On 10. August 2019, the Netherlands was startled by what could easily have been a national disaster. On that day, there was a strong wind and, quite unexpectedly, part of the roof structure of the AFAS Stadium in Alkmaar (The Netherlands) collapsed. Fortunately, nobody was in the stadium at the time, so there was only material damage. However, the question immediately arose as to how this could happen and what the risks were for visitors to other stadiums. An investigation eventually revealed that faulty welding joints were the main cause of the incident in Alkmaar. As a result, most Dutch stadiums were investigated further as a precaution. MME Group was called in for this purpose in, among others, the Car Jeans Stadium in The Hague.
The examination of the welds of these roof constructions presented two challenges. The construction is situated above the stands. Using scaffolding or elevated work platforms therefore wasn’t an option for inspecting all critical parts. In addition, the structural elements are for the most part coated. Removing the coating for inspection would have entailed high costs.
For both challenges MME Group was able to offer a fast, efficient and safe solution. MME Group has a large in-house team of Non-Destructive Inspectors who are certified to ISO 9712 and IRATA standards to inspect these types of steel structures at height and in hard-to-reach places using climbing techniques, also known as "Rope Access".
For the inspection of welded joints under the coating, use is made of te so-called eddy current (ET) inspection method. This form of magnetic inspection can reveal surface cracks and other imperfections in the weld and the base material next to the weld without the need to remove the coating.
The investigation into the safety of the Cars Jeans Stadium structure has confirmed that it meets the safety requirements even in winds exceeding force 8. The Municipal Council has therefore decided that the stadium ring and the pitch of The Hague's Cars Jeans Stadium will no longer be closed as a precautionary measure in the event of such weather conditions or forecasts.
By contracting MME Group to carry out periodic NDT inspections during the usage phase, managers and owners of stadiums and similar complexes such as concert halls will gain insight into the exact condition of the steel construction. In this way they can assess whether further action is required and, moreover, demonstrate that they take safety extremely seriously.