In the week of March 31, 2025, Rijkswaterstaat announced that a type of steel potentially susceptible to hydrogen embrittlement was used in 13 bridges and viaducts. This could lead to cracks and weaken the reinforcements strengthening function, compromising the structure.
The investigation was prompted by the collapse of the Carolabrug in Dresden (Germany) on September 11, 2024. One of the bridges where this type of steel may have been used is the approach viaduct to the Algerabrug. The approach viaducts are managed by the municipality. The Algerabrug, including the approach viaducts, is safe to use.
In the week of March 31, we discussed the results known so far with the involved municipalities of Krimpen aan den IJssel, Krimpenerwaard, and Capelle aan den IJssel. Agreements have been made on how to proceed together with the next steps.
Algerabrug is safe
Research by Rijkswaterstaat shows that there is currently no acute safety risk. A second opinion, conducted by TNO, TU Delft, and TU Eindhoven, confirms this conclusion. The steel processing method involved in the German Carolabrug is different.
Currently, no management measures are needed, such as installing support structures or restricting traffic. Reinforcement steel has been used in the construction of the so-called approach viaduct on the Krimpen aan den IJssel side. It does not concern the bridges structure itself, which is also entirely made of steel and will be maintained as planned in the summer of 2026.
Next Steps
The research provides 5 recommendations to get and maintain a clear view of the specific situation at the Algerabrug approach viaduct and any safety risks: inspection, monitoring, determining steel type, additional numerical assessment, and strengthening the bridge if necessary. We will work on this in the coming period. We will collaborate with the municipality of Krimpen aan den IJssel.
Algerabrug Maintenance 2026 Continues
The Algerabrug, located between Krimpen aan den IJssel and Capelle aan den IJssel, will be closed for several weeks in August 2026 for planned maintenance on the bridge deck. During the closure, we will replace the wooden beams and steel longitudinal beams of the deck and conserve the entire steel structure.
Asphalting work will also be carried out. These works are unrelated to the hydrogen embrittlement issue of the concrete approach viaduct. The maintenance in the summer of 2026 is necessary to keep the bridge (and lock) available. Preparations for this continue.