Handling Accidents and Calamities in Hydraulic Structures – Objectives of Pianc Working Group WG-241

Abstract While the prior objective of hydraulic structures (such as lock gates, navigation river weirs and storm surge barriers) is to remain in service, engineers must also be capable to adequately handle their failures. Despite the ongoing development of expertise, design tools, norms, and construction methods, there are still a considerable number of accidents and calamities that happen to such structures. In addition, the losses and costs of damages as result of these so-called “upset events” are growing due to the growing complexity of waterborne infrastructure, intensity of navigation or other utilization of inland waters. Accidents to hydraulic structures happen not only when their loads exceed the design strength. Other possible causes are, for example, unforeseen conditions, lack of inspection and maintenance, improper operation, and navigation errors. These other causes of accidents are often less controlled by technical norms than the relations between loads and resistances of structures. In addition, there are often combinations and complex sequences of events that may lead to disastrous results. So far, various PIANC Working Groups have provided guidance for preventing accidents from happening, e.g. PIANC (2019) and PIANC (2020), including the accidents resulting from ship collision, e.g. PIANC (2014) and PIANC (2018). While this should remain the engineer’s main concern, there is also a demand for more guidance how to effectively handle the accidents and calamities that actually happen. This is a matter of combined effort of not only engineers. Nevertheless, engineers can and should contribute to the solutions in such cases. Therefore, a new PIANC InCom Working Group has been established to investigate the existing practices in handling accidents and calamities; and to provide guidance in this field for professionals involved. This paper presents the objectives of the Working Group, selected investigation approach, some preliminary investigation results, and the envisioned contents of the final report.