A number of roads are being built or widened to ease traffic congestion during peak times into the industrial centre of Mussafa, Abu Dhabi.

These include a dual six-lane highway-widening project on Mussafa Road – which has just been completed – and a new highway linking Mussafa with other areas of the emirate, which is scheduled for handover next month.
Abu Dhabi General Transport Company (GTC) is gearing up to hand over almost 80 km of the newly-prepared and paved highway this September.
Meanwhile, Abu Dhabi contractor Hilal Bil Badi and Partners Contracting Company (Hilalco)  has successfully completed work on the dual six-lane highway-widening project, and the road was handed over to the Municipality Highways Department last month. “Although it may not be the biggest job in Abu Dhabi, it has been the most interesting – featuring virtually every discipline of civil engineering, including a major underpass, a new bridge, major lane widening, waterproofing and dewatering,” said Nicholas Zachariou, project engineer for Hilalco.
The project, which included a 400 m-long underpass and the installation of a 100 m steel bridge over a channel, has doubled the number of lanes from three to six in each direction over 600 m – and is expected to ease congestion during peak times into the industrial centre of Mussafa.
In total, the project included 2.1 km of road widening plus exit and entry loop roads.
The underpass and steel bridge directly link Officers City and Two Bridges City on the outskirts of the UAE capital, considerably reducing the travel times between both cities.
Hilalco started work on the 19-month contract in November 2002, relying on a fleet of Dynapac compaction rollers, including two 18-tonne class CC222 and a 28-tonne class CC422 vibratory articulated tandem roller and CP271 and CP221 pneumatic-tyred rollers.The newly-completed six-lane dual highway also includes three-metre outer and inner hard shoulders.
Elaborating on the project, Zachariou says: “We initially prepared three base grades at 10 cm, 9 cm and 6 cm respectively before capping with a 6 cm asphalt wearing course.
“The first passes were made with the Dynapac CC222 using both vibratory and static passes before completing compaction with the heavier CC422 roller.
“The pneumatic-tyred rollers followed the compaction units to ensure a smooth surface.

Steel bridge
Prior to installation of the bridge, Hilalco carried out piling works with 16 one-metre diameter piles bored on both sides of the waterway to depths of up to 22 m.
Fabricated off site, the steel bridge was towed along the waterway and hydraulically ‘jacked’ into position in three segments.
The centre segment was 60 m long with the two end segments each 20 m. Once installed, steel chevrons were welded to the deck in order to prevent the asphalt wearing course ‘sliding’ as a result of the high ambient temperatures.
To further improve the preparation and to ensure a rough bonding with the steel deck and asphalt, a 3 mm-thick slurry material and 2.5 m compacted sand course covered the chevrons.
A 5 cm wearing course was paved using the Dynapac rollers but with a reduced vibration and more passes, he explains.

Underpass
The underpass beneath the widened six-lane highway and leading directly to the new bridge was excavated and cast in-situ.
Featuring 6.5 m high, one-metre-thick walls, sitting on a metre of reinforced concrete base and a one-metre thick concrete slab, the underpass is 22.75 m wide. Built using cast in-situ concrete and waterproofed from outside and downside, the underpass is topped with a one-metre thick slab and beams supporting the highway.
“Throughout construction of the underpass, due to the close proximity of the adjacent waterway and low water table, constant dewatering was necessary.
“Once completed, the Dynapac rollers were being used once again for compaction of the five cm asphalt footpaths on both sides of the highway leading to the bridge.

Airpower
A fleet of Atlas Copco portable air compressors provided Hilalco enough airpower throughout the various elements of construction. Two XA186 compressors, for example, have actively been used, particularly for air tools, during installation of the steel bridge and concrete vibrators, says Zachariou.
Featuring an actual free-air flow of 185 litres/second at 7 bar, the XA186 is powered by a four-cylinder Deutz diesel engine rated at 90 kW at 2,400 r/min.
The compressors were also used for cleaning surfaces of the underpass walls allowing them to be finished with mosaic tiles depicting local scenes.
Hilalco ordered the Atlas Copco compressors and Dynapac rollers through local distributor Inma who is also responsible for providing after-sales and spare parts back-up.

GTC’s involvement
The 24-month project being implemented by GTC, involves paving a new road of up to 20 km having a new dual carriageway, with a 12 m-wide road and median, whilst some 60 km will provide sector roads to provide internal links for new neighbourhoods.
Throughout construction of the new highway, GTC has also relied on a fleet of Dynapac compaction and pneumatically tyred rollers – all supplied by Inma.
The new road comprises a 20 cm-thick layer of asphalt and 8 cm side median on the dual carriageway. Using a combination of Dynapac CC222 vibratory tandem rollers and CP271 pneumatic tyred rollers to achieve an even smoother finish, GTC has been able to accomplish the 98 per cent Mod Proctor specified for the asphalt-wearing course.
The fleet of Dynapacs is working full steam to complete compaction duties ahead of the completion date.
Throughout compaction, GTC made five to six static and vibratory passes with the CC222 tandem rollers and six to eight with the CP271 over a pass distance of approximately 20 m, he adds.
“As the number of vehicles continues to grow in Abu Dhabi, access into and around the industrial centre of Mussafa on the outskirts of the UAE capital is frequently at a standstill. Work started on the project in a bid to alleviate these problems on a number of new access roads, improving the link with cities such as Mohd bin Zayed City,” says a spokesman for Dynapac.