German crane contractors Sommer-Kranverleih from Bremen and Autokrane-Spallek from Ibbenbüren have collaborated on a bridge dismantling job, each using a Liebherr LTM 1300-6.2 mobile crane to complete the work.
The contractors had a two-night deadline in which to complete the work, says Liebherr. The job involved cutting two 80-tonne reinforced steel supports in half using wall sawing equipment. The bridge ran over a railway track and the Liebherr mobile cranes were positioned on either side of the railway track, around eight metres below the bridge. The cranes' attachment equipment was secured to each half of the 80 tonne concrete supports before the supports were then sawn through in the centre and at the abutments. It took around four hours for the diamond-tipped wall saw to cut through the concrete supports, which measured around two metres in height.
Liebherr says the crane drivers had to work quickly and accurately because they had to ensure that the freely suspended sections of the support, measuring around 15 metres in length, did not tilt. The two 300-tonne cranes managed the load of around 42 tonnes with a radius of around 15 metres.
Below-zero temperatures and thick fog made work on the site difficult and uncomfortable, Liebherr tells us. During the first night, the team only managed to remove one of the supports rather than the two that they had hoped for. On the following night, however, the two remaining concrete supports had been removed by the morning and rail traffic could be restarted as planned.
"Our collaboration went very well," commented the managing director of Sommer-Kranverleih, Jörg Sommer, after the work had been completed. Sommer, based in Bremen, and Spallek, which operates from Ibbenbüren, are long term Liebherr partners. Their fleets each comprise around a dozen cranes, all of which have been supplied by the Liebherr Plant in Ehingen.