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Sun 4 Nov 2007 04:00 AM

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Island life

How do you design and build an entire city on an island within less than ten years? Alison Luke finds out at Shams Abu Dhabi.

Fresh on the design map only a few years ago, the concept of offshore developments has quickly grown in popularity. Islands of ever more elaborate designs are being created around the Middle East's coastline, but some developments currently underway in Abu Dhabi are being approached differently.

Rather than create a new land mass for its latest landmark venture, Sorouh Real Estate has opted to develop a city on an existing island. The firm's Shams Abu Dhabi project will be built on Reem Island, which is located a few hundred metres north-east of the capital city. Separated from the mainland by an area of natural mangrove, the development is being designed with respect for the natural environment. "We are taking extra measures to maintain and safeguard the mangroves, which need a lot of maintenance because the area was deserted for a lot of years," explains Mohammad Meerza, MEP manager, Sorouh. In addition, energy efficiency and sustainability are high on the agenda for the MEP services. One of the biggest challenges facing the project team involved is that of co-ordination.

Canal co-ordination

Shams Abu Dhabi stretches across a 1.74 million m2 area of the island and is entered via the landmark Gate District. With a site footprint that is shaped like a fish, the mixed-use development will comprise several hundred buildings including commercial, retail and residential properties. These will be built and operated by several different firms to an overall masterplan. A network of canals and waterways is intended to help maintain the water flow into the mangroves as well as provide a transport network and signature feature of the project. These canals have also provided one of the biggest challenges for the distribution of MEP services.

"Getting the utilities to cross the canals was one of the major achievements," stresses Meerza. "It was quite an engineering feat because you have to go below the canal level." Depending on the services involved, distribution in these areas will be either through a duct bank or culverts. This work will be completed then the canal and bridges constructed on top.

The utilities infrastructure was by necessity one of the first jobs to begin on site, starting in early 2006, and is now well underway. Part of bridge contractor Nurol's contract is to install the facilities for the canal crossing points on the distribution network. The earthworks plus deep and shallow sewer networks are complete and installation of the other utilities is beginning.

Before this work could begin, a major challenge for the utilities distribution network was to ensure that each service can be accessed at every point where it is needed and no clashes arise during the construction period. A difficult task on any project, this has been increased significantly due to the sheer scale of the area to be covered and the number of individual projects being constructed within Shams. Overcoming this challenge has involved the use of three-dimensional computer modelling and considerable time in the design stage to ensure minimal problems will occur on site.

"Because every service is underground you have to locate a particular design depth for them and all these depths have to be maintained at this particular level at every point of this development," stresses Meerza, "If during design you miss something, once on site it is going to be very difficult to resolve this.

"Making sure that everything is in the assigned design area is one of the most challenging things. In some projects people have installed underground services and have had to go back and redo it. This is a time cost, financial cost and [the final system] doesn't look good."

Keeping cool in central park

One of the main public areas within the Shams development will be the Central Park. A landscaped space of 84,600m2, a mix of architectural, landscaping and mechanical services will combine to maximise the comfort of park users.

The park is set to include various buildings such as an amphitheatre, galleries and retail outlets as well as a network of water features. To increase its usability in the local climate a number of measures have been taken to reduce the relative temperature in the park; these include passive cooling, water misting and the careful orientation of structures and canopies.

"We are not trying to air condition an outside space, we are trying to modify the climate to maximise its use," stresses Raymond Crane, director, Arup. "For example, to reduce the radiant temperature in seated areas we have introduced as much shade as possible."

The orientation of various structures within the park has been planned to funnel the onshore and offshore breezes around the areas where people may be walking, again to provide a relative difference in temperature. "Evaporative cooling will be used fairly discreetly," adds Crane, "There will be a lot of water flowing through the park and the evaporation of this is one way of cooling the surrounding air temperature," he explains.

A more mechanical means of evaporative cooling will be provided by means of misting sprays. The spray nozzles will be hidden within architectural features and can produce a significant temperature difference. "We ran a model and it showed that this could produce 6-7°C difference [in air temperature]," explains Meerza.

"Some people may believe that it is too humid in the region for this type of system, but the psychometric charts for Abu Dhabi show that you can effectively use misting and evaporative cooling for around 90% of the year," assures Crane.

Further cooling will be provided by diverting the chilled discharge air from the air conditioned spaces such as the retail stalls into the outdoor seating areas. "The [air conditioning systems] will be run with 20-30% make-up air, so any discharge air will be ducted to create chilled areas [elsewhere in the park]," explains Crane. "We have designed the plenums for the air conditioning so that ductwork can be connected underground to divert the airflow to the seating areas," he adds.

