Stepping on the gas

As the first phase of Ras Laffan Industrial City’s ambitious gas port expansion scheme nears handover, Roger Lindley marvels at the size of the job and the precision it demanded

Specialist marine and coastal engineering plant hire company Abeko is close to completing the first-phase expansion of the Qatari LNG port – already home to two of the world’s largest natural gas terminals – in preparation for handing the site over to its client, Van Oord, for fitting out.

Abeko won the contract to provide the machinery and operators that Van Oord needs to build 22.5km of causeways and breakwaters. Van Oord is already undertaking final surveys and, in conjunction with the Abeko team, is carrying out any remedial work needed to ensure the constructions conform to design specifications. Whether using land-based equipment or working at sea, these operations call for precision to avoid disturbing material already in place. To that end, an O&K RH90C excavator mounted on board Abeko Server 1 is helping with final underwater profiling of the breakwaters.

As the first phase nears completion, some idea of the sheer volume of material deployed can be gained from the kilometres of structures standing several metres above the water line.

Over 10.6M tonnes of local rock, together with a further 4.2M tonnes imported from the UAE, have been put in place, either by side-dump barges or by dump trucks. The prefabrication yard’s swallowed up more than 1M m³ of concrete to make the 185,000 precast concrete antifers and 36,000 concrete Accropodes that formed the armour layer for the breakwaters. The antifers come in three sizes – 1.5m³, 3m³ and 3.5m³ – while the Accropodes range from 3m³ to 5m³.

The rock and precast concrete elements were used to profile and protect the land reclaimed by placing more than 20M m³ of dredged limestone and 25M m³ of offshore sand. And well over 900,000m3 of geotextiles have been incorporated into the structures.

The causeways and breakwaters are topped by 3.4m-high crown walls and reinforced road slabs that typically measure 50m wide and 2.15m deep, for which more than 170,000m³ of concrete was poured.

Non-Stop

Throughout the project, the contractors have used 45 heavy-duty excavators and high-capacity crawler cranes, 40 rigid and articulated dump trucks, 20 wheel loaders and other support equipment. Work on the project continued non-stop, 24 hours a day, seven days a week and, at its peak, kept more than 700 Van Oord and Abeko personnel busy.

All the works are designed to very demanding requirements. Th ...