The clients were the construction company Leonhard Weiss GmbH & Co. KG and the heavy haulage and crane company Dietmar Floßdorf GmbH & Co. KG. The performance and precision of two Liebherr heavy-duty cranes from Richter Kran und Schwerlast GmbH were relied upon for the installation of the heavy bridge elements and steel structures.
Tandem lift of 105 tonnes at a reach of up to 38 metres
The focus of the operation was the lifting of a bridge segment with a total weight of 105 tonnes, which was moved jointly by both LTM 1750‑9.1 cranes in a tandem lift. The maximum outreach was 38 metres. Both cranes were configured with a 28-metre luffing jib and 204 tonnes of counterweight each, thus providing the necessary reserves for the precise lift.
Due to the confined space directly on the banks of the River Ahr, the cranes had to be set up close together. An additional technical feature was the use of a triangular spreader, which ensured that the load was distributed evenly between both cranes.
Lift in the early hours of the morning – for good reason
The crucial main lift was deliberately carried out at 4 am. At this time of day, temperatures were at their lowest, thereby minimising the thermal expansion of the steel component. At higher temperatures, there would have been a risk that the bridge girder would not have fitted precisely into the designated abutments due to expansion.
“The team and everyone involved did an excellent job. The operation went ahead without any complications or incidents – exactly as planned,” says Thorsten Mahlberg, project manager at Dietmar Floßdorf GmbH & Co. KG.
Precision work in a very confined space
The logistical and technical challenges began right from the set-up stage: first, the first LTM 1750‑9.1 was positioned and erected. This crane then assisted with the set-up of the second unit. During the tandem lift, the utmost concentration was required – particularly to ensure the load on the triangular crossbeam remained precisely and evenly distributed at all times.
“A specialised operation in very confined spaces. A major challenge – but in the end, everything went to plan,” reports Manuel Bergmann, crane operator of the blue LTM 1750‑9.1. Michael Schmieder, operator of the white LTM 1750‑9.1, also emphasises the precision required: “We had to work with great concentration and precision to keep the load on the triangular crossbeam and on both cranes constant. I’m very relieved that everything went according to plan.”
The successful tandem lift impressively demonstrates how high-performance crane technology, careful planning and an experienced team enable precise and safe solutions even under the most difficult conditions. Once the main assembly was complete, one of the LTM 1750‑9.1s was dismantled, whilst the second crane was moved to the opposite bank to carry out further remaining work there.
