Site Visit: Al Maryah Island
Atkins talks about the completion of Phase 1
Atkins carried out the design and supervision of the Phase 1 roads and bridges on Al Maryah Island, formerly Sowwah Island, in Abu Dhabi. CW speaks to Eng. Taysir Al Muti about the consultant’s ongoing involvement and the plans for Phase 2. By Gerhard Hope
Having already designed and supervised four bridges at Al Maryah Island, consultant Atkins is confident of having the leading edge over its main competitors AECOM and Parsons Brinckerhoff for the four bridges of Phase 2, comprising two signature bridges, a cable-stayed bridge and a bowstring arch bridge. This package is worth an estimated $51.3m.
Al Maryah itself is essentially a 500m-long island about 100m off the main Abu Dhabi island, and is slowly being transformed into the capital’s new central business district. This has been done through the extraordinary engineering feat of elevating 57ha of the island to 14m above sea level.
At podium level, 4.5km of roads, a link to the Abu Dhabi Metro and a light rail line will provide access to the mega project, while a 12km road network underneath will provide service and back-of-house access. The mega project is being developed in three main phases, with Phase 1 commencing in May 2008 and now largely completed.
“The current progress is that the infrastructure is 100% complete. All that remains to be done is some improvement to the junction hub to improve the traffic flow to and from the island,” Taysir Al Muti, head of infrastructure sites supervision, Middle East and India, Atkins, tells CW during a site visit to Al Maryah Island.
The initial phase has also encompassed the iconic Sowwah Square, which will ultimately be the new home of the Abu Dhabi Stock Exchange.
Al Muti says that four bridges, as well as all utilities, together with the tiered road network, as well as the island’s sea wall, have all already been built. The podium-level roads and public realm are all supported on reinforced concrete bridges and elevated structures.
Precast beams were used where possible in order to ensure quality and fast-track construction, but a lot of concrete was also cast on-site under the watchful eyes of Atkins engineers, who have been with the mega project since its inception.
“It is a lot of concrete,” Al Muti says matter-of-factly. A total of 400,000m3 of concrete was poured on-site. In addition, 8,000m3 of precast concrete was used for the 3,700 I-beams that were required, of which 20% were post-tensioned.
All of this sits on 1,420 piles up to 30m deep. A total of 150,000m2 of bridge decking was required. There are 57 continuous slab-deck spans along Road P1 and P3.
It is difficult to imagine Al Maryah Island before it was developed. “It has been an experience to see it progress,” says Al Muti, who has been with the project since 2008. “There was nothing here at the beginning, only a single steel bridge to Abu Dhabi, and that was restricted to Navy use.”
Atkins’ scope of work on Phase 1 was the design and supervision of all roads and bridges of the two-level road network, with a service-road network at grade level and the main trafficked roads elevated to provide access to buildings at podium level.
Thus it is easy to under-estimate the sheer scale and complexity of this mega project, which makes maximum use of its constrained site. The end result is an elegant and sophisticated example of engineering and planning excellence.
The mega project has also necessitated close cooperation with main contractor Al Naboodah, with which Atkins has since worked with on projects in Dubai. Al Muti comments that it is has been a highly successful contractor-consultant relationship, on a flagship project that has been a landmark for the entire professional team.
The design of the elevated roadways and marine bridge crossings incorporated corridors for light-rail transportation, pedestrian walkways, public realm landscaping and a major underground metro and high-speed rail station, “thus creating a sustainable integrated transport system for the development,” explains Al Muti.
In total there will be 13 new bridges connecting Al Maryah to Abu Dhabi, Reem Island and Mina Zayed. Podium-level bridges, elevated structures and ramps within Phase 1 amount to 4.5km, with 2km of podium-level LRT corridor bridges and elevated structures. The service-road network is about 7km long.
Al Muti explains that about 2.16km of main utility tunnels are buried along the service-level roads in Phase 1. In addition, the overall length of the Bridge 01 and Ramp R1 service troughs and utility tunnel galleries is 430m.
The main underground utility tunnels at service level comprise reinforced concrete box-shaped tunnels, with internal dimensions of 4.8m by 5m. The bottom floor of the utility tunnel is about 6m below ground level. In addition, a quay wall has been built around the entire perimeter of the tunnel.
The podium-level roads and public realm are supported on bridges and elevated structures, with direct pedestrian linkage between the two levels via vertical transport links, namely six fire-access steel stairways and five steel pedestrian structures, which also connect between adjacent plot developments such as Cleveland Clinic.
Al Muti says the project has been challenging from an engineering point of view due to the constrained site.
“The edge of the boundary wall means there is no leeway or little tolerance. This has required careful planning and good construction to ensure all the elements fit together properly. We were responsible for site supervision as well, while a lot of the design was done back at the office.”
Coordination was critical as a lot of the bridge structures were being built simultaneously. “It was a very tight programme that required us to be at many places at the same time,” says Al Muti.
Interestingly, the mega project has not been affected by the downturn in the construction industry, which also saw a marked slowdown in ongoing projects and new contract awards in the capital. “Luckily it was not affected at all.
We thought it might be affected. They had the budget allocated. We were reading about the situation and saw so many projects stopped, but this one started at the peak and continued all the way through. We were did not have any gaps; payments were done on time to us and to the contractor.”
Al Muti says “this has been one of our largest projects here in the UAE, and one of the most complex.” The mega project has also been interesting in showcasing the infrastructure capabilities of Atkins, which is normally associated with iconic buildings such as the Rocce Forte Hotel in Abu Dhabi.
At present, the Atkins team is busy scaling back. “We have a small team remaining on-site, as we only have a few small junctions left to do. All the major work has been completed, all the drawings finalised and manuals finished,” he concludes.
Al Maryah Island
Al Maryah Island, formerly known as Sowwah Island, is set to be a dynamic mixed-use central business district, as designated by the Abu Dhabi Urban Planning Council in the Capital 2030 Framework Plan, formerly the Plan Abu Dhabi 2030.
Al Maryah Island is a 114ha mixed-use development that will be a vibrant, 24-hour commercial, leisure and entertainment hub, with premium office accommodation, comprehensive transport infrastructure and connectivity, a pedestrian-friendly public realm, luxury business hotels, residential neighbourhoods and a variety of retail options, together with community facilities, public amenities, parks and open spaces.
The island occupies a unique location at a midpoint between Abu Dhabi’s existing downtown district, the upcoming developments at Reem Island next door and Mina Zayed, as well as the new cultural district on Saadiyat Island.
In this strategic position it thus creates a natural hub for Abu Dhabi. It is also classified as an investment zone where UAE and GCC nationals can acquire freehold land.
Other international investors will be able to obtain long-term musataha (right to build) or usufruct (right to use and exploit) land rights on the island.
- 180,000m2 Premium commercial space at Sowwah Square
- 1,048,470m2 Land area of Al Maryah Island
- 569,756m2 Total plot area
- 4.5km Length of podium-level bridges, elevated structures and ramps in Phase 1
- 7km Total length of service roads in Phase 1
- $51.3m Value of four bridges in Phase 2 package