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36 CONSTRUCTION WEEK MAY 12-18, 2012 MAY 12-18, 2012 CONSTRUCTION WEEK 37 FORMFORK FOR AIRPORTS FORMFORK FOR AIRPORTS A irports have specific formwork requirements that set them apart from other types of projects. This is because they comprise complex concrete structures requiring extensive technical design compe- tence and years of airport falsework project experience. Additional elements requiring specialist attention are formwork and shor- ing solution, immense slab thicknesses and variable ceiling heights. The main challenges involved in airports in terms of formwork are the iconic architectural designs with elaborate features, additional loading if the structure in question forms part of an aircraft apron, the fact that airports may be constructed in an excavation and tight dead- lines in terms of the project schedules. Formwork supplier RMD Kwikform has played a major role at the New Doha Interna- tional Airport in Qatar (NDIA), the first airport in the world designed to specifically house the gargantuan Airbus 380 passenger plane. It is projected to have an annual capacity of 50 million passengers, two million tonnes of cargo and parking for no less than 100 aircraft, making it one of the most advanced airports in the world. Work began in 2004, creating a construction site about a third the size of the The GCC is set to spend $90bn on airport development by 2020. This presents major opportunities and challenges for formwork suppliers Formwork on the fly city of Doha itself. For RMD Kwikform Qatar, the challenge was to provide a formwork and shoring solution to facilitate the construction of a 1,620m cross taxiway tunnel, 340m of which was to be covered to allow the construction above of the main runway. Split between east and west sections of 810m each, the project also called for a foundation and retaining walls. Before any work could begin, a staggering 11km 2 of the airport site had to be reclaimed from the sea. The resulting operation was a feat never before undertaken on such a scale, and resulted in a 13km armoured sea defence wall to. Once the dredgers had done their work, and the site was well under way, RMD Kwikform Qatar moved in to design the formwork and shoring solution. A traveller system specially designed and built for this project was used to create the retaining walls of the tunnels. The formwork was created using Superslim Soldiers and GTX crossbeams with a plywood face to the shutter- ing. Incorporated into the formwork was a set of wheels, counterbalanced by concrete blocks to offset the weight of the 9m-high formwork. Each section of the retaining wall was poured in alternate 10m and 12m sections. Each section would be tied in using high-load rapid bar ties, and then the concrete was poured. Once set, GASS Lightshore by Harsco Infrastructure deployed at Dubai International Airport.

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Page 1: ForMFork For AirPorts ForMFork For AirPorts Formwork A

36 construction week may 12-18, 2012 may 12-18, 2012 construction week 37

ForMFork For AirPorts ForMFork For AirPorts

Airports have specific formwork requirements that set them apart from other types of projects. This is because they comprise complex concrete structures

requiring extensive technical design compe-tence and years of airport falsework project experience. Additional elements requiring specialist attention are formwork and shor-ing solution, immense slab thicknesses and variable ceiling heights.

The main challenges involved in airports in terms of formwork are the iconic architectural designs with elaborate features, additional loading if the structure in question forms part of an aircraft apron, the fact that airports may be constructed in an excavation and tight dead-lines in terms of the project schedules.

Formwork supplier RMD Kwikform has played a major role at the New Doha Interna-tional Airport in Qatar (NDIA), the first airport in the world designed to specifically house the gargantuan Airbus 380 passenger plane. It is projected to have an annual capacity of 50 million passengers, two million tonnes of cargo and parking for no less than 100 aircraft, making it one of the most advanced airports in the world. Work began in 2004, creating a construction site about a third the size of the

The GCC is set to spend $90bn on airport development by 2020. This presents major opportunities and challenges for formwork suppliers

Formwork on the fly

city of Doha itself. For RMD Kwikform Qatar, the challenge was to provide a formwork and shoring solution to facilitate the construction of a 1,620m cross taxiway tunnel, 340m of which was to be covered to allow the construction above of the main runway. Split between east and west sections of 810m each, the project also called for a foundation and retaining walls.

Before any work could begin, a staggering 11km2 of the airport site had to be reclaimed from the sea. The resulting operation was a feat never before undertaken on such a scale, and resulted in a 13km armoured sea defence wall to. Once the dredgers had done their work, and the site was well under way, RMD Kwikform Qatar moved in to design the formwork and shoring solution.

A traveller system specially designed and built for this project was used to create the retaining walls of the tunnels. The formwork was created using Superslim Soldiers and GTX crossbeams with a plywood face to the shutter-ing. Incorporated into the formwork was a set of wheels, counterbalanced by concrete blocks to offset the weight of the 9m-high formwork.

Each section of the retaining wall was poured in alternate 10m and 12m sections. Each section would be tied in using high-load rapid bar ties, and then the concrete was poured. Once set,

GASS Lightshore by Harsco Infrastructure deployed at Dubai International Airport.

Page 2: ForMFork For AirPorts ForMFork For AirPorts Formwork A

38 construction week may 12-18, 2012

ForMFork For AirPorts

may 12-18, 2012 construction week 39

ForMFork For AirPorts

RMD Kwikform’s dedicated on-site engineers were quick to react to design changes.

the shuttering could then be untied, released, cleaned and easily wheeled on tracks to pour the next section of the wall in a continuous cycle. All this meant that the RMD Kwikform equipment and panels only had to be craned in once, constructed once, and then craned off-site when the tunnel was complete.

