Old becomes new: Prangl replaced an ÖBB railway bridge
The railway bridge, which is more than 100 years old, had reached the end of its service life and needed to be replaced with the help of the lifting experts from Prangl. 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 for everyone involved.
No space but an effective concept
The site was located in a gorge with only rock walls on the left and right. There is only the Salzach river, a road and the railway line. In the months leading up to the lifting operation, the new bridge was assembled approximately 300 metres away. The new enclosed framework, which rises more than a half-dozen metres and spans 70 metres, was built by the roadside. Due to the lack of space, the supporting structure had to be prefabricated next to the road. Some of the road had to be closed at short notice.
Three self-propelled heavy-duty trailers synchronised
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. Due to the restricted space and the framework's length spanning 70 metres, this first phase immediately demanded the utmost concentration of all participants.
Difficult setup of the 650-ton crawler crane
In order to set up the 650 ton crawler crane provided for lifting, the Salzachstraße had to be completely closed in stages. 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.
Lifting work under time pressure
We were finally ready o go: 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 travel again unhindered in the morning, there was only a time slot of just under two hours available. All participants were under tremendous pressure. 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.
Highest concentration from the entire Prangl team
Despite difficult wind conditions, the new bridge was lifted with pinpoint precision. In order not to put the existing supporting structure of the adjacent second track at risk, both lifting operations (the old and new bridge) required the utmost concentration of the entire team, since the 70-metre-long structures were now 20 metres above the ground. Since the construction site was located directly above the water and the dangerous Salzach gorge begins right below it, a water rescue team was on standby all night below the construction site.
Successful completion impressed the customer
The Austrian Railway Services managers were very enthusiastic: "A construction site of this magnitude, situated in a gorge, 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. This requires a strong team and reliable partners.”