02/13/2017 Liebherr LTM 1090-4.1 mobile crane installs sluice gate in dam wall

  • 90-tonne crane from Ley on dam wall of the Aggertal dam
  • Gate reinstalled at a water depth of 20 metres after refurbishment
  • Narrow area means only half the crane outriggers can be used

One year after the removal and refurbishment of a submersible sluice gate at the Aggertal dam, 50 kilometres to the east of Cologne, the sluice gate required to control the water level was reinstalled underwater. The job was carried out by a Liebherr LTM 1090-4.1 mobile crane operated by Gummersbach crane contractor Ley.

Idyllic backdrop: the LTM 1090-4.1 installing a sluice gate

Idyllic backdrop: the LTM 1090-4.1 installing a sluice gate

The sluice gate, which had previously been removed and completely refurbished, had to be reinstalled at a water depth of 20 metres, at around half the height of this massive dam in the “Oberbergische Land”. For the LTM 1090-4.1 the job meant a gross load of around 11 tonnes which had to be handled with just half the crane outriggers due to the narrow area available. The road along the top of the dam wall was closed to traffic for the duration of the underwater installation work, which was monitored by divers. With a clearance of just two millimetres between the sluice gate and the vertical rails mounted on the dam wall, the installation of the gate demanded absolute precision from the crane and the driver. However, the component measuring over four metres was positioned on the dam wall without any problems and let down into the water.

Constricted conditions on the top of the Aggertal dam wall in Oberbergisches Land.

Constricted conditions on the top of the Aggertal dam wall in Oberbergisches Land.

Ley based in Gummersbach has cranes, forklift trucks and work platforms in its portfolio. The fleet comprises around one dozen mobile cranes, the largest being the LTM 1500-8.1 and almost all of which bear the Liebherr brand. An order for an LTM 1450-8.1, which is due to be launched this year, has already been placed in Ehingen. One of the first of these modern 450-tonne cranes will be supplied to Ley.