As its pace of development heats up, mega-projects are becoming the norm in Abu Dhabi.
Construction projects in Abu Dhabi are setting new standards in scope and innovation. Construction Week visited the Capital Plaza Development to learn about the ground-breaking techniques needed to build one of the city's first mega-projects.
As its pace of development heats up, mega-projects are becoming the norm in Abu Dhabi. Recently enormous schemes have begun to transform the islands surrounding the capital into vast developments.
But there are also a number of ongoing schemes in the city centre itself. One of the first to be launched was the Capital Plaza Development in The Corniche area of the city.
The building is being constructed by Arabian Construction Company (ACC) for its client Real Estate Investment and Services (Reisco). When finished it will consist of five towers, reaching up to 45 storeys.
Construction Week visited the site and met with Ashraf Bazzouni, senior projects manager, ACC.
He says there had been a number of challenges in constructing the building, especially as it was leading the way in the city's building boom.
Perhaps the most taxing of these had been the size and location of the site.
The plot is 13,000m², with the buildings taking up 9,300m² of this.
This is particularly small, with an average- sized plot being about 15,000m².
Work is made even trickier by the proximity of the surrounding buildings - the nearest one is only 7m from the site.
Bazzouni says because of this, a high level of coordination was needed to make sure the project runs smoothly.
He says: "At the moment there are 1,400 workers but at its peak it will be 3,000.
"At the moment it is like having a big-size family sharing a studio apartment.
"But it is going to get even more crowded when the civil work is finished and the sub-contractors move in.
"We are having to coordinate things very, very carefully to make sure everything can work well and safely.
Because of the site's short distances from roads and pavements, safety has been the number one priority for the construction team. Bazzouni says: "Prior to construction we do a risk assessment on safety for all the activities to check what the safety hazards are.
Formwork and concrete pouring is one of the most critical activities at height, especially in a congested area like this.
"The probability of having an accident is high so we are very stringent in applying safety on the site.
"Thank God, so far we have been mainly accident free although there have been some small incidents which we are dealing with on a one-to-one basis.
"We have to pursue all the precautions we can to make sure people inside and outside the site are not injured.
Because of the small size of the site and its relatively lofty heights, extra deep foundations work was needed.
However, during the excavation work engineers found that the soil conditions were not good enough to meet the strength required to support the building.
A third party engineer confirmed this fear and the project was suspended for seven months. During this time, the construction team went back to the drawing board and came up with new plans.
It was decided the only way to support the weight was to build an extra-thick diaphragm wall to reduce the amount of piling.
The diaphragm wall, when built, was 2.1m thick, which Bazzouni claimed was the thickest ever made in the world.
He says: "This is unique for this project and I don't think it has happened anywhere else in the world. It had to be so thick because of the shape of development and the proximity of the buildings.
"The plot shape caused huge forces as well as the depth of the excavation, which was 20m deep. Usually you will go to about 13m for three basements; here we are going five basements deep." To support the wall during construction, huge struts were needed.
These were 2m across, 3m wide and up to 60m in length.
Bazzouni says: "This is the first time they were ever constructed in concrete because the stresses were so huge that steel would not have taken it.
The challenge for the contractors was to support the struts on a temporary basis without affecting the permanent structure and then removing it from the site.
Each strut was supported down to the raft and then, when the walls had been finished the beams were cut into pieces with saws and removed by crane.
The operation took three months to complete, but again was completed effectively.
Bazzouni says: "Each piece weighed 60 tonnes.
"We cut it like a piece of cake, but a really heavy piece of cake.
"It was one of the most difficult jobs we have ever done because it was unique; it was the first time it has been done, to my knowledge, in the world.
"We removed them without accident and received congratulations of the client. It was one of the turning points of the project.
The success of the foundation work has also given the client scope to possibly increase the size of the project.
Bazzouni says: "The structural designer is studying what is the maximum number of floors we can actually go for.
"The foundations are there and we can do nothing to change them, but we are talking somewhere between an extra two and six floors. They want to increase the floors as much as they can.
"As an investor based on the current real estate market whatever you build will have a good return.
Since the diaphragm wall struts were removed last year, work has begun on the above ground levels.
Now the project is about 16% complete. The basement area is complete and the podium level is finished to the second floor.
They have also started MEP installations in the lower levels.
The project is due for completion in September 2009, and Bazzouni was hopeful it would meet this deadline.
He says: "Every job is challenging, even the small ones, but this job has been particularly so.
"There is a lot of hard work left to do and new challenges will arise, but we have overcome some major ones and it is going quite smoothly.
"Of course we are proud to be working on the first mega-project in Abu Dhabi, but we will be even more proud when we are finished.
So although Dubai may have a much more vast scope of construction projects, Abu Dhabi is using innovative hi-tech techniques which arguably surpass its neighbour.
And Bazzouni predicted that the capital would one day match Dubai in the amount of construction work.
He says: "I don't see any difference. Abu Dhabi will one day be bigger than Dubai. The plans are more ambitious.
"It is the capital of the country and the future is very promising here. By expanding around the surrounding islands, the sky is the limit.