News

Released: 24. 10. 2005

On Monday, October 24 a singular technical operation was brought to completion on the construction site of the D8 freeway section near the frontier with Germany – Metrostav's people together with VSL Systémy (CZ) Ltd. have pushed forward across the valley the last segment of a bridge structure having 356 m in length, constructed of transversally as well as longitudinally reinforced concrete. The structure spans the Rybný potok (Fishbrook) Valley as high as 50 meters above the valley floor. The structure which had to be brought in motion at this last stage of advancement was a colossus over 19 thousand tons in weight. Its trajectory of advance had to be controlled to millimeter precision.
This unique building technique as adopted mainly to save time. In fact, the construction of the Rybný potok bridge was delayed because of a number of appeals lodged by its opponents and it would have been impossible to implement on time, before the end of 2006 which was the deadline anchored in an international agreement, the original project plan that involved two separate bridges for the two directions of travel.
Metrostav joined by the designers bureau (SHP Brno) proposed to merge the two bridge bodies into one, which was then built of concrete and pushed forward in stepwise fashion, in segments of 31,1 by 30 m in size. With these parameters the project is an absolute rarity. Handling a burden this heavy and cumbersome, of complex design, is nearing the very limit of what is technically possible.
It was the very first time ever since Czech Republic came into existence that the sliding shuttering technology was adopted on this transport infrastructure to the bridge pillars. This has made it possible to put in place 189 linear meters of pillar work within a mere 52 days, to the quality as required by the investor. The sliding shuttering required was supplied by Omega Teplotechna Corp., in cooperation with Gleitbau Salzburg, GmbH. The technique has been used elsewhere in the world for bridges on tall pillars. It requires not only a high degree of precision but also specially prepared concrete mixes and perfect interplay of the work gangs.
Thanks to the technologies chosen, the period which elapsed from the date of placing the first batches of concrete in the foundation structure until the last advance of the supporting structure of this freeway bridge was cut to no more than 7 months. Now the builders have plenty of time to cope with all the finishing work required to have the bridge complete with all accessories and to open it for traffic, to the required deadline. Moreover, this has expedited the construction without incurring any additional investment costs.

Metrostav has had a rather substantial experience already with the sliding advance technology. For example, a similar method was adopted to construct the recently completed railroad bridge at Karlovy Vary, where a bridge having 44 meters in length and weighing 360 tons was assembled in a location 26 meters away from its intended position, and then moved by sliding motion to its operating position. Two subway tunnels under Vltava river connecting the city districts of Holešovice and Troja were built using an entirely unique method. The two tubings of 168 m in length were first constructed of concrete in a dry dock on the riverbank, whereupon they were pushed forward to finally become lodged in position in ridge dredged in advance at the river bottom.



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For more information contact:
Frantisek POLAK
spokesman Metrostav a.s.
Tel.: +420-266 709 294
E-mail: polakf@metrostav.cz