The successful tandem lift carried out by two Liebherr LTM 1230-5.1 mobile cranes marked the successful completion of a meticulously planned feat of engineering. Given the tight timeframe whilst the motorway was closed, the lift was simulated in advance under realistic conditions on the premises of Hodel SHLK AG: pre-assembly of the three-part pipe bridge, followed by lifting and setting it down on simulated supports using the original spacing parameters. The pipe bridge was then dismantled into its individual components for transport.
A total of four night-time operations were required to install the massive utility bridge on the motorway. Before the final tandem lift of the total load could take place, the pipe bridge was reassembled on an adjacent existing bridge over two night shifts and prepared for installation. In addition to the LTM 1230-5.1, another Hodel mobile crane, an LTM 1100-5.2, was deployed. Whilst this crane assisted with the precise positioning of the components alongside the bridge, the LTM 1230-5.1, positioned on the motorway, took on the main load.
The installation teams faced additional challenges due to two high-voltage power lines running on either side of the motorway in the immediate vicinity of the construction site. As this vital power line – which supplies the Swiss rail network and serves as a key link to Ticino and northern Italy – could only be partially de-energised, so-called pennant ropes were installed beneath the lines. These marked the maximum permissible working height for cranes and loads in that area, thereby ensuring the safe execution of the lifting operations.
Diorama as a planning tool
These high-voltage power lines were even incorporated into a diorama created in advance with great meticulousness. The detailed construction site model on a scale of 1:50 realistically depicted all relevant objects. In addition to the power lines, the cranes and construction machinery deployed, the pipe bridge and the motorway lanes were also precisely replicated. The vivid model proved to be a key planning tool for coordination between the numerous companies and authorities involved in the project.
Jörg Hodel’s intensive preparation and precise planning paid off in every respect: during the crucial night-time operation, everything went smoothly, and the strict time constraints imposed by the full closure were adhered to exactly. At the start of the closure, the teams from all participating partners, as well as the mobile cranes, had taken up their positions at the access roads to the construction site. Everyone involved knew their role; the procedures were clearly defined and coordinated. After a good hour, a fully ballasted and securely supported LTM 1230-5.1 ready for operation stood on each carriageway. The attachment of the load to the pre-defined points, the lifting of the pipe bridge and its placement on the supports with millimetre precision all went as smoothly and precisely as clockwork. The cranes had already left the construction site before the morning rush hour began.
Hodel SHLK AG, based in Hochdorf, north of Lucerne, specialises in pipe and plant construction. The owner-managed company also offers the construction of heating and energy centres, as well as services in the fields of steel construction, transport, crane operations, civil engineering and surveying.