One of the more unusual systems being planned for Central Park is the use of seawater to cool the park benches. Currently at concept design stage, this would involve diverting some of the seawater that has been pumped from depth to serve the parks water features into a closed-loop system that would run through the bench seats.

"[The benches] will be chilled by seawater running through cavities and cool the users," explains Meerza. "The seawater is relatively cool at around 28-32°C, whereas the air temperature is plus 40°C a lot of the time, so we're trying to use this difference in temperature to temper the environment," adds Crane.

The climate control solutions for Central park are being designed by Arup's Boston office.

The assignment of specific depths for each service will enable the vast amount of services to fit into the limited available space, plus it will ease the connection to buildings once they are complete. After the deep and shallow sewers the district cooling network will be installed, with the remainder of the services such as electrical power and telecommunications cabling positioned at a higher level.

Logistical developments

It is not only the MEP utilities that have required such close co-ordination, logistics is a major challenge for the overall development. The entire project is scheduled for completion in 2011, making it a fast-track development. With multiple large-scale projects to construct and a relatively small access point to the mainland, decisions had to be taken early to ensure that the masterplan could be created both in time and to the standards planned.

"This is a single-phase development," explains Meerza, "we have done a logistics plan and are building in different areas depending on our particular requirement for that area." Individual developers are being allocated access for construction on plots strictly according to the overall logistics plan, with 29 sub-developers already on site.

"One of the most important things for us was the pre-planning - not only of the services but also the logistics," stresses Meerza, "We are not only building the infrastructure, we are also doing the buildings and this is a big logistics exercise." To ensure the construction programme is maintained, a system has been developed to determine the status of every plot on the development at all times. "We have allocated numbers from zero up to five so that we can monitor every plot here to see exactly which stage of development it is at and that also determines our logistics," Meerza adds.

The information will be compiled using an electronics package and displayed on a ftp site that can be accessed by the main contractors, consultants and overall project manager. This will also act as a record management system for correspondence and the meetings reports. In addition, weekly programme meetings will be held throughout the project's development.

To minimise co-ordination issues on site, the main contractor package tendered includes subsections for each other service involved in their works, such as electricity and water. "The idea was to not get involved in the co-ordination between the different services and let the main contractor employ their own resources to do this," explains Meerza. Packaging the work in this way will also aid the speed of construction, as all subcontractors will be approved as part of the initial main contract tender stage. Once a main contractor is appointed the entire team involved will be able to mobilise to site immediately.

Servicing Shams

In general, the mains MEP services will follow the same basic route. A main loop runs around the outer edge of the development, with a grid network stretching from this into the centre of the project to serve each of the buildings.

Project: Shams Abu Dhabi

Client:Sorouh Real Estate PJSC

Infrastructure design consultant:Hyder Consulting

Project managers:Hill-3D/I+PI

Main contractors:Earthworks, deep and shallow sewer - ADMAC

Marina and sea wall -Athena
Sky Tower (Tower 1) and Sun Tower (Tower 2) -ACC
Bridges -Nurol
Roads and utilities -Al Geemi & Partners
Architects:
Arquitectonica, RW Armstrong for Sky (T1) and Sun (T2) Towers
M&E Consulting Engineer:Ian Banham and Associates for Sky (T1) and Sun (T2) Towers

MEP Contractor:Thermo

Contract details for earthworks, deep and shallow sewer

Contract award date:31 July 2006
Construction start date:31 July 2006
Completion date:Dec 2007

Contract details for marina and sea wall

Contract award date:26 November 2006
Construction start date:23 January 2007
Contract period:10 months
Completion date:November 2007

Contract details for Towers 1 & 2

Contract award date:14 January 2007
Construction start date:14 February 2007
Contract period:38 Months
Completion date:September 2009 (Phase 1)

Contract details for bridges

Contract award date: 10 April 2007
Construction start date: 16 May 2007
Contract period: 21 Months
Completion date: February 2009

Contract details for roads and utilities

Contract award date:19 September 2007
Contract period:21 months
Completion date:July 2009

Guidelines determine how the buildings must be serviced to ensure that Sorouh's goal of a sustainable development can be met. "Generally the building guidelines are clear on what [developers] have to achieve, for example they have to use district cooling and will be supplied by a 22kV electricity network developed according to ADWEA/ADDC standards and specifications. Potable water will be supplied by ADDC and Abu Dhabi Rules and Regulations must be met," explains Meerza.

In addition, several design aspects and technologies have been considered according to their suitability for the individual buildings. "We've been discussing using solar energy as much as possible or using glass facades with a very low co-efficient of performance so that you get light, but you don't lose the cold air...we are trying to design the buildings in such a way that they are energy efficient," confirms Meerza.

