ABSTRACT
In the Netherlands, many existing immersed tunnels will be renovated in the next decades to remain in proper condition for their residual lifetime. Ongoing settlements could be a threat to the structural performance, as it results in concrete cracking and leakages. This affects the structural reliability of tunnels, and the availability of the road network. Therefore, this paper presents a methodology to assess the tunnel structural reliability and availability, and suggests an approach of optimising the structural performance regarding ongoing settlements. The methodology involves a parametric structural model that determines the tunnel reliability and availability using a Monte Carlo approach. For the Noordtunnel case, the research demonstrates that reliability decreases over time, and the critical segment joints are identified. However, the results contain significant uncertainty. Given these findings, the maintenance and renovation strategy could be optimised by installing advanced monitoring systems, strategically injecting leakages, and further developing drastic renovation solutions.
