Constrained spaces often make indoor projects a tricky proposition – especially when unwieldy loads need to be lifted. And this was exactly the case for the Merkel Autokrane GmbH job in January inside a production facility for precast concrete elements run by FTO Fertigteilwerk Obermain. In order to install a noise barrier with large concrete panels, Merkel decided to use the new Demag® AC 45 City, which is a perfect match for precisely this type of job.
“What we had to do for this project was lift the concrete panels, each of which weighed either three or six tonnes, exactly in place between support columns inside the narrow shop floor so that assembly technicians could then fasten them in place there,” explains Merkel Autokrane GmbH customer service representative Karl-Heinz Göring. The goal was to separate two sections of the shop floor from each other in order to reduce the noise levels in both of them.
A lift with obstacles
In addition to the already tight space inside the building, the lifts were made even harder by the fact that a crane runway was also in the way – the first panels had to be placed underneath the runway, while the last series had to be positioned above it. “To do this, we had to extend the boom until just underneath the ceiling. However, that wouldn’t have worked with a hook, so we instead worked with the runner and telescoped under load. And in certain cases, it really came down to the last few centimeters,” explains crane operator Oliver Lieb, who during the lift also had to look out for a large glass pane that he had to make sure not to get too close to.
The most particular challenge within this context was positioning one of the topmost panels, which pretty much had to be threaded in directly behind a crane runway girder with extreme precision. “Since there wasn’t enough space to set down the panel directly, we had to set it down on makeshift wooden supports, rig it again, lift it again, and then remove the supports to be able to set it down where we wanted,” Karl-Heinz Göring explains the complicated procedure. All in all, this proved that the AC 45 City was the perfect machine for the job.
Asymmetrically positioned outriggers
“The outriggers were perfect as well,” reports Oliver Lieb, who was always able to work with fully extended outriggers on the load side, but not on the other side, all depending on what the space conditions inside the building allowed for. Since the AC 45 City is equipped with the Flex Base, Lieb was able to take advantage of every single centimeter. This made it possible to carry out all the lifts smoothly and efficiently. The crane operator was accordingly very happy with the crane: “I’d already worked with its predecessor, the AC 40 City, and that was already in a category all of its own, but the AC 45 City is even better, and in every single aspect! To put it simply, I couldn’t have wished for a better crane for this job.”