We custom-make our products to suit the requirements as well as environmental conditions. In fact for the Amwaj project, two of our engineers will be on-site to provide assistance.''
The company offers more than 100 different geosynthetic products - produced from polypropylene or polyester - which can be classified into four major categories:
Highlighting some of the advantages, Stephens said the system offers rapid construction and is environment-friendly and cost-effective.
"Sections of up to 100 m can be completed every day,'' he said. ''The system has a minimum impact on the environment while providing a beneficial use for dredge material.''
He continued: "This technology may be new to the region but has been used successfully around the world for well over two decades.''
He cited a wide range of applications, including the Boardwalk in Atlantic City, the Red Crossing in the US and a recent project at Bondi Beach in Sydney, Australia, where it was used in the construction of the temporary stadium for the Olympics.
"Mirafi geosynthetics are used as integral components in the design and construction of a variety of marine and hydraulic engineering structures such as revetments, breakwaters, levies and marine spoil containment structures. The materials used are easy to install beneath the water surface, in difficult conditions, and once in place provide continued performance.
"In marine applications, the geosynthetics serving as containment devices enable placement of fill and spoil materials on the seabed in an orderly and controlled manner. They prevent the loss of contained fill and spoil material. Submerged structures, such as breakwaters, groynes and spoil-containment areas can be cost-effectively constructed using this technique.
"The geosynthetic can act as a filter underneath revetments to prevent the erosion of soil. The armour protection on top of Mirafi can be a wide range of materials such as rock, gabions and mattresses, concrete pattern-placed units, etc. Applications range from river bank protection to coastal defence works.
"As a filter at the base of rubble-mound breakwaters, the geosynthetic prevents the erosion of the foundation soil through the granular layers in the breakwater.
In some instances, the geosynthetic may also be required to reinforce the base of the breakwater when it is constructed on soft foundation soils.
"Mirafi's extensive product range is suited to a variety of applications for landfill and waste-containment structures. Examples include protection layers for geomembrane liners, veneer reinforcement for the enhancement of material interface properties, reinforcement to steepen landfill containment slopes, support liner systems constructed over compressible foundations, or reclaim tailings and other waste lagoons, and drainage for gas and liquid removal.
"The company's geogrids and high-strength geotextiles provide tensile resistance to the soil, thus enhancing its shear strength characteristics. This enables walls, slopes and embankments to be constructed cost-effectively and quickly,'' he explained.
