Type of bearing-systemThe next step involved determining the type of bearing system. The variants were systems with:
The Hartel Barrier arched girders have a curved wall at the front, thereby bringing the centre of gravity closer to the system-axis. This results in slender and compact end-posts and towers. The curvature is polygonal. For aesthetic reasons it was decided in favour of nine fields in the large gate and five in the small gate. Truss-braces are located in the corners of the polygons to ensure the necessary interaction between the retaining wall and the rear edge.
Hartel Barrier construction costs: about 90 million guilders.