Gulf Construction Online

Dubai Investments Building

the building ready for occupation.

Two-in-one

A commercial and residential building for Dubai Investments at Al Qusais in Dubai has been completed. A look at the techniques used in its construction.

01 December 2001

Work on Dubai Investments' high-quality commercial and residential building at Al Qusais in Dubai, UAE, has been completed and the property is currently being leased out, according to the project manager Union Properties.

The elegantly-designed building occupies a prominent 42,400 sq ft site on Al Qusais Road next to Al Bustan Centre. It is also in close proximity to the Dubai International Airport.

Construction work started in August 1999 and the project was handed over to the client at the end of October this year. One of the tenants - the Commercial Bank of Dubai has already moved in.

The external appearance of the project actually belies its true nature. Although it appears to be one building on the exterior, it comprises two buildings - one commercial and one residential.

"The project started off as a commercial complex and during the construction stage, the client acquired an adjoining plot to construct a residential building,'' says Ma'en Salameh Saleem Al-Zawaideh, project manager with Union Properties.

The buildings comprise of a basement, ground plus four floors.

The office building, which has a central full-height atrium, has showrooms on the ground floor and a car-park in the basement. The block has three entrances, the main one in front of the building and two side entrances. Four lifts service it.

The office block offers commercial space on open-plan floors, which can be customised to suit any potential requirements. It has a total built-up area of 152,985 sq ft with the basement covering 31,200 sq ft, ground floor - 22,055 sq ft, typical four floors being 24,635 sq ft each and the roof, 1,190 sq ft. Each floor has two common areas for men and two for women. There are two pantries furnished with sinks and cupboards.

The residential building, which has car-parks in the basement and on the ground floor, opens on to a central open-to-sky courtyard. It has two entrances, including one from the basement.

The block has 34 high-quality apartments spread over four levels. Each apartment is a luxurious one-bedroom flat with the kitchen opening into the living and dining room. The bedroom, which has an attached study room, has built-in cupboards. The kitchen is fully fitted with appliances.

The residential building has a total built-up area of 65,944 sq ft with the basement covering 11,200 sq ft, ground floor - 10,801 sq ft, the four typical floors 10,798 sq ft each and the roof 751 sq ft. Its car-parks can accommodate 165 vehicles. It is served by two lifts.

A fully-equipped health club and sauna are located on the roof.

"The external facade is covered with double glazing glass, which provides protection against humidity and high summer temperatures. Granite cladding is used for the ground floor," says Al-Zawaideh.

"Internal walls of the ground floor of the office block and all the floors of the residential block were constructed of blockwork with the upper floors of the office areas having a lightweight partition system," he says.

He continues: "Finishes to the main areas are in marble. The walls and floors of the bathrooms comprise ceramic tiles. Corian solid surfacing was used for the vanity tops in the residential block while granite was the material chosen for the commercial block. There are gypsum board decorations in the common areas, with 60 by 60 cm false ceiling tiles installed in bathrooms and kitchens."

"The complex is centrally air-conditioned," says Sridhar Thirumalai, a civil engineer with Union Properties. "There is round-the-clock security with CCTV and audio/visual intercom. The building is also provided with a dish antenna and free-to-air channels."

"The complex has been built to very high standards similar to the buildings located on Sheikh Zayed Road," says Al-Zawaideh. "It is equipped with an access cradle to facilitate cleaning of the glass-clad facade. It also has a garbage disposal system with a compactor.''

There are also plans to landscape the front of the building.

Construction

The foundation of the building comprises piles and pile caps. The superstructure has a composite construction using steel and concrete combined to produce a cost-effective structural system.

"Both steel and concrete have their own advantages and disadvantages as structural materials," says a spokesman for Emirates Building System, which supplied and erected steel for the project. "It is therefore beneficial to introduce a structural system that exploits the advantages of both materials in a unified structural system.''

The spokesman continues: "Structural steel offers high-strength properties which make it cost-effective. Steel is well suited for providing column-free lease space required in contemporary multi-storey buildings. The pre-engineered system helps increase the speed of construction and improve flexibility in interior space planning.

''Reinforced concrete is used for its stiffness. The inherent stiffness of concrete is used to advantage to control building sway under lateral loads.

"The optimum combination for multi-storey buildings is a composite system with a steel frame stabilised by reinforced concrete.

"The basement has a perimeter wall constructed of reinforced concrete, which retains soil and surcharge loads. The perimeter steel columns are supported on top of the RC retaining wall.

''The interior steel columns were founded at basement level on individual RC pads.

''The steel concrete mix helps minimise the building weight and is worth considering in order to reduce costly foundation systems.

"One of the advantages of the steel construction is the use of decking for floor construction, offering a more flexible system to allow easy service installation and facilitate future changes in layout. A steel frame is simpler to modify to meet the changing needs of the tenants and architects over the life of the building.

"With steel framing, it is less expensive to increase the load capacity of the floor framing system or cut holes in the floor to install stairways, atriums etc.''

For the building, the floors were typically constructed with a 75-mm trapezoidal deck and topped with 55 mm of lightly reinforced concrete. The overall depth of the floor was 130 mm.

"The commercial block used decking with composite action spanning 3.6 m. The selection of this decking allowed an unpropped construction, minimising erection costs. The use of high-strength light gauge metal decks with embossments in their ribs helped achieve composite action with the concrete. This has become one of the standard methods of slab construction for multi-storey buildings.

"The decking in the residential block was not composite. The construction programme was very tight which created problems in the delivery of this decking. A similar decking profile was used without the embossments, thus making it a decking used only as formwork to allow the wet concrete to cure. As compensation, the concrete was designed to sustain the serviceability loads as a ribbed slab.

"The building employed composite beams with the use of welded shear connectors. The stiffness of composite beams in typical steel buildings is at least 40 per cent more than a normal steel beam within the positive moment region - thus allowing a reduction in beam size and improving the cost-effectiveness of the floor system.

"The main support columns in the building were various sizes of rectangular hollow sections filled with concrete. Steel structural hollow sections are most efficient in resisting compression loads and are designed to carry the dead load and construction load of a limited number of storeys during construction. With the addition of the concrete infill, there is a dramatic increase in the combined section axial capacity, thus allowing smaller section sizes. This type of column helped to reduce the physical column size in the basement and allowed a greater number of car spaces.

"Structural stability was achieved with the interaction of the two reinforced concrete cores. Thus, the lateral loads from wind acting on the face of the building are then distributed to various floors which, through diaphragm action, transfer these loads to the horizontal shear-resisting elements such as vertical RC shear walls. Shear walls are traditionally adopted around the cores, which enclose the stairs, lift and services shafts. The walls are usually C or I shaped and interconnected with bridging beams to create an integrated laterally stable structure.''