SIX Dynapac LG 160 plate compactors and a Dynapac CC 900 roller are being put to good use for the construction of a potable water pipeline in Abu Dhabi.

Turkish contractor Aydiner Constructions ordered the machines from local dealer Inma for compaction work on being awarded the Mussafah-Abu Dhabi pipeline project on the Mussafah Water Transmission Scheme (MWTS) in Abu Dhabi.

The Lot M contract was awarded with a 16-month completion schedule.

With a design capacity of 166 litres per day, the new 32-km pipeline will connect the water pumping station at Mussafah and the Delma Street substation in Abu Dhabi.

The award follows the completion of the Shuweihat water transmission scheme, a major initiative combining one of the biggest water pipeline projects undertaken using ductile iron pipes with a desalination plant in the region. The twin pipeline, carrying 378,000 cu m per day, spans 250 km between the Shuweihat desalination plant and Mussafah, carrying water to join the regional supply network serving Sila, Mirfa and Mussafah.

The Lot M contract pipeline features similar ductile iron pipe with a 1.6-m diameter. Its route traverses salt-laden areas with a high water table, requiring extensive dewatering. Initially passing through open desert-type areas, the route includes densely populated urban areas through the city.

Ground conditions have so far not presented any problems for the contractor but, according to Ömer Ali Aydiner, chairman of sister company Aydiner Constructions – Abu Dhabi, unrecorded utilities are posing a particular problem. These include frequent underground electrical lines and water pipelines. The route also runs parallel with oil-related and gas pipelines.

The pipeline will also pass below the Maqtaa creek at a depth of 20 m.  The pipeline splits into two 730-m lines below the creek, rejoining into a single pipe, relying on horizontal directional drilling techniques.

Using 45-tonne and 60-tonne excavators, Aydiner is excavating to depths of up to 5 m but generally 3 m by 3 m depending on the surface gradation.

Two ‘bedding-in’ 30-cm-deep base courses are initially prepared prior to laying the ductile pipes and compacted by the LG 160 plate compactors. The pipe is then surrounded with hand-tampered sand layers using backfill with no rock content.  Above the pipe, the backfill is initially compacted in 30-cm layers to be continued using the CC 900 double-drum vibratory roller.

The CC 900 is undertaking up to four static passes to meet the specified degree of compaction. With a drum width of just 900 mm, the roller is ideal for small-scale compaction duties. The roller features a maximum operating weight of 1,665 kg and is powered by a Perkins 403D-11 water-cooled diesel engine.

Aydiner Constructions started pipe laying in October 2010 and completion is anticipated by February 2012.