Bridge challenge for Senn’s new Liebherr

Swiss crane contractor Senn used its new Liebherr LTM 1160-5.2 mobile crane to replace a 100-year-old bridge in Aarwangen in the Canton of Bern, Switzerland.

The LTM 1160-5.2 worked with a Liebherr LTM 1130-5.1. The job was carried out over eight nights. Due to the location of the bridge, the cranes worked on a narrow, parallel road bridge. Both cranes had the Liebherr Variobase system, which enabled the cranes to be positioned on the side of the road and have supports variably extended on the side facing away from the load, a spokesperson said. Load distributor plates specially built for this job were used to ensure ideal distribution of the support pressure on the bridge's structure.

Dismantling the old truss construction took four nights. The new 100-metre trough bridge with closed walls was then installed over a period lasting a further four nights. On all nights the river crossing was closed.

The new bridge segments were delivered from the production site of Senn in Oftringen on a low loader.

Due to the lack of space, the cranes were driven onto the bridge with the boom fully raised and ballasted. To install the sections, the two cranes were positioned at either end of the 25 metre bridge sections. The 50 tonne sections were then lifted over the river and lowered onto the piers, auxiliary piers and abutments.

Jörg Senn, Senn managing director, said, “The LTM 1160-5.2 is without doubt the most modern crane in its class on the market. The main factors behind the decision included the new Tier 4 engine technology, the technical feature involving the VarioBase support system and LICCON 2, its modern control software. The adjustable ballast radius which allows the operator to vary between two positions is another fantastic feature.”