The Malpasset Dam failure

The failure of Malpasset Dam, in 1959, was the first failure of an arch dam. And, astonishingly, it was designed by Andr~ Coyne, the great master, responsible for the design of more than a hundred dams (Fig.l). Court trials, in several jurisdictions and with various panels of experts, lasted for six years, and concluded that the cause of the failure was unpredictable. Many specialists and laboratories contributed to the investigations after the failure. As early as the next day, Andr~ Coyne assigned a solemn duty to his close assistants: to discover the mechanisms which led to the failure so as to warn the designers of the future and avoid the reoccurrence of the same catastrophe. After six years of research an explanation was proposed and published. This explanation, based on uplift in the foundations, was accepted almost unanimously by the profession. However, some different ideas are still expressed by a few persons. It is also important to recall that the uplift explanation has never been proposed as a certainty, but no other has succeeded in satisfying the observed facts so thoroughly. The main purpose of this workshop is to try and decide what is certain, what is not and what additional research work is required. This paper will serve as a starter for the discussion. It summarises most of the data published to date without repeating all the details. The main publications to which it is necessary to refer are Bellier (1967), Bernaix (1967), Mary (1968) and Bellier et al. (1970). An effort is made to present facts as objectively as possible and to refrain from arguing against " theories" considered as erroneous. In order to achieve the main objective of this workshop, i.e. to obtain a consensus of the profession on the basic causes of the failure, a high degree of impartiality is required from all those who will participate in the discussion and contribute to the establishment of the truth.