Complex cable construction implemented with efficiency – PFEIFER builds lightweight semicircular bridge in Salzburger Land
Due to their longstanding experience in bridge construction, PFEIFER Cable Structures was the first choice for the job contracted by the steel construction company Urbas Maschinenfabrik. Already during the planning of the bridge, the specialists in lightweight cable structures consulted the company and supported the cost-effective and hitch-free construction of the bridge, beginning with the sketch up to the commissioning of the bridge. The curved form of the bridge and the, therefore, necessary calculation and planning presented the biggest challenge during the project. Each and every cable is unique ¬– from the guy wire and the suspender cable to the support cable, each rope has its own fixed, precalculated position within the bridge construction. All aspects, such as load, the curvature of the cables and of course their assembly, must be taken into consideration.
Pre-made and manufactured for the individual requirements
Another advantage that PFEIFER products offer is the European accreditation: No matter where the cables are used in Europe, no further inspection by the local authority is required. This saves time and paperwork for building contractors and developers. To ensure a smooth process during assembly on-site, it is essential that the steel cables are prepared for reshaping at the Memminger factory and already brought into the first form. All used cables were made by the experts at PFEIFER prior assembly and manufactured to fit the specific requirements of the bridge in Salzburger Land. The cables had undergone a thorough quality inspection before they were delivered to the construction site: To ensure the cables would withstand heavy loads on a long-term basis, the structures were inspected with a testing device before leaving the production hall. The entire bridge construction is carried by a single 110-meter long support cable secured with a pylon. Thanks to the robust cable support structure, no additional piers are necessary, which would disturb the floating impression of the bridge – the lightweight construction carries the bridge deck completely. Once the cables arrived at the construction site, everything only needed to be connected thanks to the extensive preparation beforehand. Therefore all of the suspender cables were attached to the support cable with rope clamps. The suspender cables are required to create the connection between the supporting cable and bridge deck. In addition to the delivery of the cables and clamps, the experts at PFEIFER also took care of the assembly and developed an individual concept designed for the location. The project depended on the precise and quick execution of all tasks after all.
Efficient and trouble-free – the assembly
The primary challenge during construction was the very tight schedule. Up until its completion, the bridge deck was very sensitive. Every step of the assembly had to be done in the shortest amount of time to prevent any damage. First, the three parts of the circular ring carrier were placed on top of the steel cone and welded by the structural steelwork engineering company Urbas. Following this, the cable professionals from PFEIFER began to attach the cables: The pylon was stabilized with the help of the guy wire and an assembly cable before the support cable together with all of the suspender cables could be pulled up from one end of the pylon and assembled. The other end of the support cable was attached to the counter bearing, producing the necessary tension and stability by diverting all of the forces from the bridge overhang. The suspender cables hung first loosely on the bridge deck and were then gradually connected to the bridge. With the bridge now activated, the entire load of the bridge was passed over to the cables, and the steel cones could be detached. The work of the cable specialists was so exact that no re-stressing or readjusting of the cables were necessary and the bridge could be commissioned after four weeks following its assembly.