Water pipeline in Abu Dhabi gets underway

As the population of the UAE’s capital Abu Dhabi approaches 2 million, a new potable water pipeline will meet peak period demand during the summer months.

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

The contract for the Mussafah-Abu Dhabi potable water pipeline (Lot M) on the Mussafah Water Transmission Scheme (MWTS) has been awarded to Turkish contractor Aydiner Constructions with a 16 month completion schedule.

The award follows the successful 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 m3/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 new 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 also 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 a number of oil-related and gas pipelines.

The pipeline will also pass below the Maqtaa creek at a depth of 20 m.  In the event of possible failures and ‘common practise’, the pipeline splits into two 730m pipelines below the creek, re-joining into a single pipe; relying on horizontal directional drilling techniques.

Pipeline trench
Using 45 t and 60 t class excavators for trench excavation, Aydiner are excavating to depths of up to 5 m but generally 3 m x 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 purpose-ordered Dynapac LG 160 plate compactors.

In total six plates were delivered by Dynapac’s local distributor INMA.

The pipe is then surrounded with hand-tampered sand layers using approved backfill with no rock content.  Above the pipe, the backfill is initially compacted in 30 cm layers to be continued using a recently delivered Dynapac CC900 double drum vibratory roller.

Once again ordered through local distributor INMA, the CC900 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 1665 kg and is powered by a Perkins 403D-11 water cooled diesel engine.

Aydiner initially relied on a competitive compaction roller but according to Purchasing Manager Necati Ozmen, the company quickly recognised that the roller provided poor performance.

“In addition,” he continued, “there was virtually no after sales service and spare parts were very expensive.”

“We therefore ordered the Dynapac units and have been very impressed with the back-up provided by the local dealer INMA.”

“The CC900 has quickly become one of our most popular rollers in the Dynapac fleet. Its weight and specification makes it perfect to meet requirements for pipeline projects, road construction and general site duties due to its size and ability to work in confined spaces,” said Kiran , INMA’s Abu Dhabi,

Aydiner Constructions started pipe laying in October 2010 and completion is anticipated by February 2012 with 9 km completed by the end of July 2011.

Dynapac LG160
The LG160 is a compact forward/reverse plate with speed and compaction depth regulated steplessly via hydraulic servo controls.  This ensures smooth plate motion.  It also makes the plate very easy to operate.

The LG160 is proving ideal for backfill duties in pipeline trenches.

For further details please contact:

Lotta Bynke, Dynapac AB
 lotta.bynke@se.atlascopco.com