08/02/2022 Alpine crane job on constricted site
- Liebherr LR 11000 crawler crane replaces railway bridges in the Swiss Alps
- Increased central ballast means no need for a derrick boom or suspended ballast
- First bridge replacement completed after a few hours
A Liebherr LR
Michael Egger, Managing Director of Emil Egger AG, based in St. Gallen, transported his 1,000-tonne crawler crane to the south-east of Switzerland to replace three railway bridges, all of which were around 100 years old. Work on the first bridge structure was particularly challenging – due to the limited space available for the crane on a metalled embankment facing the adjacent road, it was not possible to use the derrick boom with its suspended ballast.
"To ensure we have sufficient stability for lifting the new, significantly heavier railway bridge, we had to maximise the central ballast on the crane to compensate for the lack of suspended ballast," explains Egger, who planned the operation with his colleague, Andreas Schönenberger. Prior to carrying out the work, he had discussed the load case in this unusual configuration with the specialists at Liebherr in Ehingen: "The LR 11000 is equipped with 90 tonnes of central ballast as standard. We have therefore packed 130 tonnes into the crane for this operation after Liebherr gave us the OK to do so." The slewing platform ballast was loaded with the maximum counterweight of 250 tonnes.
"Up to the limit of the load chart"
Before the new steel structure, which is around 35 metres long and was assembled on site from several segments, could be placed in position, the old bridge structure first had to be removed. The 65-tonne truss construction was quickly lifted off the abutments and set down on the edge of the mountain river, actually next to LR 11000. It was then repositioned later for removal. Afterwards, the crawler crane was able to lift the new bridge from the special transporter on the road and position it above the river using a radius of around 22 metres. "With this radius and a gross load case of 205 tonnes, we are almost at the limit of the load chart for the crane in this particular configuration," says Egger.
The LR 11000 was erected and dismantled by a Liebherr LTM 1250-6.1 mobile crane belonging to Sabesa SA, a crane and haulage contractor based in Ticino. Andrea Saccomandi, Managing Director of Sabesa, which was actually the main contractor for the replacement of the three railway bridges, was personally on site for the crane job. Based on the northern shore of Lake Maggiore, the company's portfolio includes crane work, transport services and platform hire, and its fleet includes around a dozen Liebherr mobile, compact and mobile construction cranes.