Tandem hoist: Liebherr crawler cranes in Manchester

The LR 1750 commences its service on the construction site six months before the tandem hoist. The 750-tonne crane erects the lower section of the bridge directly above the river and assembles the 90-metre long bridge arch on the bank. For this, the Weldex workers transport the massive steel structure in small segments to the construction site in the middle of the city.

The Scottish crane company Weldex dispatches its most powerful crawler crane to the site for installation of the bridge arch using a tandem hoist. In just four days, the assembly team erect the Liebherr LR 11350 with 72-metre main mast and 42-metre derrick boom.

The hoist involves a massive load application for the LR 11350 owing to the required radius of 51 metres. The 357-tonne gross load is only possible thanks to the extended guide frame optionally available on this crane. That increases the radius of the derrick ballast pallet from 25 to 30 metres. This configuration, referred to as SLDB2, enables the crane to handle an additional load case of almost 50 tonnes with a radius of around 50 metres.

To lift the massive bridge arch over the river, the crawler cranes have to move it around 30 metres in stages up to the bank. The manoeuvre is performed synchronously and is interrupted on several occasions so the cranes can be provided with more ballast. An LTR 1100 telescopic crawler crane stacks the derrick ballast of the LR 11350 up to the maximum of 600 tonnes.