Kuwait

Work under way at the project.

Work under way at the project.

Kuwait

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01 December 2007

Automatic climbing systems (ACS) of formwork – being used for the first time in Kuwait – is helping speed up construction of the Arraya Office Tower, which is set to be one of the tallest buildings on the rapidly-rising skyline of Kuwait City when it is completed in November next year.

The 240-m tower forms the second phase of the prestigious Arraya Centre, a unique, integrated real estate development located at the heart of the capital city’s evolving commercial Al Sharq area.
The Arraya Centre comprises four major components: the office tower, a shopping centre, a conventions centre with multipurpose halls and a multi-storey car-park. The office and administration building with 58 levels, is almost twice the height of the adjacent hotel building that was finished in 2003.
The office tower has three basement levels, a ground floor featuring a lobby and tenant space, two mezzanine levels containing commercial and office space, 53 office floors, two mechanical floors, two refuge floors, upper and lower roofs with facade cleaning equipment and elevator machinery, as well as a covered and surface car parking facilities.
Designed by a US firm and Pan Arab Consulting Engineers (Pace), the $50 million tower offers a total built-up area of 500,000 sq ft.
Externally, it comprises two parts: a square glass element that rises the full height of the building and a limestone-clad mass that is canted at an angle in plan and in relation to surrounding street grids. The limestone portion of the tower recalls the established vernacular of the existing multi-use Arraya complex, which includes the 32-storey, a 300-suite hotel, conference and banquet space, a parking garage and a three-level retail complex with over 10,000 sq m of shopping area. The iconic top of the tower, which is surmounted by a telecommunications mast, is sloped and angled to create a unique and memorable image for the entire complex.
The development, which was envisaged in March 2005, had its foundation stone laid in September of that year. Among the first challenges faced by the project was the construction of a piled raft foundation system to a 3 m depth with an excavated level of -18.00 m below ground level.
The excavation and piling works were completed in November 2005, and the raft foundation by March last year, which enabled work to commence on the superstructure.
The superstructure comprises a shear wall skeleton structure, formed using the ACS for the walls and Skydeck for slabs. Casting equipment has included a climbing placing boom that is connected to a stationary pump, and luffing cranes. A self-climbing luffing jib tower crane will be used to assist in the installation of the architectural mast of the tower that is approximately 55 m high above the last concrete. Grade K600 and K450 concrete is being used for the construction of vertical elements and horizontal elements, respectively.
In order to be able to complete the planned construction as efficiently and safely as possible, the contractors decided in favour of a rational combined use of ACS self-climbing formwork, RCS climbing protection panel as well as the Skydeck panel slab formwork, supplied by Peri of Germany. The 4 m standard floor heights featured slab thicknesses between 17 cm and 28 cm.
“The Peri systems we used contributed significantly to the fact that the concreting steps could not only be constructed quickly at great heights but also extremely safely,” says Attia Yousef, project manager. “The use of an automatic climbing system for the first time in Kuwait, enabled rapid construction of core walls to up to four floors ahead of the slabs at an average cycle rate of six to seven days per floor; while the use of Skydeck aluminium panel formwork system enabled rapid construction of slabs. In order to match the rapid cycle time of the ACS system, Skydeck has been adapted in this project.”
Elaborating on how the formwork was used on the project, a spokesman for Peri says: “Construction of the two separate reinforced concrete cores took place in advance with ACS self-climbing technology and Vario GT 24 girder wall formwork in regular weekly cycles, which meant shuttering, striking and climbing could be carried out without the use of a crane and in all climatic conditions. For optimal working procedures, two versions of the modular ACS system operated next to each other. The placing boom was also lifted with the ACS from section to section.
“The RCS climbing protection panel completely enclosed the slab edges of the trailing floors. Protected against strong winds, construction site personnel could work safely and productively in the top three storeys even at great heights. Mobile self-climbing devices from the RCS modular system ensured crane-independent climbing with reduced and therefore cost-effective on-site material requirements.
“In order to be able to maintain the planned weekly cycle, also when constructing the slab floors, the 850 sq m area on each storey was formed using the Skydeck system. The lightweight aluminium elements allowed simple, non-tiring and fast assembly, and with the drophead, early striking could take place. This meant that the main beams and panels were free to be used for the next cycle.”
The bid packs of the project are currently in various stages of completion. While the building works (Bid Pack 2) is due for completion next June, the external envelope will be up by August and the interior architectural as well as external works will to be finished in October next year.
The building also incorporates advanced data and networking systems with a single point of connectivity for telecommunications, television and data networks. All services have been integrated into a unified IT backbone. Arraya was one of the first in the Gulf to implement this system  with the various components for the hotel, offices, and shopping centre integrated as one system.
The external façade of the building will feature stone cladding up to 17 m high and a curtain-wall plus aluminium cladding above this height. The public areas will have marble stone cladding wall finishes. Other finishes include gypsum board for ceilings.
Some of the mechanical and electrical works of this project includes:  
• HVAC: water-cooled centrifugal chillers with a total capacity of 1,700 tons of refrigeration, along with VFD-driven pump sets and VAV air handling units (AHUs) controlled by a state-of-the-art building automation systems are used to serve the comfort air-conditioning requirements. Electric heaters are proposed to serve preferal heating driving winter. Heat exchangers are provided at the intermediate
mechanical floor to break the pressure in both the condenser and chilled water circuits. Adequate smoke ventilation system is incorporated following the guidelines of the local and international authorities.
• Fire fighting systems: these are backed by a storage water source of 227 cu m, which is adequate for the hazard clarification designated and in accordance with Kuwait Fire Department requirement. The site is provided with one set of working/standby electrical fire pumps with make-up jockey pump to supply the sprinkler, landing valve, hose reel and foam system. A sprinkler system protects the basement area and typical floor area while a fire hose reel system cabinets with first-aid hose reels and portable extinguishers are provided for all levels of the buildings. The building also features a wet riser system – stand pipe risers and landing valve with canvas hose in boxes provided inside the staircase for all levels of the buildings. A foam system protects the diesel generator area.
The project is owned by Salhia Real Estate Company, one of the leading real estate companies in Kuwait, which has on-site staff supervising the works. Apart from the Arraya Centre, its other projects include Salhia Commercial Complex, Salhia Plaza, Sahab Tower and Kuwait Marriott Hotels, among others.
In addition to the main contractor Ahmadiah Contracting and Trading Company, a number of subcontractors are involved in the construction of the project. These include Edrasis (shoring works) and Jasem Al Nisif (raft waterproofing), both of which have completed their jobs, and others such as Kharafi National for electro-mechanical, Mannetech/Ahmadiah for conveying system, Wuhan Linguan for external envelope works, Mannetech (ACT-ED) for façade cleaning equipment, Savema for marble supply, Alor Group for painting works and Samier Kozman for plastering works, which are currently engaged on the development.




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