Belt conveyor above the highway

To transport more than 1 million cubic meters of sand

N.M. Heilig has designed and built a special belt conveyor over the highway as part of the renovation project of the 90-year-old ‘Afsluitdijk’, the dam that stretches 32 kilometers and protects the Netherlands against storms and flooding. The belt was designed to be transported, assembled and erected in a weekend and will transfer appr. 1.2 million cubic meters of sand during the course of the project.

Sand transportation above one of the most important highway of The Netherlands

In order to minimize the effects on both road and boat traffic, the enormous amount of sand needed for the reinforcement works is being transported above the highway from the IJsselmeer (lake) side. This is the first time that a system of this nature has been implemented on a large scale basis over a major highway in The Netherlands. This method of transportation for the sand has eliminated the requirement for an estimated 4,000 ship movements through the locks between Kornwerderzand and Den Oever, as well as many additional transport trucks on the A7 highway.

Part of the project is to protect against the waves from the side of the Waddenzee. This is done by placing Levvel Blocs on a bed of sand. These are concrete blocks that hook together and have a wave retardant effect. N.M. Heilig has developed a conveyor belt installation to transport the sand on which the Levvel Blocs are placed from one side of the Afsluitdijk to the other.

Another requirement was that the conveyor belt could be put into place within 45 minutes. And on top of that, the installation has to be able to move to different positions along the bridge, as Levvel Blocs are being placed along the entire 32 kilometer stretch of the Afsluitdijk.

Highest safety and quality standards

The belt is fitted with special low-profile galvanized steel hoods, an enclosed wooden floor and high side walls at the bottom of the bridge structure to eliminate the possibility of blowing or falling sand. The floor is also fitted with a rubber layer under the belt to easily remove any potential spillage.

The bulk handling system is designed to handle sand, gravel and clay. It is remotely controlled from the loading barge, with safety interfaces between the systems. Electrical sensors monitor various aspects of operation, such as tracking of the belt. Special lighting was installed to minimize the effects on the local wildlife. Our team of project managers and engineers really enjoyed this project with its unique requirements and challenges.