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| Accelerated and safe construction with system components  The Rotterdam-based architect, Rem Koolhaas, has given his high-rise ensemble a huge "jolt" – and as a result has placed high demands on the construction work. Therefore, the supporting structure concept for realizing the cantilevers at a height of 86 m is an essential part of the comprehensive PERI overall solution. De Rotterdam will be the largest building in the Netherlands – situated in the immediate vicinity to other architectural highlights such as the Erasmus Bridge by Van Berkel & Bos, the inclined high-rise building by Renzo Piano and the World Port Center by Sir Norman Foster. Once completed, the 150 m high multi-storey ensemble on Rotterdam´s Wilhelminapier peninsula on the south bank of the river Maas, will consist of three complex designed towers standing side by side and connected to each other. The West Tower has 45 residential levels, the 41-storey Central Tower is designed to be used as office facilities only whilst the 43 floors of the East Tower feature both office space as well as a hotel tract. In total, around 250 apartments, 280 hotel rooms and 60,000 m² of office space will be realised. The five-storey base section of the building has retail stores, restaurants, conference rooms and a fitness centre – as well as three parking decks on the ground floor and two basement levels.A native of Rotterdam, renowned architect Rem Koolhaas has given his high-rise complex a huge "jolt" – shifting the upper half of the building to the side with a horizontal offset to the west and north. In so doing, at a height of 86 m, the 24th and 26th floors respectively along with the remaining upper storeys cantilever outwards up to 9 m. The construction site crew of Ed. Züblin AG, Stuttgart, has vast experience in realising high-rise buildings and the structural work is scheduled to be finished in early 2013 whilst the de Rotterdam CV project group plans to have all construction work completed by the end of the year. The rapid construction progress is supported through the use of comprehensive and ideally combined PERI system solutions. In particular, the supporting formwork solution for the cantilevered sections is an important component of the PERI overall concept. For realising the huge cantilevers at the great heights, PERI engineers developed a supporting formwork solution on the basis of the VARIOKIT engineering construction kit. For this, rentable system components are being used to a large extent, supplemented by a project-specific bracing construction. The flexible arrangement of the shear frames is carried out here whilst taking into account the respective geometry and loads of the structure as well as the range of mounting parts through to the masts of the tower cranes positioned in the building itself. For dimensioning the beam heights in the West Tower, transferring the large loads from the 8.88 m cantilevers for two complete floors of the building and the low 3.52 m height of the storey below, had to be taken into consideration. For the Central and East Towers, a double-storey can be used for this purpose – here, the supporting formwork solution not only serves for transferring the loads from the cantilevers but also as a supporting structure between the floors. Extensive PERI know-how is used to good effect especially in the beam extensions when the inherent load-bearing capacity of the building has been reached. The fact is that due to reasons of space, the shear frames cannot be simply retracted and disassembled within the storey itself without requiring direct crane support. For this purpose, the construction site crew is using the PERI lifting carriage that is normally used in connection with SKYTABLE large slab tables. The advantage of the PERI method – which was developed in and has been used for many years in North America – is that the shear frame is pulled horizontally from the building by means of a crane lift, a special chain block system and rear carriage. With the RCS P climbing protection panel from PERI, the two topmost floors under construction are completely enclosed each time. As a result, site personnel are prevented from falling at all times and protected from strong winds at great heights – this means that forming operations are accelerated and work performance is greatly enhanced. Züblin requires only eight days for one complete standard floor. Already during the planning phase, the geometrical changes of the towers were taken into consideration so that those protection panel units affected by the offset could be moved to other sections without requiring any extensive modification work. The RCS solution demonstrated its high level of flexibility in the areas close to the slab edge where anchoring was not an option. In this situation, too, the slab shoes are securely fixed and ensure fast climbing procedures due to the continuing rail guidance. With the SKYDECK panel slab formwork, floor slabs can be formed without the need of a crane. System components made of aluminum to facilitate the transport and, in particular, shuttering and striking can be carried out manually. The systematic and therefore easy to-understand assembly sequence accelerates the construction processes and also ensures that time requirements can be accurately estimated. In addition, through the use of the drophead and the possibility of early striking, this also reduces the amount of panels and main beams required on site. For the floors in the base section, the systematic assembly sequence and the high degree of safety for each standard bay has already been achieved using the SKYDECK platforms and the cantilevered 375 SLT main beams, also at the slab edges. For the large supporting heights reaching over several floors, the construction crew have combined SKYDECK with the MULTIPROP load-bearing system. The lightweight aluminum individual props can be vertically connected to each other by means of the MULTIPROP connector – and joined together using MULTIPROP frames to form extremely stable shoring towers. De Rotterdam is encircled on all sides – longitudinally between the road and the Maas river as well as between two neighboring buildings at the ends. The narrow construction site therefore has very limited storage space. As a result, PERI supplied the RCS protection panel units and VARIOKIT shear frames already pre-assembled to the construction site. This means that these are lifted directly from the truck by crane and taken immediately to the designated place of use. This saves valuable crane time; in particular, no additional storage facilities and assembly area are required. write your comments about the article :: © 2012 Construction News :: home page |