Hollow Cubes

Based on the experiences on Test Structure Baltrum Hollow Cubes disposing of plane base areas (Tube cubes) to be used as single-layer revetments had been modified in using recesses at the vertical edges
  • providing auxiliary devices for picking up 4 or 9 elements simultaneously and
  • allowing the phreatic pressure to reduce.

Model investigations - sponsored by BMBF (FKZ 1701098) - carried out at Fluid Dynamics Laboratory of Bielefeld University of Applied Sciences. Main purpose: Stability of hollow revetments of slopes inclined 1:1.5, 1:2.0 und 1:2.5.
Results with reference to the selected shape assigned by porosity of 36%:
  • Up to the slope inclined 1:2 hydraulic efficiency is nearly as good as that of Test Structure Baltrum (1:3).
  • No problems with regard to the stability of any slope.

Energy Density Spectrum
Hydraulic Efficiency compared to that of a plane sloping structure is documented by:
  • significantly less wave runup
  • significantly less amount of wave energy seaward of the sloping structure and
  • significant change of breaker type.