Site visit: MEP at World Trade Centre, Abu Dhabi

MEP Middle East went along to have a look

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The residential (left) and office (right) towers protruding from Abu Dhabi's World Trade Center site
The residential (left) and office (right) towers protruding from Abu Dhabi's World Trade Center site

As work on Towers 2 and 3 of the World Trade Centre project in Abu Dhabi rapidly approaches completion, MEP Middle East went along to have a look before business is all wrapped up

Boasting the tallest building in Abu Dhabi, the World Trade Center project is not hard to find. Located just off the UAE capital’s corniche on the site of the old Central Market, the $1.6bn (AED 6bn) Aldar Properties development is a five-building cluster connected by a common basement and under-construction mall.

The project’s centrepieces are towers 2 and 3 – the first a 96-floor residential supertall at 382 metres in height, and the second a 61-floor office block reaching 277 metres, both of which stand on five basement levels.

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The MEP project on both towers is being led by Voltas’ A R Suresh Kumar, project director, with an extensive contracting crew in support which includes Waqar Nazir, senior planning manager, and Hitesh Bhatia, senior project manager.

Voltas was awarded a $190.6m (AED 642m) contract for MEP works on the two towers by main contractor Arabian Construction Company (ACC) in February 2010. Mobilising on site a few weeks later in March of that year, the MEP contractor was presented with a project that was at a surprisingly progressed stage of completion.

Civil work on the project had commenced in August 2007 and on Voltas’ arrival slab work on the 80th floor of the 135,000m² (built-up area) Tower 2 was being cast, while the civil works on Tower 3 were already complete with façade work ongoing.

Nazir, who has been on the project from the outset, explains why the contract award came at such a late stage: “The MEP design was not yet complete, even when we received the award,” he says.

“Prior to that, the main contractor, the client and consultant were jointly trying to address all the problems they had with the design. The MEP consultant, being new to the region, had to seek assistance from the main contractor to comply with the initial local authority requirement and that delayed the MEP award even further.”

When the award was finally made and Voltas arrived onsite, it was instructed to prioritise work on the Tower 3 office block as its MEP design was “fairly complete”, according to Nazir. MEP work on the almost 135,000m² Tower 2, which was still very much in the design stage, did not commence until three months after Voltas began work on Tower 3.

Faced with two distinctly different tower buildings to complete, Voltas’ approach to tackling the project has seen a separate team assigned to each.

Both teams have encountered the rare experience of having no civil team to work around or wait upon as the towers’ structures were almost entirely complete. While this provided a degree of freedom to attack the installation project head-on, Voltas having the place to itself brought its own challenges.

“When a building is already constructed and given to you, the MEP project requires parallel working because so many floors are available at once,” says Kumar. “Normally, in other tower projects, you get roughly four to five floors on which to start. Here we got dozens of floors to work on simultaneously.”

Nevertheless, setbacks to the project’s completion would come with a sizable change to Tower 2’s MEP design quite some time after Voltas had already commenced the installation.

“The MEP project would have been quite smooth if it was not for some changes which took place, particularly in Tower 2, where the apartment mix was changed,” says Nazir.

“Initially it was mostly one and two-bedroom apartments throughout the building, but post award the client advised to alter the mix of apartment types for the upper half of the tower. This redesign, along with the addition of another consultancy team, delayed the project by about a year.”

Further design changes to plant rooms to meet with ADDC’s (Abu Dhabi Distribution Company) requirements has seen the completion date for Tower 2 pushed back from its original target of June 2012 to August 2013.

While the delay caused by design changes was largely suffered by Tower 2, work on both buildings has had to circumvent the obstacles involved in operating amid a built-up residential area in a bustling area of the city.

Beyond considerations concerning noise levels and their affect on those living in the project’s vicinity, the logistics of getting manpower and material to site on time every day posed a significant problem. Voltas was required to employ a large team devoted to planning and executing a tight schedule that would ensure a minimum of delays.

“We have around 130 to 140 workers with 3 or 4 senior staff working on the logistics in this project,” says Kumar.

“The project is not a horizontal one where you can reach your workers at any time. In terms of waiting time and putting the workers, tools and material in place, it’s been difficult. If you miss a small item, that can possibly hold back the work for the next two hours. The logistical challenge is exacerbated by having no site storage.”

Bhatia adds: “We are storing materials in Meena [10km from the site] so a lot of thinking and planning has had to go into this project. We are also working with a lot of high-quality materials sourced from Europe which means factoring in lead and approval times.”

Nevertheless, work on Tower 3 has been largely straightforward, give or take some minor complications. The building, with a built-up area of almost 113,000m², is currently in the handing over stage and stands at 99.85% completion.

Modelled on modern European and US tower projects, it is an impressively high-spec building with some interesting aspects to its MEP design. Beyond its power management system (see “Tower Power” segment), the MEP focus of the tower is on its protecting the building’s occupants.