Water services

The insistence on district cooling rather than individual chiller systems was made in an effort to reduce both electricity and water consumption on the development. "It is mandatory to use district cooling; with this you can reduce the power usage by up to 30%, therefore the design of the electrical network is based on a district cooling system and not conventional packaged air conditioning," explains Meerza.

Four district cooling plants will be constructed for the project, with a total capacity of 200,000TR. The southern end of the development will be fed from one 80,000TR plant; the northern area will be served by three plants of 40,000TR through a linked network. The distribution network ensures that a connection is available at every plot.

The division of the district cooling provision was made for operational reasons: "We didn't want to have such a huge area interconnected - after looking at the hydraulic calculations and the hydraulic model it was decided that we'd have this southern sector fed from one plant and the northern sector fed from three plants of 40,000TR," explains Meerza. A further reason for dividing the total capacity is the size of the pipes that would be needed to distribute the chilled water from one plant. "If it becomes too big, then your outgoing pipes become huge," states Meerza, "for example, the 80,000TR plant will have pipes of approximately 1200mm diameter, which means two outgoing and two incoming pipes of this size."

To further increase the sustainability of the district cooling system the amount of potable water used will be minimised, instead treated sewage effluent (TSE) will be used as make-up water. A sewage treatment plant (STP) will be built on the island and the TSE from this used in the district cooling system and for irrigation.
Two further methods of reducing the consumption of potable water have been proposed. The first involves the collection of condensate water from the fan coil units (fcu) installed in buildings throughout the development. This system is proposed for all buildings where it will be economically viable, which Sorouh has calculated to be those requiring 800TR or more cooling. "People don't believe [that the use of fcu condenste is viable], but on a development like this I can have a four inch (101.6mm) pipe running full every day - that's a lot of water," he stresses.

The second option being considered is the use of a reverse osmosis (RO) plant to provide grade two water for the district cooling and irrigation networks. "We are doing a water balance and depending on the results of this we will [make a decision]," states Meerza. Potable mains water is being supplied via a 1200mm diameter pipe directly from the mains system in Abu Dhabi. The same pipeline will eventually feed the neighbouring Saadiyat Island also.

Getting electrical

A 22kV open loop electricity network will serve the Shams development based on Abu Dhabi standards. One 400/132/22kV grid station and four 132/22kV primary substations will be built on Reem Island, with two of these located on Shams property. This will also be one of the first developments in the region to include a fibre-to-home network. "The conventional connections used to be vertical fibre and horizontal copper, but we are taking the fibre to every apartment so [residents] can connect to the fastest available system," explains Meerza.

A further unusual aspect of the services being provided to homes in Shams is the network availability of natural gas for cooking. Again one of the first developments to do this, ADNOC-Distribution has committed in principle to providing natural gas for Reem Island.

"The reason for using natural gas is because we have high-rise buildings and lpg is complex in buildings of more than 20 stories," states Meerza. Most kitchens will be designed to offer the options of both electricity and gas. The gas pipeline is due to be complete by 2010, however as some of the residential properties are scheduled to be let to residents in 2009 a temporary solution has been created.

"A substitute natural gas (SNG) plant within Shams will be developed and tenants who are living there [before the gas pipeline is complete] will have this facility. When the mains natural gas supply line is connected it would then be simply a matter of removing our connection and putting it onto the mains supply and user won't have to do any adjustments to their cookers or appliances," explains Meerza.

Sorouh estimates that the planned design measures for the MEP systems will result in savings of 30%-35 electricity and up to 65-70% of potable water supplies.

Shams Abu Dhabi: the projects

There will be several large-scale projects constructed on Shams Abu Dhabi. The following is a selection of those already announced:

The Gate District -One of the most recognised of the Shams Abu Dhabi projects, this will include eight high-rise towers that provide the entrance to the development. The mixed-use project will include residential, retail and hotel accommodation.

The Sky Tower -
A 74-storey elliptical building that will include residential and commercial spaces assembled vertically around a central core. Designed as a green building, a range of technologies will be implemented to reduce the use of water and energy in the building. Separate lobbies will be provided for corporate and residential tenants to ensure security.

The Waterside Residences -A signature project for the development, this residential community will comprise low-level housing and be situated alongside natural and man-made canals.

Tameer Towers -Tameer's flagship project on Shams, this will include a 73-storey commercial tower that will have a 650ft-high prismatic atrium. The building straddles one of the development's canals and includes a private marina. The US $1.9 billion (AED7 billion) project will also include a seven-star hotel, serviced apartments and four residential towers.

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