November 11 - The first model of Liebherr's new LTM 1160-5.2 mobile crane has been delivered to Swiss crane contractor Senn and completed its first job lifting a bridge over the River Aare.

Working with an LTM 1130-5.1 model, the new mobile crane helped replace a 100-year-old railway bridge in Aarwangen, in the Swiss canton of Bern.

With the road only measuring 7 m wide, the two mobile cranes were erected on the side of the road ready for the tandem hoist. The cranes both feature Liebherr's VarioBase supporting system, which the manufacturer said allowed them to have supports variably extended on the side facing away from the load.

Therefore, explained Liebherr, on the side facing the bridge, there was enough space to extend the outrigger beams to their maximum length. Load distributor plates specially built for the job ensured that the support pressure was distributed on the bridge's structure, added Liebherr.

Firstly, the cranes worked together to dismantle the old bridge; before installing the new 100 m long bridge over the river. The total operation took eight nights to conclude, with the river crossing closed to traffic during each night.

Every night a component of the new railway bridge was delivered from Senn's production site in Oftringen by low loader trailer, and positioned on the road bridge. Liebherr explained that since there was no time of space available to set up the cranes on the bridge, they were driven onto the bridge with the boom fully raised and ballasted.

The two five-axle mobile cranes were then positioned at either end of the 25 m bridge sections. After attaching and lifting the load, the support pressures on the crane supports were checked again, before the steel section, weighing around 50 tonnes, was swung over the river and lowered onto piers, auxiliary piers and abutments.

Once all the sections had been lifted and lowered, the units were installed with the help of Senn's crane drivers and structural steel erectors.

"We completed both the production and the transport and installation work for the railway bridge ourselves in full," said Senn managing director Jörg Senn.