“The main stress is on the life safety aspect of the project in Tower 3, which is well taken care of,” says Bhatia. “A building of this nature will have about 50 floors with around 400 people working on each,” Kumar adds.

“The number of people occupying this building is around the size of a small town in Europe, so safety is paramount. A lot of care has been taken by the consultants in the MEP design to ensure this.”

This consideration means the access control system, normally employed for building security, can be instantly adjusted to hasten the escape of evacuees. Barriers and doors are designed to immediately switch to “open”, while the revolving doors in the tower’s triple-height entrance foyer suddenly fold to what Kumar calls a “book-open” position, maximising the space through which fleeing occupants can pass.

Up in Tower 3’s office floors, a particularly unusual feature of the MEP design can be seen in the ceiling installation which utilises a racetrack design (running along the curve of the building’s core) and technical channel (services trough) layout to deliver the MEP services to the eventual occupants.

According to Nazir, the installation of this speciality design required a staggering number of separate fixes and demanded all the skill and patience the Voltas team could muster.

“As an MEP contractor it was a big challenge because we had to limit all our MEP requirements within the space of the technical channel,” he says.

“We had to incorporate the grills, diffusers, lighting, smoke detectors, everything into this channel. The metal interlock ceiling system design complicated the installation process and required seven fixes compared to the traditional two or three fixes.

We would install something and then the ceiling contractor would do the next stage of their work – a process repeated seven times. It was a large drain on man hours.”

“The alignment of each technical channel had to be perfect because if you touched something on the ceiling during installation, a whole section went out of line,” adds Kumar. “Each section of the technical channel came with a unique diagonal that could not be interchanged with other sections because the building is oval with a wavy-shaped façade, and so each section was unique.”

A further challenge was faced in the design and installation of Tower 3’s mechanical floors which can be found on B1, B2, 19, 20, 51, 52 and level 60. “This is a building with a core and a glass façade on the side, which posed a problem when installing all the required equipments,” says Kumar.

“It was like trying to put a square peg in a round hole: all MEP plant equipment traditionally require a cuboidal shape for ease of installation and efficiency. We are trying to fit them into a circular space. Space management was therefore one of the biggest challenges.

“Normally in a glass building, the plant room will also have a glass façade, but here the client has taken a decision to prevent the sound from passing into adjacent areas, so they are protected by a ring wall. This has also reduced the space available to us when installing the plant equipment.”

However, the struggle to fit-out Tower 3’s plant rooms did eventually yield some benefits. Having started work on the tower’s mechanical floors well before those of Tower 2, Bhatia says a lot of the difficulties encountered in Tower 2 could be resolved quicker given the experience gained on Tower 3. “A lot of learning from this tower has been used in Tower 2,” he says. “We had fewer problems with the plant rooms there as a result and we were able to do them in one schedule.”

This applied learning has seen Voltas construct the plant rooms in Tower 2 in a truly impressive time.

After waiting for the design to be finalised due to changes in compliance with ADDC regulations, which added a further delay to the schedule, the contractor starting putting together Tower 2’s plant rooms in October 2012. Just seven months later, the plant rooms are in the process of commissioning.

“A plant room of this nature normally takes about nine to twelve months,” says Kumar. “When we told the consultant that we were ready to take the challenge of completing the plant rooms by the end of May, everybody was laughing at us. They thought it would never happen and said we were overstating and overcommitting.”

This time gain meant that Tower 2 stood at around 87.4% completion as of early May, with most of the services throughout the building fairly complete and wild air up and running.

The remaining months till August will see the contractor winding down operations on a project that has seen it deploy around 2,400 workers and 150 engineers and supervisors at its peak, and adding the finishing touches to what is already one of Abu Dhabi’s most spectacular projects.

Tower Power
With Tower 3 set to provide workspace to around 20,000 people, a major consideration when designing the building was minimising the energy consumption of such a vast number of occupants.

Central to achieving this is a lighting management system which utilises natural light as much as possible in order to save energy. Tower 3 has photo sensors available on each floor so that the luminescence of the building’s lights is adjusted depending on the brightness of the natural light outside.

These are augmented by sun-tracking sensors on the top of the building which automatically change the angle of the blinds in each office floor to maximise both light-saving and occupant comfort.

The lighting management system also employs occupancy sensors 24 hours a day throughout the building which allows interior lighting to switch off automatically when an area of the building is not in use.

Together these create a system that limits the strain on the Tower 3’s lighting, a lot of which are energy efficient and low-maintenance LED fittings. In addition to this, the return air at each floor passes through the building façade to reduce the level of heat gain through the building façade, this helps in reduction of energy consumption for cooling systems.

Kumar says the building’s power management system also provides the structure’s consumption with a great deal of flexibility. “The building’s power management system allows it to load shed and control all the power issues within the building such as switching on the generators when requireed and changing the feeders.”

In numbers:
- 300,000 Number of light fittings in towers
- 8,500 Kilometres of cables in towers
- 60,000 Chilled water valves in towers
- 40,000 Sprinklers in towers

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