|Client:||Joint venture between Murray & Roberts Marine and Overseas AST|
|Location:||Abu Dhabi. EMEA|
The AI Raha Beach Development project in Abu Dhabi comprised the construction of 13,4km of concrete sea wall protection to form a series of artificial islands. Together with the reclamation work this provided prime new development land for the residential and commercial buildings being planned for this up-market waterfront precinct. The US$200 million contract was awarded to DRA Global on a design and construct basis as a joint venture between Murray & Roberts Marine and Overseas AST.
The sea walls were formed using 6m high precast reinforced concrete L-wall units, each weighing 50 tons. A layer of soft material varying in thickness between 1m and 2m covered the existing seabed, and ground improvement was therefore required. The walls were consequently founded on a grid of 1,0m diameter stone columns extending down to firmer material, overlain by a 1,3m thick rock layer.
A crushed stone bed layer was placed over the rock layer, and the top surface was leveled using a purpose made stone spreader operated by divers. The units were placed with a nominal gap of 30mm between units. Grout socks placed in recesses in the walls of the units formed the joint seal between successive units.
About 6,000 precast units were cast encompassing 51 different types, and a total of 310,000 tons of concrete and 14,000 tons of reinforcement were used. DRA Global designed a special lifting tool for moving and transporting the units, with the emphasis on safety and ease of use as each unit had to be handled up to 5 times from casting to final placing.