Railway bridge replaced within 2 hours
The railway bridge, which is more than 100 years old, had reached the end of its service life and needed to be replaced. In addition to the steel framework’s dimensions (70 metres long, 7 metres wide, 8 metres high and 350 tonnes), the confined spatial conditions proved to be a particular challenge. The site was located in a ravine of the Salzach river. Since the construction site was located directly above the water, a water rescue team was on standby all night.
In the months leading up to the lifting operation, the new bridge was assembled approximately 300 metres away. The Prangl team’s first task was to lift out the old bridge framework, which weighed a total 380 tonnes, load it onto three synchronised heavy-duty modules and drive it to the intermediate storage location by remote control. At the same time, the new bridge had to be moved around 300 metres to the lifting site before being transported. This was also carried out with the self-propelled heavy-duty units.
The Salzachstraße had to be closed temporarily to allow the set up of the 650 ton crawler crane. A total of 40 trucks were used to transport all components of the large crane, which was then assembled in four days under difficult conditions. When fully assembled, the giant yellow crane including the load weighed 900 tonnes.
The actual lifting work could not be started until shortly after the last train passed the track at 2:00 a.m. In order to ensure that the first scheduled train could start again in the morning, there was a time slot of just under two hours. The crane picked up the framework directly from the self-propelled heavy-duty modules. Due to the distance, the crawler crane had to change its position once and travel around 20 metres under full load. Despite difficult wind conditions, the new bridge was lifted with pinpoint precision.
The ÖBB managers were very enthusiastic: “A construction site of this magnitude, situated in a ravine, with the Salzach river and its fast-moving current along with a busy country road, poses a major challenge for everyone involved in implementing the project. From the planning stage through to the lifting operation itself, every move has to be right.”