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| Complex construction in historical surroundings  Located in the northern part of Dresden, a spectacular Military History Museum development is taking shape – an eye-catching structure from the renowned architect, Daniel Libeskind. His concept, split between the old and the new, was the eventual winner of the architectural design competition: the former Saxonian arsenal building restored to its original state and supplemented by an integrated, modern new structure. A bold, almost 100-metre long wedge construction made of reinforced concrete complete with a 30-metre high steel and glass wedge tip forms an architectural incision through the spatial arrangement of the old building. In addition, the support-free extension provides a wonderful panoramic view of the historical centre of Dresden.The architectural concrete walls are inclined in different directions, a design very characteristic of star architect Libeskind. The absence of perpendicular walls and right angles imparts a special kind of spatial perception for visitors but also represent an especially difficult challenge for the actual realization. For the construction progress and, in particular, the formwork concept, two further factors played an important role: the tight space conditions due to the integration in the existing structure as well as the fact that load transfer at any time during construction were not were allowed to affect the structural fabric of the old building in any way. In October 2008, the museum celebrated its topping out after only a two-year construction period – a masterly performance of all those involved when one considers the complexity of this building project. Already during the offer phase, the Bautzen-based construction company Hentschke Bau GmbH and PERI engineers from Cottbus worked closely together to develop a concept which finally led to the award of the contract and thus professional and expert construction of the concrete frame. The formwork and scaffolding solution was based on customer-owned PERI systems as much as possible and supplemented through project-related system components from the PERI rental park. In addition, the entire engineering requirements, i.e. the formwork and scaffolding planning, static calculations as well as the creation of the pre-assembly drawings originated from PERI. Realization took place using Hentschke formwork construction complete with the very latest equipment, and on site through the very experienced team. Thus, the jointly-developed total package, paired with flexible PERI system equipment and punctual deliveries, has led to an impressive result. Requirement for the wall sections formed using concrete cast in situ was the unusually high architectural concrete quality level due to the particularly high significance of design considerations. In a so-called "architectural concrete team", representatives of the architect, construction company, formwork manufacturer and planners as well as the concrete supplier monitored and coordinated the construction work. Thus, in order to achieve the highest architectural concrete class, the formwork technology and concrete formulation could be optimally matched with on-site concreting and compacting operations. Here, both Hentschke and PERI could draw on extensive experience gained from similar challenging projects – an important requirement for successful jobsite planning and execution. As the architectural concrete walls can neither be milled nor drilled at any point in the future, all openings and, in part, enormous display cabinets had to be considered in advance. The variable VARIO GT 24 wall formwork system provided the ideal basis for constructing the complicated layouts with wall inclinations ranging between three and 39 degrees. The system can be easily adapted to suit each particular project and individual requirements. Thus, for example, the girder spacing of all the VARIO wall formwork elements was reduced to 25 centimetres in order to minimize possible deformations. The distinctive features of the Dresden museum project made it necessary, however, that the formwork had to be planned individually and often three-dimensionally for almost each structural component which then had to be specially mounted. For the higher, inclined wall structural elements, climbing units were formed using components taken from the PERI SKS single-sided climbing system and VARIO girder wall formwork. On the one hand, this solution is used for single-sided climbing with massive structural parts whilst, on the other, the museum´s internal walls with forward and reverse inclinations up to 40 degrees could also be concreted. Without requiring any special measures, additional concrete loads or lifting forces were safely transferred into the building. With a specially-designed lifting transverse comprised of PERI system components, the construction crew was always able to attach the SKS/VARIO moving units to the crane exactly in the respective centre of gravity. In this way, the different inclinations could be taken into consideration. Due to static reasons, all walls and slabs had to be fully supported until construction of the concrete frame had been completed. In this respect, PERI raised formwork units were used with SRU steel walers and SLS heavy-duty spindles connected by UK 70 universal couplings. Already during concreting, all loads were reliably transferred into the building. Lightweight but nevertheless strong load-bearing MULTIPROP aluminium slab props and HD 200 heavy-duty props provided a cost-effective load-carrying concept for heavy loads and large heights. This was in turn supplemented through the PERI UP modular scaffold system for heights of up to 17 metres and was mounted to form load-bearing internal scaffolding for supporting the external walls as well as the slab formwork. Due to the modular structure and the metric grid dimensions, geometrical adjustments could be carried out on the different, often inclined contact areas. write your comments about the article :: © 2009 Construction News :: home page |