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| Renovation of listed train shed roofs during ongoing daily operations  On the basis of the PERI solution featuring transversely and longitudinally movable working and safety platforms, refurbishment work for the glass roofing on the five-span train shed of the Wiesbaden central station has been carried out very quickly and without significant interference to rail operations and passenger movements throughout the station. Thanks to the mutually supportive cooperation from the planning phase onwards between the Ed. Züblin AG / Eiffel Deutschland Stahltechnologie consortium, scaffolding contractor Paul and PERI engineers, all specified deadlines have been met. The use of standardized, rentable system components from the extensive scaffolding and formwork product ranges has also played an important role here.The impressive looking station building of the historic, listed main railway station in Wiesbaden dates from the time of Kaiser Wilhelm II and was extensively refurbished and modernised almost ten years ago in the first phase of redevelopment. Since April 2011, the glass roofing which spans the terminal station´s platforms has been renovated at a cost of € 35 million. During ongoing daily operations, the glass and steel roof structures with different widths have been gradually replaced. Mobile PERI UP platforms serve here as an extremely effective protective roof and assembly constructions which can also be re-positioned very quickly. The five shed roofs, with spans ranging between 35 m and 51 m, have been replaced in sections. A 190 m long protective roof construction with spans between 7.50 m and 12.50 m straddles the rail tracks of the corresponding hall. Normal station operations with around 30, 000 passengers and 500 train movements per day have been virtually unaffected during the entire refurbishment work. Only when assembly work has been required on the scaffold have those rail tracks affected been closed for a short period. In order to ensure that the time required for moving the protective roof is kept to an absolute minimum, PERI engineers designed mobile platform units. At a height of almost 7 m, these can be manoeuvred to the next rack section by hand without any mechanical support – longitudinally by means of a trolley and laterally using roller blocks. Transverse and longitudinal moving of the units is carried out through the use of rails which means they are secured on the sides at all times. A total of 66 platforms with standard 3.00 m widths were delivered to the jobsite already preassembled and then lifted through a partially open section of roof with a crane and set down on the steel walers of the PERI UP supporting structure which are being used as rails. From this point, the units are moved to their respective specified positions without further crane support. Safe access for the construction crew and the scaffold assembly team is provided by 75 cm wide aluminium and 1.00 m wide steel stairs respectively of the PERI UP scaffolding system. These are fully integrated into the supporting structure of the platforms, likewise the decking on the top level which serves as a pathway in order to quickly move the platforms. For the planning of the PERI UP load carrying system not only were the rail tracks to be kept open but suitable walkways for pedestrians also had to be taken into consideration with sufficiently wide passage widths. In addition, the scaffold sub-structure carries the vertical loads as well as horizontal loads from the platform as anchoring to the steel components which were to be refurbished was not possible due to structural reasons. A further task for the Weissenhorn scaffold planners was to find a solution for bridging the retail outlets and kiosks. Adapted to meet local conditions, shear frames comprised of system components or high load-bearing steel main beams taken from the PERI HD 200 heavy duty prop programme reliably transfer the loads even for large spans of up to 10 m and carry these into the supporting structure. Here, the legs of the PERI UP scaffold can be bundled together by means of short 25 cm ledgers and are thus optimally adapted to suit the load concentration. Furthermore, the metric grid arrangement provides sufficient flexibility for any geometrical adjustments that had to be made regarding railwayrelated plant along with technical installations of the retail and gastronomy facilities. A big advantage for the implementation of the construction work is that PERI engineers along with the construction and scaffolding contractors had already taken into consideration the time-critical moving procedures in advance and could thus be optimized accordingly. In a socalled mock up – a field test on PERI's Weissenhorn premises – the assembly process as well as lateral and longitudinal moving of the platforms could clearly be demonstrated. Furthermore, the requested protective effect could be proven though a range of drop tests. In addition, the stable construction with trapezoidal profiles and formwork panels is designed for live loads up to 5 kN/m² as well as point loads from the mobile scaffolds. write your comments about the article :: © 2012 Construction News :: home page |