Road widening improves traffic

A wide range of equipment is being to used improve Abu Dhabi’s road network. The projects include the construction of a new 80 km road, a number of new access roads and widening existing roads. CW visits the sites to find out more.

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By  Colin Foreman Published  September 26, 2004

Road widening improves traffic|~|40 Product Body.jpg|~||~|AS THE number of vehicles continues to grow in Abu Dhabi, access into and around the industrial centre of Mussafa on the outskirts if the UAE capital is frequently at a standstill. In a bid to alleviate these problems work has started on a number of new access roads. One of the new roads is Contract 953/3 that will principally provide new improved access between Mussafa and Mohd Bin Zayed City. Almost 80 km of new highway is being prepared and paved by main contractor Abu Dhabi Gen. Transport Co (GTC), in a 24-month contract with a completion date of September 2004. Up to 20 km will be new dual carriageway, with a 12 m road width 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 relied on a fleet of Dynapac compaction and pneumatically tyred rollers; all supplied by local distributor INMA. Using a combination of Dynapac CC222 vibratory tandem rollers and CP271 pneumatic tyred rollers to achieve an even smoother finish, GTC are able to accomplish the 98% Mashall specified for the asphalt wearing course. The new road comprises a 20 cm asphalt thickness and 8 cm side median on the dual carriageway and 19 cm on the sector roads. 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. Another road project is a six-lane road-widening project on Mussafa road itself. Hilalco has now handed over the project on schedule. The contract also included a 400 m underpass and installation of a 100 m-long steel bridge over a waterway channel. “Whilst it may not be the biggest job in Abu Dhabi, it has to be 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, Hilalco. Abu Dhabi contractor Hilal Bil Badi & Partners Contracting Co (Hilalco) has completed its major road-widening project on the Mussafa Highway on schedule, handing over to the Municipality Highways Department. The project, which included a 400 m-long underpass and the installation of a 100 m steel bridge over the channel, doubled the number of lanes from three to six in each direction over 600 m – intended to ease congestion during peak times into the industrial centre of Mussafa. In total, the project included 2.1 km of widening road 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 on 23rd November, 2002, relying on a fleet of Dynapac compaction rollers, including two 8 t class CC222 and a 11 t class CC422 vibratory articulated tandem rollers and CP271 and CP221 pneumatic tyre rollers. The newly completed six-lane dual highway also includes 3 m outer and inner hard shoulders. Hilalco initially prepared three base grades at 10 cm, 9 cm and 6 cm respectively before capping with a 6 cm asphalt-wearing course. According to Zachariou, 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. Prior to installation of the bridge, Hilalco carried out piling works with sixteen 1 m 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 and the steel deck. 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. 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, 1 m thick walls, sitting on a 1 m reinforced concrete base and 1 m thick concrete slab, the underpass is 22.75 m wide. Cast in-situ concrete and waterproofed from outside and downside, the underpass is topped with a 1 m thick slab and beams supporting the highway. Throughout construction of the underpass, due to the close proximity of the adjacent waterway and low watertable, constant dewatering was necessary. Once completed, the Dynapac rollers were being used once again for compaction of the 5 cm asphalt footpaths on both sides of the highway leading to the bridge. Hilalco also relied on a fleet of Atlas Copco portable air compressors to provide 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. Featuring an actual free-air flow of 185 l/s at 7 bar, the XA186 is powered by a 4-cylinder Deutz diesel engine rated at 90 kW at 2400 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. The Atlas Copco compressors and Dynapac rollers were ordered by Hilalco through local distributor INMA who is also responsible for providing aftersales and spare parts back-up. ||**||

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