France - Port of Calais

For the expansion of the port of Calais, a breakwater of about 3km was built by the Bouygues-Jan de Nul combination.

In close collaboration with Jan de Nul and other specialists, the design of the breakwater core was modified: instead of traditional quarry run, Bontrup's Widegrade® product was used because of its logistical advantages. The stability of Widegrade® was extensively investigated by Bontrup in physical scale model tests. The results showed that, also during construction, the structure is stable under the severe wave conditions on the open sea.

A ship-to-ship delivery method was selected, where the material was loaded from self-unloading bulk carriers directly into Jan de Nul's floating equipment and subsequently placed into the breakwater.

In addition to the delivery of approximately 1 million tons of WideGrade®, armour rock up to a grading of 3/6T was supplied as well, also via transshipment.