Ahmad Deeb, project engineer: civil at Consolidated Contractors International, com-mented on the impact the traveller system had on the day-to-day running of the build. “The real benefit comes in the cycle time. On this project, the cycle time has been reduced by almost a week by simply eliminating the need for a crane. On-site safety is very important to us. The traveller system we have used on the retaining walls shows the ability of RMD Kwikform Qatar’s designers to meet tough targets without compromising safety.”

The challenges did not end there. The curved section of the wall needed to be formed using the same shutter work used on the rest of the retaining walls. To achieve this, a specially-made beam section was added to the GTX cross-beams to create the correct curvature in the plywood face of the shuttering. This created a seamless finish to the 1,620m tunnel that will be used to transport vital equipment and service the runway of the airport itself.

Once the retaining walls were in place, the 340m covered tunnel section became an imme-diate priority. This needed to be in place to allow above-ground building works to move at a pace so that they would be completed on schedule. The 9m-high reinforced concrete walls that made up either side of the tunnel had to be constructed with a covering that could be rapidly constructed to a high-quality finish.

The solution lay mainly in the versatile Alshor Plus shoring system. An Alshor Plus table, com-plete with quick-release mechanism, was used to form the soffit. The lightweight aluminium design meant that, once an area of the cover section had been poured and cured, it could be quickly and easily released and safely moved to pour the next section along. Any variation in height could also easily be accommodated by making millimetre adjustments to individual Alshor Plus jacks.

Another staple of this largescale construc-tion environment, RMD Kwikform’s heavy-duty Megashor was used to support the roof structure, while the Alshor Plus system was continually moved along the length of the tunnel. This combination of the two systems

Harsco’s airport reference projects include Terminal 3 at Dubai International Airport, a 1km-long terminal building that is one of the largest in the world, built by the Al Naboo-dah Laing O’Rourke JV. The arrangement of floors includes varying ceiling heights and open voids, making the concrete structure complex to design, construct and plan. The upper slab also forms part of the aircraft apron, and has to support the weight of waiting planes.

The huge basement area was constructed in an excavation 800 x 700m and 20m deep. A curved steel roof is suspended over a complex concrete frame. The sub-structure accommo-dates an arrivals hall, departures halls, lounges, restaurants, shops and parking. Terminal 3 was part of a $40.1bn expansion project to increase the capacity of the airport to 70 mil-lion passengers a year. “Harsco worked with Al Naboodah Laing O’Rourke JV to design and develop a forming and shoring solution

to meet the very tight deadline for comple-tion. The floor slab was a considerable size, over 1,000,000m2, with a thickness of up to 2.2m and ceiling heights of up to 16m,” says

Newson-Smith. “GASS aluminum shoring system was selected as the most appropri-ate cost-efficient solution. Over a 30-month period, Harsco supplied over 5,000 tonnes of GASS and ancilliary products.”

Newson-Smith comments that: “Harsco Infrastructure has regularly worked on proj-ects for NDIA. In the past, it has undertaken to provide the design and supply of formwork systems for the WCT/Gamuda JV. A special travelling steel form was manufactured for casting concrete walls and cover slabs on the airport services culverts for use in a rapid con-struction cycle.”

Presently it is supplying contract scaffolding to Linder for re-furbishment of the lounges in a nine-month project that will be completed in December 2012. “Cuplok and contract labour have been provided to create a landing plat-form for men and materials in area CP77,” says Newson-Smith.

“We needed a formwork and shoring supplier that could handle the requirements of a project on this scale and still deliver on-time.” Ahmad Deeb

11km2The land that had to be reclaimed before any work at NDIA could begin.

1,620mLength of cross taxiway tunnel, of which 340m was covered to allow main runway construction.

allowed the Alshor Plus tables to be moved every three days. Megashor would then stay in place to support the slab in the final cur-ing stages for a further 18 days, representing a considerable time-saving.

“We needed a formwork and shoring sup-plier that could handle the constantly-changing requirements of a project on this scale and still deliver through to completion on-time. Given the importance of the taxiway tunnel, any minor delays would have had a knock-on effect later in the project. The fact that RMD Kwikform Qatar’s dedicated on-site engineers were quick to react to changes in both the design and programme time means we ulti-mately made the right choice.”

Another formwork company supplying spe-cific solutions for the airport sector is Harsco Infrastructure. Harsco is no stranger to airports, having worked on such high-profile airport projects as Terminal 5 at Heathrow and Cep Lak Kok in Hong Kong, says regional marketing manager: MENA and India Fiona Newson-Smith. The latter was the biggest construc-tion project in the world at the time, twice the size of Heathow, with the airport opening for commercial operation in 1998. The 2km-long project required 10,000m3 of concrete to be cast a week to a F5 finish.

Harsco Infrastructure’s reference projects include Dubai International Airport.

RMD Formwork developed customised solustions for NDIA.