City Tunnel Malmö, Sweden

Cost-effective combination
PERI formwork carriage construction and rentable system parts

The Oresund connection between Sweden and Denmark, a combination comprising both bridge and tunnel structures, was officially opened in July 2000. As a result, the cities of Malmö and Copenhagen were brought much closer together through this road and rail development. With the new Malmö city tunnel, the rail connection should be accelerated even further. The key element of the 9 billion Swedish krone project is the eleven kilometre-long direct connection between the Öresund bridge and the Malmö main railway station as well as the new, underground station at the existing station. Also included in the development are two additional railway stations in city centre and on the outskirts of the city and whose completion is planned for 2011.

With the entrance area in the south and station extension in the north, the first construction sections are already are in full swing. For this, formwork and scaffolding specialists, PERI, provided the most cost-effective solution. In a Swedish-German collaboration, PERI engineers developed an intelligent combination consisting of project-specific formwork carriage constructions and rentable PERI system equipment for the challenging tasks.
The tunnel section for the railway station at Malmö main station is being built using the cut-and-cover method, and varies considerably in both width and height. On both sides, the twin rectangular cross-sections have internal widths of up to 21 metres as well as heights between 7.20 m and 9.85 m. The semi-monolithic method is carried out in the so-called trough construction procedure. Here, the bottom plate and walls are concreted in one pour with the slab completed separately afterwards. A maximum level of watertightness is achieved by not having any construction joints in the area of the bottom plate.

The comprehensive PERI formwork solution for the twelve metre-long concreting sections consisted of the variable PERI VARIO GT 24 girder wall formwork on two formwork carriages for the casting segment in advance, a specially designed PERI VARIO solution for the elliptical reinforced concrete columns along the tunnel centre as well as the two slab formwork carriages which subsequently followed. As the bottom plate and external walls were concreted in one working cycle, the formwork carriages for the VARIO wall formwork are designed in such a way that moving can take place with different heights for the concrete sub-base at the front and on the bottom plate at the rear. Generously-sized working platforms allow formwork operations to be carried out safely along with an efficient concreting process. With the PERI UP Rosett modular scaffolding, the contractors had an appropriate system at their disposal in order to quickly realise reinforcement scaffolding and scaffold staircases, and be in a position to adapt to the various heights on the spot.

Two separate PERI slab formwork carriages ensure that the up to 1.10 m thick tunnel top slab is subsequently cast at the same operational speed. A formwork carriage is comprised of two support frames with a hydraulic raise and lowering mechanism along with a sectional row of HD heavy-duty props. For constructional site traffic, a 4.70 m wide passageway is available for problem-free access. For the different widths in the widened areas, continuous adjustment is carried out via telescopic girders whilst easy and simple height compensation of up to 2.60 m takes place by means of hydraulic cylinders. The PERI solution also takes into account the vaulted sections in the external areas and the beam formwork in tunnel centre. PERI ST 100 stacking towers and MULTIPROP 625 slab props provide a quickly assembled and load-bearing sub-structure between the central columns for the 0.60 to 3.15 m high beams. Site crews are able to complete both casting segments – bottom plate/wall and slab - in 10-day cycles.

Around 1.5 kilometres of the southern entrance area will also be constructed by means of the cut-and-cover method. The two parallel tunnel constructions have rectangular cross-sections with 7.00 m to 9.00 m internal diameters and 7.20 m to 7.70 m headroom and will likewise be cast using the semi-monolithic method but in this case with walls and slab in one pour after the bottom plate has been concreted. For this, PERI engineers have designed two formwork carriages with a hydraulic raise and lowering mechanism as well as integrated stopend formwork which also accommodates the installation of water bars. The PERI construction takes into consideration not only the varying wall and slab thicknesses but also the different cross-sectional dimensions regarding height and width. In the widened areas found in the tunnel portal, the slab elements of the formwork carriage can be telescoped hydraulically from seven up to nine metres. The articulated wall elements are attached to the slab girders and folded by means of hydraulic cylinders. Internal and external formwork can be continuously adapted to the different wall heights. The two PERI formwork carriages are used in parallel and are moved to the next casting segment by means of heavy-duty rollers positioned on rails. With this construction method, both tunnel cross-sections can be realised extremely efficiently in 15-metre sections.

In addition to the assembly instructions available for all PERI standard equipment, a separate operating manual was created for the special project-related PERI formwork carriage. This ensures simple and, above all, safe operations on site.

For more than 37 years, PERI has been a successful partner to many construction companies around the world. With 42 foreign subsidiaries and 70 efficiently organized stockyards, the formwork and scaffolding manufacturer provides its customers with know-how, system equipment and related services. In traffic route construction, too, PERI formwork and scaffold systems as well as its engineering capabilities are considered as pointing the way ahead for the entire industry. For tunnel and bridge construction, PERI has published two detailed handbooks which provide a comprehensive overview of each respective formwork technology.

Project Details

Client:
NCC Construction Sverige AB (Malmö C Nedre, E101)
MCG Malmö Citytunnel Group (Entrance Area E201);
Bilfinger Berger AG, Per Aarsleff A/S, E. Pihl & Son A.S.

Field Service:
PERI Weissenhorn (www.peri.de)
and PERI Halmstad (www.periform.se)

PERI GmbH
Formwork and Shoring
P.O. Box 1264
89259 Weissenhorn
Tel.: +49/ 73 09/ 9 50-0
Fax: +49/ 73 09/ 9 51-0
www.peri.de
info@peri.de

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Please send a copy to the PERI Editorial Office.

PERI Editorial Team
Tel.: +49/ 73 09/ 9 50-1 18
Fax: +49/ 73 09/ 9 51-1 18
redaktion@peri.de
http://www.peri.de/ww/en/pub/presse/nov_01_06.cfm

PERI was founded in 1969 and is today one of the leading providers of formwork and scaffolding systems. Along with the headquarters in Weißenhorn, Germany, the company has 42 international subsidiaries and 70 stock yards around the world. The company has over 4.000 employees of which 700 are engineers (as of 2005). 2005 revenues were more than 760 million Euros.

This release was published on openPR.