Formed and scaffolded with system - PERI competence for an arched bridge

August 2009 | Oparno Motorway Bridge, Czech Republic

The 258-metre long motorway bridge spans the Oparno Valley which is located in the Bohemian area of the Czech Republic. For environmental reasons, the planners decided in favour of the challenging task of constructing a 13-field arched bridge. The reinforced concrete arch has a span of 135 metres and straddles the valley without any bridge piers and transfers the loads in the form of compressive forces into the foundations. With the help of a comprehensive PERI formwork and scaffolding solution, two separate parallel structures are concurrently being constructed in both driving directions.

In close co-operation with the Prague-based building contractor Metrostav, PERI developed a very cost-effective all-in-one solution. The Weissenhorn formwork and scaffolding specialist is using a standardised modular system with mostly rentable system components for the construction of the bridge elements. In case of the Oparno Bridge, the VARIOKIT engineering construction kit, RCS rail climbing system as well as PERI UP modular scaffold all played a key role. Their flexibility opened up a wide range of application options and areas of use. Construction of the supporting structures has therefore been very economical, optimally adapted to the individual project requirements.

Cantilevered arched supporting structure
The reinforced concrete arch is being constructed with the help of two customised formwork and scaffolding units in the form of a cantilevered construction. With this, the fresh concrete loads of the five to six-metre long arched sections are safely and reliably transferred into the previously completed load-bearing sections. During the moving procedure, hydraulic units provide the required lifting power so that work can be carried out without crane support, to a large extent, regardless of the weather. With the cantilevered construction, all adjustments needed due to the continuously changing arch geometry as well as compensation for any self loaded deformations can be carried out simply and quickly. In particular, temporary suspension measures during assembly along with the constrained points for the pier starters and the apex have been taken into consideration.

Superstructure with formwork carriage
Standardised system components taken from the PERI VARIOKIT engineering construction kit also form the basis of the span-wise construction of the double-webbed T-beam cross-sections. The 53 metre-long formwork carriage and the formwork system itself are optimally configured to form a homogeneous supporting structure. For moving around the piers, the formwork is simply folded downwards. Mobile hydraulic pumps, which also ensure that the PERI RCS rail climbing system can operate crane-independently, allow the entire striking and shuttering procedures to take place as conveniently and simply as possible.

Rail-guided climbing for the bridge piers
The RCS rail climbing system for the erection of the bridge piers ideally supplements the customised PERI modular system concept for the Oparno bridge. Whether as a climbing protection panel for enclosing those floors under construction or as climbing formwork scaffold for supporting wall formwork - the RCS modular system provides cost-efficient solutions for a wide range of applications in climbing technology. Extremely versatile in its use, here the bridge piers are constructed in concreting cycle heights of between 3.10 and 3.60 metres with RCS climbing units. The formwork scaffolding together with the climbing rail is permanently connected to the structure by means of climbing shoes during the entire climbing procedure. Drifting is therefore prevented in strong wind conditions and climbing can take place quickly and safely at all times. The VARIO girder wall formwork is mounted onto carriages complete with roller bearings and can be retracted up to 90 centimetres. The mobile RCS self-climbing concept minimizes here the costs incurred for crane-independent climbing.

A scaffold system for numerous construction tasks
As the third construction kit system used in the Oparno bridge project - along with VARIOKIT and RCS - PERI UP Rosett modular scaffolding has proved its versatility once again. PERI UP stairs and access ladders as well as working platforms serve to allow personnel to reach and assemble the temporary bracing for the arched supporting structure. A railway line running through the valley has been covered over with the help of a PERI UP protective roof construction in order to ensure that rail services continue to operate as usual during the project. In particular, the high degree of flexibility, lightweight individual components but nevertheless highly loadable steel decking support a smooth realization of the bridge project - and, due to the integrated lock against lift off, PERI UP decks are immediately secured after installation thus preventing any lateral movement.

Motorway connects Dresden with Prague
Known as the A17 in Germany and D8 in the Czech Republic, the motorway connects Dresden and Prague. This in turn is part of the pan-European corridor which extends to Budapest and then on to Istanbul. In the Bohemian Forest section alone, between Rehlovice and Lovosice, three interchanges, two tunnels and a total of 29 bridges are being constructed along the 16-kilometre route. As most of the stretch of motorway currently under construction passes through a landscape conservation area, special requirements due to strict environmental protection regulations have to be met by both the planners and contractor for the realization of this particular motorway section.

Contractor: Metrostav a.s., Division 5, Prague
Field Service: PERI Prague, Czech Republic and PERI Weissenhorn, Germany

PERI Systems In Use
- PERI UP Rosett
- RCS Rail Climbing System
- VARIOKIT

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 47 international subsidiaries and 100 stock yards around the world. The company has over 5400 employees of which 850 are engineers. 2008 revenues was 1,220 million Euros.

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This release was published on openPR.