Looking up in Downtown Dubai
Dubai Mixed-Use has forged ahead amid design changes
Slower construction activity in Dubai’s Downtown area in the last two years has left much of the space between Sheikh Zayed Road and the Burj Khalifa vacant and dusty for the trawl of tourists coming from the Metro. But one project and contractor has been forging ahead as if the market is still at its peak.
Arabian Construction Company (ACC)is the lead builder behind Dubai Mixed-Use, a project – as the name suggests – that encompasses residential apartments, office space and a hotel.
A five-floor podium was fully completed structurally a few months ago, on top of which stands one tower progressing at full pace, and a second tower frozen at level five.
Behind the podium lies a seven-storey car park, which will eventually fully link to the podium via two bridges at the fifth-floor level, and two tunnels.
The tower currently halted at five floors will eventually be a 31-floor hotel. This part of the project has been subject to a dramatic redesign from the private office of HH Sheikh Hamdan bin Mohammed Al Maktoum.
While ACC awaits the final design drawings, this structure remains quiet.
Project manager Mohamed Hamze explains that the redesign was due to an understandable adjustment to the changing market in Dubai since the launch of the project in 2008; in particular, that it will lose more than 20 floors in the new drawings.
ACC must now adjust to the new challenge.
“Before, the hotel had 56 floors, now it has 31, so now you want to save construction [materials] – for example, steel of 560t is now 350t. Maybe it is better when it comes to occupying the hotel to have it busy. A construction company will be affected – [but] since this is needed, you have to live with it.”
The tower next to it, by contrast, is racing into the sky thanks to an efficient team of workers and some key innovations. The structure will be 49 storeys, with office space up to the 17th floor and apartments above.
Hamze is adamant that a contractor must forge ahead on a project where possible. This means that, having completed the podium and car park, the company can hold off on constructing the bridges while the tower structure takes shape.
“The gap between the carpark and the width is about 20m and height about 3m. Instead of stopping work you will do some preparation work to see how you can proceed with the building without needing to finish the tunnel. It is important to keep construction moving.
The façade will provide perhaps the most distinctive element of the building, with multiple folded glass creating a dizzying ripple effect up and down the structure.
As with similar tower projects, including the company’s own work on the Almas Tower, the construction of the towers two reinforced concrete core walls are always a few floors in advance of the slabs.
“After the first phase of the podium is done, you start thinking,” he says. “The first priority is the core wall.”
The company is able to lay one slab every six days, on average. Hamze says the company was able to lay one slab every four days for the Almas Tower by splitting the slab into three sections, whereby a different task is carried out in each section and then the work is rotated.
On Dubai Mixed-Use, the slab is split into two parts: while one part works on the steel work, the other part works on the shuttering.
One bridge will be two floors in height, the other will be three floors, and will provide both access for people as well as the services.
It is a similar set-up for the tunnels to lead from the car park: they will eventually give access as well as a route for the project’s utilities.
“The main chiller room, the power, the LV rooms, the transformer are in the ground floor of the car park, along with the water tanks and the firefighting equipment,” explains Hamze. The project is special within ACC’s wide portfolio, as it was recognised by the company as one with the highest degree of safety standards for 2010.
Roseweath Rodrigues, HSE manager for the site, says the award is on the basis of an inspection by the group HSE manager to all the contractor’s sites, and assessing safety performance on the basis of standardised criteria.
“There were 22 requirements for all projects – and on that basis the group HSE manager gives the award,” he says on the way through the podium first level. “The key thing is to implement best practices.
Normally, health and safety is just a desk-top activity; here we make sure it is implemented. We have stretchers; one is here [on the ground floor], one in the hoist. We also have a male nurse here. We are trying to make safety as practicable as possible; we have 177 permits.”
In a space in front of the podium on the first floor, steel is being prepared to be lifted to the top floor of construction. Bassam Fawzi Ichtay, assistant construction manager, says there is likely to be some landscaping on the top of the podium, subject to the final design.
He looks up at the side of the podium and says the surface is being prepared for the stone cladding.
“Now we are starting the external preparation for the cladding first, fixing scaffolding for all the cleaning surfaces. The area at the ground floor also gives access for concrete mixers for the casting of concrete pumped up from the ground floor.”
This commodity is being provided by Unibeton Ready Mix, a firm that has supplied concrete to a number of ACC projects. Rodrigues adds that regular safety checks are carried out on the pipeline.
“We check the gauge, and check the thickness of the pipe at different points and when it needs to be replaced.”
At the top of the structure, after a swift rise up the hoist, one side of the slab is wet with the water used to cure the concrete. One side of the building faces – and is very close to – Sheikh Zayed Road, with the other side facing the Downtown area and the Burj Khalifa.
“The slab is split so that one half works on the steel work, and the other half works on the shutterwork,” says Ichtay. Floor 44 was due for completion the day after Construction Week visited the site. It took two hours for it to be cast, and was cast during the night.
“On level 42 we do the preparation of the steel.”
Peri’s automatic climbing system (ACS) has provided the structure on which to build the core wall, and is comprised of four platform levels linked by ladders.
The central core of the building is rectangular 38m long and 8m wide. Specifically, the self-climbing system can concrete to a height of 3.85m at once using the company’s Vario GT 24 girder wall formwork.
The system is independent of any crane. Once a section of the core wall is finished, the structure can essentially be unlocked and moved up to the next required level using hydraulics.
“The ACS system can be used for when the corewall is three or four floors above the slab; it depends,” says Amjad Khan, area sales manager at Peri. “It does not affect the ACS system – the only issue for the contractor is in getting between the slab and the ACS system.”
He adds that the company has been working with ACC from the start of the project’s conception, and that it provided the single-sided Peri Vario formwork for the retaining walls at the foundation stage.
“The basement is 6.5m high. If you are constructing the basement wall, you only have to fix it on one side, with the piling on the other side,” he explains.
“When you have done the shuttering and piling and build up, you have to build the wall. You have the piling on one side and the Vario on the other side.”
By mid-January, the contractor is optimistic that the structure of the residential-office tower will be completed as soon as it receives the designs for the hotel.
At the same time, construction manager Raed Khaled Khadijah says the company hopes to have lined up the tender for the interiors contract.
“We hope to finish the structure in the next one-and-a-half months,” says Khadijah. “We hope to have it finished so that we can have the manpower move onto the hotel.”
Client: Private office, HH Sheikh
Hamdan bin Mohammed
MEP work: MAPCO
Steel and fabrication: Cicon
Cement: Ready Mix Beton