In Kostrzyn nad Odrą the construction of a new road bridge over the Warta River, located along National Road 31 is underway. The purpose of the project implemented by Warbud SA is not to increase the capacity of the traffic capacity of the road itself, but to clear the water route. A new structure will be built in place of the old bridge, it will be 300 meters long, with better load-bearing parameters and, above all, a higher structure, thanks to which icebreakers and large-size barges will be able to pass under it.
Temporary bridge is ready now
The implementation of the entire bridge project is a complex and multi-stage task. The first stage is the construction of a temporary bridge right next to the existing structure. Thanks to the temporary structure vehicular and pedestrian traffic will still be possible in the center of Kostrzyn throughout the entire construction period of the new bridge. This project phase has just been completed and the temporary bridge has successfully passed static and dynamic load tests. It is a military Bailey-type bridge. Once the vehicular and pedestrian traffic is transferred to the new, temporary bridge, the project will enter the next phase - in September this year demolition of the old building will begin.
Engineering and environmental challenges
The operation of building the bridge in Kostrzyn is extremely complicated not only because of the wide range of applications of complex construction methods such as incremental launching, overhanging, prestressing, advanced monitoring of structure displacements, but also due to the difficult logistics associated with the necessity to carry out part of the works from the river with the use of barges and pontoons (e.g. demolition of the supports of the existing bridge) and because of the execution of works while maintaining uninterrupted road traffic flow (vehicles and pedestrians) within the Construction Site boundaries.
A big challenge were restrictions resulting from environmental requirements applicable to the bridge construction site, which is located in a strictly protected natural area, in the immediate vicinity of the "Ujście Warty" National Park, and even partly within its borders. Environmental decisions determined the time and manner of carrying out a number of works, in particular those related to direct intervention in the riverbed, i.e. removing sheet piles or constructing supports. It was impossible to carry out those works in the period from March to August. In turn, the demolition of the existing bridge is possible only in the period from September to February. As part of the contract, Warbud has strengthened the river bank and the inland part of the Somera Island and the bottom of the Postomia River around it, and will place nesting boxes for birds on the island. These works, as intended by the National Park, will create favourable conditions for the settlement of the "Somera Island" (the only one within this Park) by bird species desired by naturalists.
Rafał Chrostowski, Contract Manager at Warbud SA, comments that “thanks to our presence in the VINCI Group, we are able to independently (as a Group) perform such complex and demanding bridge structures as extradosed bridges. These are architecturally interesting structures resembling cable-stayed bridges. In fact, these structures combine the idea of a suspended and prestressed beam structure. Freyssinet, with whom we cooperate, is one of the world leaders in the field of cable-stayed bridges, bridge equipment and technologically complex structures. Under this contract, that company is responsible for the suspension and prestressing of the bridge. In addition, it will provide specialized equipment for this facility - bearings and expansion joints. During the construction project in Kostrzyn we also cooperate with Eurovia Polska regarding the spreading of asphalt pavements on the access roads to the temporary bridge and for the target road system. Eurovia Polska supplied hydrotechnical aggregate for our construction site for development of the "Somera Islands" (compensation works carried out by Warbud SA in the "Ujście Warty" National Park).”