The Minister of Transport, Public Works and Water Management instructed the Directorate-General for Public Works and Water Management (Rijkswaterstaat) to put up safety screens on bridges over motorways to stop vandals from throwing down stones and other heavy objects on to passing vehicles.

Plans were made for three high-risk bridges across the A2 motorway at Maarssen (Haarrijn slip road), Breukelen (Ter Aaseweg) and Abcoude. The safety screens on the Maarssen and Abcoude bridges are of a similar kind. A special feature of the Breukelen bridge is its horizontal radius. The safety screen attempts to stay in a straight line under the force of the cable, but the radius makes it bend with the bridge. This exerts additional pressure on the structure from the surface around the cable support points.

The main supporting structure of the safety screen consists of curved stainless steel columns with a diameter of 219.1 mm. The upper cable with a diameter of 26 mm rests unclamped on the columns and consists of a single section running from side to side. The lower cable has a diameter of 10 mm and is supported at each baluster. The safety net is tensioned between the upper and lower cables and has a mesh size of 50 x 87 mm. Like the columns, all structural members are made of stainless steel. This material was chosen to meet the life cycle requirement of 50 years and the specified completely maintenance-free design. The screen comes into contact with road salt. As the screen is mounted above the A2, it was logical to refrain from using a paint system.

Iv-Consult has entered the structure in the Tekla 3D drawing application. The workshop drawings were also produced with Tekla.

Structural Engineer: Ing. Peter de Bliek (Project Manager Construction at Iv-Bouw)

Photo’s: Ysbrand Broekhoven (Iv-Groep)

Architect:  Ir. Aletta van Aalst (Aletta van Aalst & Partners b.v.)