Strand Tendons for Interstate Bridge over the Pipa River
Currently the Portuguese interstate network is being extended north of Lisbon. A principal element in this new A10 interstate is the bridge near Arruda dos Vinhos, about 20 km north of Lisbon. In that area the new interstate passes through the plain of the rivers Ribeira da Laje and Rio Grande da Pipa.
In this connection, special focus is placed on the protection of the sensitive ecological equilibrium along the courses of the rivers. Since the area with the embedded rivers Ribeira da Laje and Rio Grande da Pipa is highly uneven, construction of a bridge is the most economical solution.
The interstate employs two lanes in each direction. The 1,319 m long structure consisting of two parallel single bridges rests on 14 piers with a height of up to 48 m. As a result of the length of the viaduct there will be considerable span widths of up to 90 m between the piers, requiring intensive, reliable prestressing. For the prestressing operations, about 1,460 t DYWIDAG Strand Tendons will be used that are delivered by DSI Portugal just in time to the construction site.
The main contractor, CONDURIL, has been successfully cooperating with DSI Portugal for more than 10 years and is highly experienced in installing DYWIDAG Stressing Systems. Therefore, the entire post-tensioning work will be carried out by CONDURIL itself. The entire bridge is built using the free cantilever construction method. Up to 6 form travellers will be used at the same time. A total of 69,174 m3 of concrete and 7,600 t of structural steel will be needed for the construction of this viaduct.
The bridge is to open for traffic in summer 2006.