Replacement of steel cables on the Zuidhorn cable-stayed bridge: swift action, safe completion
Replacement necessary after inspection
A movable bridge must continue to operate safely and reliably. Especially when inspections show that critical components are due for replacement. At the table bridge in Zuidhorn, an inspection carried out according to ISO 4309 at the end of 2025 showed that the existing steel wire ropes had reached the discard criteria. For Rijkswaterstaat and Mennens, the conclusion was clear: replacement was necessary, and as quickly as possible.
The table bridge moves vertically by means of cylinders. In addition, 16 balance ropes with a diameter of 52 millimetres ensure smooth, controlled and stable movement of the bridge deck. Precisely because these ropes are so important to the operation of the bridge, replacing them requires a careful approach: inspecting, assessing, intervening in time and testing demonstrably.
Bridge safely taken out of operation
In consultation with Rijkswaterstaat, it was decided to take the bridge out of operation as a precaution. To prevent disruption to shipping, the bridge was placed in its highest position. This kept the waterway available, while work towards replacement could continue in a controlled manner.
For road traffic, this caused temporary disruption, but from a safety perspective it was the right decision. Continuing to operate with ropes that have reached the discard criteria is simply not an option. In situations like these, safety, reliability and careful decision-making come first.
New ropes produced and extensively tested
Once the decision had been made, action was taken immediately. In consultation with Rijkswaterstaat, Mennens urgently ordered new steel wire ropes and sockets. Thanks to close coordination with suppliers and manufacturers, all materials were delivered within eight weeks. When a bridge is out of operation, every week counts. Not only for planning, but also for accessibility and social impact.
Before the ropes were sent to Zuidhorn, they were extensively processed and tested. The end connections were socketed, and the ropes were prestretched so they were exactly the right length and would behave consistently during operation.
In addition, both left-hand and right-hand lay ropes were examined. This included wire tests, torsion tests, zinc coating weight tests and breaking tests on complete ropes. This demonstrated that the rope set met Rijkswaterstaat’s project requirements and was ready for many years of safe use.
On-site execution in close cooperation
The on-site work took place in week 9. Mennens worked closely with Wagenborg for lifting operations and transport, Gjaltema for site setup and scaffolding, and Rijkswaterstaat for coordination and safety.
That cooperation was essential in combining speed with safety. In projects like this, every link has to be right: from preparation and transport to lifting work, installation and inspection. By coordinating the work properly, the bridge could be brought back towards operation as quickly as possible.
Trial operation successfully completed
On Friday in week 9, the bridge underwent a trial run. After successful completion of the trial operation, the table bridge was handed back to Rijkswaterstaat. This means the bridge is once again safe to use and can continue to perform reliably, remain available and operate safely for years to come. At the same time, the road traffic closure could be lifted.
For Mennens, this project clearly shows what matters in critical infrastructure: identifying issues in time, organising quickly and only handing over once everything has been demonstrably verified.
Prevent downtime: plan replacement before it becomes critical
Do you want to be sure your bridge or lock installation continues to operate safely, and do you want to replace components on time based on inspection data? Contact Mennens via the contact form or the button below. Together, we will look at inspection, replacement, testing requirements and an execution plan that fits your planning and safety framework.
