Höhns-Bau was already using a Potain MDT 218 on the HafenCity jobsite but, according to managing partner and engineer Jens Höhns, the acceleration of the construction schedule meant it required a second crane to be erected on site.
“There were two options available to us,” Höhns said. “Either we could erect a larger crane, farther away from the project that could swing over the construction.
“Or we could erect a topless crane with a shorter jib that would swing underneath the crane that was already erected. We chose the second option.”
Manitowoc’s Potain topless tower cranes do not feature a cathead above the jib, allowing them to operate in close proximity to other cranes on construction sites.
The first Potain crane on site, the 8t capacity MDT 218 A J8, was erected with a 40m jib giving it a jib-end lift capacity of 4.6t. The crane was mounted on a 4.5 x 4.5m base with 1.6 x 1.6m mast sections. Height under hook for the crane is 55.7m.
The second crane, the MDT 268 J12, was assembled farther away and above base level. The MDT 268 is able to rotate under the MDT 218 as it is installed with a 52.4m height under hook, and its base is 2.5m lower on the job than the MDT 218. As the distance between the mast of the two cranes is 30m, the MDT 268 is working with a 25m jib. It has a 12t maximum capacity, and it can lift 9.4t at jib-end.
Höhns said the two cranes worked well together. “The components we’re lifting weigh up to 9t, so with the combined lift ability of 20t, there is plenty of flexibility.
“They work really efficiently together even though they are operating in a tight space.”
