Benelux tunnel now fire-resistant

The Benelux tunnel between Schiedam and Pernis is a very important connector for the Port of Rotterdam and Botlek industrial areas. And given that tunnel is part of a primary flood defense system, the structural and fire safety of the tunnel is a top priority. During inspection works by Rijkswaterstaat it turned out that the coating and heat-resistant covering of the tubular struts at the entrance and exit of the tunnel were due for an overhaul. Given that these steel transverse supports keep the tunnel walls from collapsing, action needed to be taken. The work site posed a challenge, however: working above moving traffic in the tunnel. How do you protect the health and safety of the workers while also ensuring ongoing traffic safety, with minimal disruption to traffic?

New solutions for fireproofing

We came up with an unconventional solution for fireproofing the tubular struts, in the form of special heat-resistant wraps. Though this technique is often used in industry, it was a first for infrastructure works. Together with our people from Bouman and the concrete specialists of Vogel, on our own initiative we conducted research and carried out fire resistance testing in advance. The results were more than enough to convince Rijkswaterstaat. Around the strut covering we installed aluminum plates, which we had rolled exactly to size. Not only does this casing give the structure additional protection against weather influences: this finishing touch looks very attractive too. Though the question still remained: how are we going to safely apply the fireproofing, coating and aluminum cladding above moving traffic?

Custom-made suspended platform

Two concrete edges run one above the other on either side of the tunnel. Originally the plan was to have the platforms ride over these, however, the lower edge was not strong enough to support these. Together with Rijkswaterstaat, we investigated various possible solutions, finally opting for one involving a movable structure resting on the top concrete edge with a work platform suspended from this structure. Mourik Techniek built the entire system, completely made to order for this project. We repositioned the entire structure every two to three weeks – the upper structure with a crane and the work platform leaning on a trailer on which a sea container was mounted. We did this a total of 37 times in the course of the rehabilitation works, always at night to keep traffic disruption to a minimum. Working above moving traffic has consequences for road safety and traffic control, but certainly also for the health and safety of the workers. And so we took additional measures – on top of the safety standards we always apply – in the form of project-specific protocols and checklists to use each time the structure was repositioned. We also took more hands-on safety measures, like providing those working from the suspended platform with an emergency button.

The way we approached this rehabilitation project was classic Mourik: taking a proactive approach to come up with solutions that work in practice, and this while keeping an eye on the safety of the people working and the traffic passing through the tunnel. Our versatility truly came into its own in the Benelux tunnel. Mourik Infra, as the main contractor, supervised the design and execution, including all traffic measures (with colleagues from Traffic & More). The suspended platforms were built by Mourik Techniek and by our people in Echt. The specialists from Mourik subsidiaries Vogel and Bouman carried out the rehabilitation works. We can do it all and we know how to connect all the disciplines. The result? Fire safety in the Benelux tunnel is guaranteed for the next 25 years too.