Wiesbauer deploys Liebherr LG 1750 for Stuttgart bridge replacement

Wiesbauer assembled its Liebherr LG 1750 on the banks of the River Neckar to remove the wooden bridge which was installed in 1977.

The Liebherr LG 1750 provided sufficient hoisting capacity for this job with its 84m main boom and total ballast of 530t. The larger section of the Neckar bridge, measuring 72m in length, was removed.

After taking material samples and examining the design documents, the project planners expected the bridge to have a total weight of 110t. However, it quickly became clear when the roofed wooden bridge was hoisted that it was significantly heavier than had been calculated.

It was not until the feet of the bridge came away from the abutments and river piers that the display in the crane cabin of the LG 1750 revealed the actual load: 142t.

The weight difference was the result of a large number of gusset plates and iron reinforcements which had been installed.

“However, this unexpected increase in the load case did not take the experts from Wiesbauer completely by surprise. Plenty of crane ballast had been transported to the site and the Liebherr 750t lattice boom crane had plenty of lifting capacity in reserve,” Liebherr said.

Ultimately a total of 530t of counterweights was placed on the turntable and in the derrick boom tray in the 18m radius.

The wooden construction was slowly swung over the River Neckar and placed on the bank for final demolition.

The pedestrian bridge over the River Neckar was built for the Federal Garden Show in 1977. When it was opened it was one of the longest roofed wooden bridges in the world. The eastern section of the structure is to be removed over the next few months.