The largest floating lemniscate crane in the Netherlands has an adorable name: the Hippo. The crane owes this name to its shape. The floating slewing crane, in use at OBA Bulk Terminal in Amsterdam, has a lifting capacity of no less than 50 tons. Vicoma designed structural improvements to stop cracks in the construction.
Project: cracks observed on bottom of Hippo’s barrel
The crane in the Western Port Area is used for bulk transshipment. Cracks were found in the wall of the ‘ton’ (the vertical circular red part) at the bottom, just above the turntable. The stiffening strips applied in the past proved to be sub-optimal.
Vicoma’s role: using FEM analysis to find the solution
Vicoma engineers used FEM analysis to find the optimal shape for the stiffening strips. The crack analysis resulted in new stiffener strips with a different shape, which means the maximum stresses occurring are lower and will occur at a different location in the barrel wall.
Result: peak stress halved with new stiffening strips
In the meantime, the existing cracks have been repaired and the previously applied stiffening strips have been removed In the new situation, the peak stress in the structure has been halved and the maximum stresses occur at a different location in the wall of the barrel.