Failure probability analysis of storm surge barriers

The Directorate-General for Public Works and Water Management (Rijkswaterstaat) manages six movable storm surge barriers that play an essential role in protecting the hinterland from flooding. To ensure the timely closure of the barriers during heavy storms and their correct reopening afterwards, the Directorate-General for Public Works and Water Management has called on the expertise of Iv, NRG and Delta Pi. Iv carries out failure probability analyses, actualises them, participates in specific failure probability studies, and evaluates and contributes to the half-yearly failure probability reports for the storm surge barriers. The work goes beyond the technical condition of the barriers. For example, Iv is also involved in developing the so-called KOMPAS, a tool developed by the Directorate-General for Public Works and Water Management to assess the softer (mainly organisational) aspects of risk-based management and maintenance of the storm surge barriers.

While it is impossible to provide a 100% guarantee that storm surge barriers will always function flawlessly, our challenge is to minimise the probability of failure. These failure probabilities are determined using an integral risk approach and are set as standards in the Water Act.

Failure probabilities are recalculated and reported at least twice yearly to comply with safety standards. To this end, various failure probability analyses of the barriers are performed in the form of Failure Mode, Effect and Criticality Analyses (FMECAs), fault tree analyses, external event analyses (including risks such as. fire, lightning, a collision, etc.), human failure, software failure and common cause failures. These analyses require specialised failure probability expertise to prepare them, correctly interpret the outcomes, and make decisions on the storm surge barriers’ management, maintenance, and system modifications.

This project contributes to guaranteeing safety against flooding in the Netherlands, both now and in the future. The probability of failure is minimised by carrying out failure probability analyses.