Decks, slabs, beams and climbing brackets

Formwork contractors are uniquely positioned to take advantage of the diverse types of construction underway across the Middle East. Christopher Sell reports on how projects ranging from athletics stadiums to hydropower plants are taking shape.

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By  Christopher Sell Published  December 16, 2006

|~|150prod200.gif|~|RMD Kwikform is supplying 14,000 tonnes of equipment to the Dubai Mall project, including 130,000m2 of slab and beam support and 20,000m2 of wall formwork. On completion of the development, the formwork programme will have been 28 months on a project that will use more than 650,000m3 of concrete.|~|With construction booming and contract schedules tightening across the region, contractors are leaning more and more to building solutions that offer faster results, while placing less demand on their labour force. This has, unsurprisingly, attracted the world’s major players in the formwork industry to establish themselves in the Middle East, in the hope of capitalising on the increased work on offer. Paschal Concrete Forms opened a Dubai branch in 2004, and the firm is now supplying formwork to more than 25 developments, including the Golden Mile, Citadel Tower at Business Bay, Acico Tower at Twin Bay and the Al Khali Tower. Further afield, Paschal is providing its formwork solutions for some major ongoing projects in Qatar and Bahrain, which include the Scada Water System at the NWCC building near Doha International Airport and a 52-storey tower building in the Diplomatic Area of Doha, Qatar. With strong competition being faced in all the regional markets, contractors are keen to reduce construction time and manpower as well as avoid material wastage. Paschal’s panels are manufactured using 6mm frames of special non-corrosive steel, while the surface of the panels is covered by high quality birch plywood with a phenolic coating of 220gm/m2. The edges of the plywood are protected by a steel frame and the gap between them is filled with a special sealant, meaning that they can be re-used up to 250 times. RMD Kwikform, one of the region’s leading formwork specialists is working on the Dubai Mall – the world’s largest shopping centre. A partnership of Dutco Balfour Beatty Group and an Al Ghandi/Consolidated Contractors Company joint venture, the project is scheduled for completion by April next year. Andy Teesdale, project manager, RMD Kwikform UAE, explains that the company has 14,000 tonnes of equipment on site, composed of 130,000m2 of slab and beam support and 20,000m2 of wall formwork. By the time the last concrete pour is made in April next year, the completion time for the formwork programme will have been 28 months on a project that will use more than 650,000m3 of concrete. But demand for formwork technology is not just limited to commercial buildings; regional infrastructure projects are also benefiting. Peri is using its high formwork for some major infrastructure projects in the Middle East, such as a mega water treatment facility in Jordan and a dam project in Egypt. Nearing completion, the wastewater treatment facility is expected to commence operations early next year. Eight circular aeration tanks plus eight final settling basins, with diameters of 65m and 54m respectively, were constructed on the premise of maintaining a very tight schedule. This required 5,500m2 and 1,000m2 slab formwork to be maintained at all times. A girder wall formwork was used for the walls, which meant all construction units, and applications could be cost-effectively produced using just one flexible system. The six and nine metre-high walls were divided into two or three vertical casting segments with the higher sections formed by placing Vario formwork on type-tested CB climbing brackets. With such hydro-engineering projects, where demands on impermeability are increased, Peri utilised its DK tie system to ensure water tightness. This method consists of reusable sealing cones that are fitted to the spacer on both sides and enclose the tie rod. After striking has taken place and the required concrete strength has been reached, the cone is removed, after which sealing of the points is carried out through special Peri concrete cones that are tightly bonded in place with a sealing compound. The purification plant has been built as a BOT project by the Morganit Group – after a 25-year operating period, the plant will become the property of the Jordanian government in 2028. Peri is also involved in constructing the Naga Hammadi barrage on the river Nile. Developed by a consortium of Bilfinger Berger, Vinci and Orascom, the $285.8 million project will, once complete, improve the water and electricity supply to the Upper Egypt region. Due to open in 2008 following a four-year construction programme, it consists of a 64mW hydroelectric plant, a seven-gate weir facility for water level adjustment as well as two 170m-long navigation locks of 17m width. The main columns reached heights of 138m and 17.5m thick with intermediate walls of thickness of 1m and 4m. The structure itself, which reaches heights of 30m, required 380,000m3 of reinforced concrete. Doka, while best known for its high-profile work on the Burj Dubai, continues to innovate formwork techniques on a number of other projects. Of particular interest is a new athletics stadium in Kuwait, the Jaber Al-Ahmed International Stadium. Scheduled to open this month, the stadium required the casting of 52 hollow wall piers from in-situ concrete. Stepped beams cantilever out as much as 50m from the tops of the wall, rising to a height of 65m. They carry the roof construction and the grandstands, and are stiffened in the horizontal by connecting cross-beams that are made of concrete. For this, Doka supplied a formwork solution that required no falsework support. A special cantilever formwork was developed which can be ‘jumped’ in a similar way to a climbing formwork, thus ensuring large savings in terms of falsework and labour costs. Unlike a classic climbing formwork for vertical walls, this system has to sustain not only its own dead weight and the wind loads, but the weight of the fresh concrete and transfer these loads into the previously cured section. In each set of formwork, elements of Top 50 large-area formwork are set up on two steel girders. These are fixed in two climbing shoes on the underside of the stepped beam. At the top, the whole system is back-stayed with 10m long tie-rods, each with a failure load of 100 tonnes, which begins at the outermost edge of the formwork and end in the back-stay unit. This is made up of steel girders that are anchored in the concrete at the top of the stepped beam, and these transfer the 70-tonne load of the fresh concrete into the previously finished section. Adel Hamdy, project engineer explains the system provides far better speed in the build: “On the stepped beams, we’ve been able to manage entirely without time-consuming falsework, thanks to the climbing formwork solution,” he says. Using this method, Doka claims the climbing cantilever formwork results in very big savings of time and equipment. The stepped ones grow by one 5m-long segment each week. After 38m, the stepped beams – which have cantilever lengths of up to 50m need to be restressed.||**||

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