Paderborn-based crane service provider Hofmann Kran-Vermietung & Co. KG Autokrane relied on the Terex Superlift 3800 lattice boom crawler crane in order to erect a 200-meter Nordex wind turbine close to Bickenbach, in the Hunsrück mountain range, on behalf of its client KS Regenerative Energie. To reach the required hub height of 164 meters, the Hofmann team equipped the crane with a full Boom Booster configuration, including a Flex Frame and Split Tray.
“We’d already used the Superlift 3800 to carry out several standard lifts for wind turbines with a hub height of up to 144 meters, but the project in Bickenbach was the first time we had to take a crack at a total wind turbine height of 227 meters” reports crane operator Christoph Bergmaier. An ideal task for the Boom Boosterhttp://www.terex.com/cranes/ru/aboutus/news/UCM03_115469.html, which Terex developed specifically for this type of lift. The Boom Booster system is a welded steel structure that is mounted directly on the crane and consists of up to seven twelve-meter-long sections. When equipped with this system, Superlift 3800 units can reach a maximum hook height of 174 meters and lift loads of up to 80 tonnes when using this configuration.
177-meter boom set up without assist crane
In order to erect the large wind turbine in the Hunsrück mountain range, the crane was equipped with a 165-meter main boom and a 12-meter LF jib. “That was the first time we ever used the complete Boom Booster system with all seven sections, which of course meant we were really excited to see how things would pan out. Not just when setting up the crane and with the Split Tray and Flex Frame options that we were using as well, but also during the actual work later on,” explains crane operator Christoph Bergmaier. And the reason was obvious, as the very idea behind these two Terex solutions is exactly the kind of thing crane operators want: The Superlift Split Tray is used when erecting the main boom. Once the main boom is set up, the counterweight that is no longer required can simply be uncoupled, after which the Superlift 3800 crane can move with only the Superlift counterweight that is still needed. After the crane is done with its work, the counterweight that was originally removed can be quickly put back in place in order to lower the main boom. This quick-coupling technology eliminated the work involved in rearranging counterweights for the Hofmann team, which reduced the setup time, eliminated the need for an assist crane, and made it possible to work with a smaller team. The Flex Frame unit also proved to be helpful when setting up the crane, as the team used it to increase the Superlift radius to 21 meters so that it would be possible to erect the boom, with its total length of 177 meters, without the need for an assist crane.
Before this, however, the team had to overcome a different challenge, namely, the relatively steep slope at the tough work site. “A boom with this kind of length needs to be kept at a perfectly horizontal position,” explains Bergmaier. Because of this, the technicians first had to set up a support platform of the same length in order to compensate for the slope.
Once all the preparation work was complete and the crane was set up, the team made the necessary arrangements so that the Superlift 3800 would have the required working configuration: The Superlift counterweight, which was only needed to erect the boom, was quickly removed without any need for the laborious rearrangement work that would have been required without the Split Tray option. This left only 25 tonnes of “remaining counterweight,” which was still more than enough to enable the crane to handle all the upcoming lifts. “On top of that, we used the Flex Frame to move the working counterweight up closer to the crane at a distance of 13 meters, which enabled us to comfortably maneuver with a minimal counterweight radius so that the tight space conditions at the work site wouldn’t get in the way,” explains Christoph Bergmaier.
All expectations met
From the crane operator’s perspective, there was one dominating question when it came to the lifts: How would the Superlift 3800 work with the Boom Booster installed? “With the same precision and smooth response that characterize the standard main boom – you can’t tell the difference at all,” says crane operator Christoph Bergmaier, praising the crane’s lifting capabilities when equipped with the Boom Booster system. He then adds: “Even with this type of demanding lift at a height of over 160 meters, the machine didn’t even bat an eyelash. Even when lifting heavy loads, you can’t hear any stress relieving as is typical for these types of cranes– I’m sure I could have picked up even more without a problem!” And his hunch is correct, as a look at the load table for the Superlift 3800 crawler crane confirms.
About Hofmann Kran-Vermietung GmbH & Co. KG
Hofmann Kran-Vermietung GmbH & Co. KG, which is headquartered in Paderborn, was founded in 1962 under the name of Walter Hofmann KG Autokran-Vermietung. Today, the company employs around 120 people and has a fleet with 400 machines, including a total of 41 mobile cranes with lifting capacities of 7 to 600 tonnes and 185 aerial work platforms. Hofmann Kran-Vermietung GmbH & Co. KG has a total of 14 branch offices in North Rhine-Westphalia,
The enviable reputation it enjoys as a professional and reliable business partner among wind turbine manufacturers and customers from the reinforced concrete construction, structural and civil engineering, prefabricated construction, large-scale industry, and petrochemical sectors extends far beyond Germany’s borders.