Structural health monitoring in strategies for life-cycle management of dikes: a case study in the north of the Netherlands

In recent years there has been an increasing focus on life-cycle and asset management as a means of managing systems of ageing infrastructure. To accurately assess performance, structural health monitoring can be an important means. In this paper a tool is presented which assesses the costs and benefits of structural health monitoring in life-cycle management strategies for dikes. The tool is based on and applied to the Ommelanderzeedijk, an old sea dike in the north of the Netherlands that didn't pass its last safety assessment. Waterschap Noorderzijlvest has applied several monitoring techniques over the past years, such as piezometric head monitoring and temperature measurements as well as a failure test. These experiments have provided a variety of valuable information, which has led to a more effective design for the upcoming reinforcement. This case focuses on assessing the benefits of monitoring of the phreatic level in the dike body. With the developed tool, various strategies for monitoring can be compared based on their Net Present Value. Although in the actual case the benefits of monitoring were enormous, it is also shows that this can vary greatly depending on the case and that the amount of risk one needs to take in order to obtain information is pivotal in this analysis. However, it can be concluded that structural health monitoring should be an important part of life-cycle management of flood defences.