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| Formwork solutions for fast building progress  The Bellevue Towers residential project near Seattle, currently under construction, comprises of two 137-metre high towers: the north and south towers with 42 and 43 floors respectively. The concrete shell should be ready in spring 2008 and residents can begin moving into the apartments in the autumn. With the comprehensive PERI formwork solution, contractors Hoffman Construction are in a position to finish a complete floor in only six days. For this project, PERI ACS and RCS climbing formwork systems along with the VARIO wall formwork and SKYDECK slab formwork systems have been carefully matched. Due to the stringent system-related safety levels and the complete enclosure of the upper storeys, construction work has been able to be carried out extremely safely resulting in fast building progress.The 3.12 metre high walls of the reinforced concrete core and the storey slabs of both towers are concreted in one pour. This shortens the cycle times and minimizes the reinforcement work. For this, the PERI ACS self-climbing system (ACS = Automatic Climbing System) and the modular PERI RCS rail climbing system (RCS = Rail Climbing System) work on the building cores simultaneously and without the need of a crane. Whilst the VARIO wall formwork and the central placing boom in the inner shafts are moved with the help of three ACS self-climbing units, the RCS construction kit system serves as the basis for the core exteriors. Here, the climbing rails are guided through narrow openings in the SKYDECK slab formwork and the floors under it. For the angular and variable building ground plan, the fact that the RCS standard solution could easily be adapted to meet the project-specific requirements was a tremendous advantage. Thus, regularly-occuring wall breaks could simply be climbed over without the need of any time consuming conversion work. The SKYDECK panel slab formwork with the lightweight individual components and logical assembly sequence, guarantees substantial time advantages when forming the floor slabs. Consequently, a tight 6-day cycle can be maintained through the use of the ACS and RCS systems. In order to ensure high labour productivity and safety even at large heights, the PERI RCS climbing protection panel completely encloses the building edges of the three top storeys at any one time. In addition to its function as a safety barrier against falling, it also provides reliable protection against wind and weather. Through the combined provision of different climbing applications as a climbing protection panel and formwork scaffolding with a construction kit system, a positive side-effect is achieved: for each Bellevue tower, only two mobile hydraulic pumps with four cylinders respectively are required in order to bring formwork and protection panel to the next section with efficient use of material and saves on expensive crane operations. In the process, the mobile RCS self-climbing devices and hydraulic pumps ensure crane-independent climbing with minimum expenditure – with this, self-climbing technology is also cost-effective for structures with lower heights. The self-climbing devices have a lifting capacity of five tonnes. Due to their low weight, they are extremely easy to handle and can be quickly installed by means of quick-release mechanisms. In both cases - without and occasionally with crane support - the RCS units are guided safely and reliably on the building edges using climbing rails and shoes. The assembly can take place - depending on the building geometry and requirements - at the slab edge or on the wall itself. write your comments about the article :: © 2007 Construction News :: home page |