Turkish contractor Aydiner Constructions has turned to Dynapac to help construct the Mussafah-Abu Dhabi potable water pipeline on the Mussafah Water Transmission Scheme (MWTS) in Abu Dhabi.
The new 32km pipeline will connect the water pumping station at Mussafah and the Delma Street substation in Abu Dhabi, enhancing the UAE capital’s ability to manage its water supply as during the peak summer months.
Aydiner has 16 months to complete the project and has revealed it will utilise a Dynapac CC 900 compaction roller and six LG 160 compaction plates for pipeline compaction duties.
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 378,000m3/day, spans 250km between the Shuweihat desalination plant and Mussafah, carrying water to join the regional supply network serving Sila, Mirfa and Mussafah.
According to Aydiner 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 45t and 60t class excavators for trench excavation, Aydiner are excavating to depths of up to 5m but generally 3m x 3m depending on the surface gradation.
Two ‘bedding-in’ 30cm 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 CC 900 double drum vibratory roller.
Once again ordered through local distributor INMA, the CC 900 is undertaking up to four static passes to meet the specified degree of compaction.
With a drum width of just 900mm, the roller is ideal for small scale compaction duties. The roller features a maximum operating weight of 1.7t and is powered by a Perkins 403D-11 water cooled diesel engine.
Aydiner initially relied on another compaction roller but according to purchasing manager Necati Ozmen, the company quickly recognised that the roller was unable to deliver the performance required.
“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 CC 900 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.”
Aydiner Constructions started pipe laying in October 2010 and completion is anticipated by February 2012 with 9km completed by the end of July 2011.