Determining the scope of (structural) renovation of aging tunnels is a complicated task and modular renovation is becoming increasingly necessary. The COB Tunnel Programme aims at developing the knowledge necessary to renovate these tunnels in a modular fashion, to reduce hindrance as much as possible. Part of this program is the development of a Structural Health Analysis (SHA) for collecting data on the condition of the civil structure of tunnels, which will give tunnel owners insight in the need for research on structural parts of the tunnel, refurbishment and the risks for the tunnel performance in the future. As a lot of knowledge will be gathered and generated, structurally securing of this knowledge is also necessary. To meet this need, the tunnel program also started development of a knowledge management system. This paper describes the aims of the knowledge management system in relation to the overall tunnel program, as well as the tools and methods devised to gather all necessary information for tunnels constructed several decades ago, where not all required information is readily available in digital form, or even in paper archives. @en

The COB is The Netherlands Knowledge Centre for Underground Construction and Underground Space. Over sixty organisations, from government, industry and knowledge institutes, work together to learn and develop smart solutions regarding tunnels. This network has developed a long-term vision on tunnels in The Netherlands. As a result, nineteen tunnels and all stakeholders collaborate on eight research topics of our tunnel programme. We found common ground and the key issues are already being addressed in both practice and science. Topics include risks, construction failure, modular renovation, digital tunnel twin, virtual testing, virtual education and system safety. The way clients, science and industry work together within the COB network has been a major precondition to achieve these great results in such a short period of time.@en

In this paper we present issues related to the performance of immersed tube tunnels in the Netherlands. A range of issues are experienced for the ageing structures including long-term settlement at tunnel joints and consequent leakage. Because of the age of these structures some important aspects are often unknown thus creating uncertainty regarding remediation measures. Having discussed general issues the paper presents a case study of the Kil Tunnel which has experienced relatively large settlements over the past 40 years. In this case a lack of geotechnical engineering information for the soils below the tunnel was identified. A geophysical survey was undertaken and this provided ley insights into the ground conditions at the tunnel site.@en