In order to not disrupt traffic, the WOLFF 355 B luffing crane with its 55m jib and the WOLFF 6031.8 clear trolley jib crane with its 32.5m jib were both set up on a weekend.
The planning of the complex assembly alone required several meetings between Wolffkran, the construction company Lupp, the mobile crane rental company and the local site supervision. "The construction site is surrounded by busy streets and narrow plots with high-rise buildings, making the crane installation itself a major technical and logistical project," said Thomas Odenbreit from sales Germany at Wolffkran.
The WOLFF 355 B is installed on a 6.2m x 6.2m WOLFF Cityportal, under which the traffic can flow whilst the construction work is in progress. Six service technicians and three mobile cranes were on site for its assembly.
A 160t mobile crane was used to assemble the portal, the first three tower sections and to position the central ballast. The ballasting was supported by a 30t mobile crane. At the same time, the tower top and the counterjib were unloaded and prepared for assembly.
The WOLFF 355 B was assembled to a tower height of 64m, while the WOLFF 6031.8 with a hook height of 61m was assembled shortly after the luffing crane.
"In the summer, the 6031.8 will be used to assemble a second WOLFF 355 B luffing crane in so far, that a mobile crane will only be needed for the tower sections and slewing part. The newly set up luffer will then in turn dismantle the WOLFF 6031.8. In both cases, mobile cranes for the assembly, and consequently also costs, were reduced for the customer," explained Odenbreit.
The two WOLFF 355 B luffing cranes will gradually grow with the building up to a final tower height of 184m. Their high lifting capacities of 8.5t (WOLFF 6031.8) and 14t (WOLFF 355 B) are necessary for lifting construction material and prefab elements. "The heavy steel beams – concrete girders for ceilings and walls – some of which weigh over twelve tons, will partially even need to be lifted by both luffers together by means of a so-called tandem lift," explains Odenbreit.
Due to the particular shape of the building with its outward shifting floors at mid-height, the cranes are installed around ten to twelve meters away from the building instead of the usual five to six meters.
Thanks to the Wolffkran tower system HT 23, only four tie-ins to the building are necessary, despite a final tower height of over 180m.
With the planned completion of the 45-storey "high-rise with a hip swing" in 2019, Frankfurt am Main is entitled to a new claim: It will have the only crossroads in Europe where there is a high-rise building at each of the four corners. One of them, the TaunusTurm, was also built with four WOLFF cranes, between 2011 and 2014.
Within the last year, Lupp has extended its fleet by three WOLFF 6031 clear and one 7534 clear, which was only launched at Bauma last year. Two of Lupp's own WOLFF cranes will shortly go up on the construction site of the so-called "T-Rex Towers" at the Senkenberganlage in Frankfurt.
