UNCERTAINTY IN SAFETY EVALUATION OF CONCRETE DAMS NW-IALAD - PRELIMINARY FINDINGS (EU-NETWORK - INTEGRITY ASSESSMENT OF LARGE CONCRETE DAMS

The integrity and safety assessment of concrete dams plays an important role for the infrastructure of many states of the EU (European Union). However, the water reservoirs created by those dams are often considered as a potential hazard. The safety of these important structures is of great concern to the owners, operators and engineers as well as to the public. This was the motivation to establish a thematic network, which brings together government authorities, researchers and end users to conduct a state of the art review on the integrity and safety assessment practice for concrete dams. The thematic network NW-IALAD is funded by the European Commission and responds to the specific EU program promoting competitive and sustainable growth. The aims of the network are to compare and critically review the current practice of dam operation, maintenance, rehabilitation and of the safety assessment in different European countries and to conduct a systematic comparison of available models for the numerical simulation of the structural behavior of concrete dams (benchmarking). Based on the results of the state of the art review shortcomings and prevailing deficits are pointed out. Preliminary results show the need for improvement. Suggestions for future plans and strategies apt to enhance the current practice are developed. The results of the NW-IALAD outcome can be differentiated into several topics: 􀂾 Dam operation, maintenance, repair and incidents 􀂾 Dam surveillance and dam performance 􀂾 Numerical tools for the simulation of concrete dams and dam foundation under several load conditions 􀂾 Dam safety and integrity assessment For a safe operation of our dams a close co-operation of all stakeholders is required. For the safety and integrity assessment a sound basis is necessary which comprises a comprehensive documentation of the dam history including the planning, design, construction and operation phases. Based on this reliable numerical models need to be applied that are able to simulate normal operational and extraordinary load conditions. These models continuously need to be verified with the actual readings of the dam surveillance data. Ageing of the structure needs to be taken into account and necessary maintenance and rehabilitation measures need to be carried out. Qualified personnel at all levels are an absolute requirement.