Many concrete gravity dams with discontinuous geometry along their longitudinal axis have suffered important structural damage particularly in the area of the discontinuity. These damages are mainly characterized by the deterioration and the cracking of the concrete at this location. The observed damage is caused by the static and thermal loads and by the longitudinal effects that lead to a stress concentration at the discontinuity. However, the three-dimensional seismic behaviour of dams with discontinuous geometry along their longitudinal axis have not been studied rigorously in the past. The main objective of this research is to investigate the effects of static, thermal and seismic loads on the structural behaviour of concrete gravity dams considering the discontinuous configurations.;To accomplish this objective, three-dimensional static, thermal and seismic parametric analyses have been conducted using linear finite element models. Three different geometries are studied: a straight dam and two geometrically discontinuous models with 140 and 220 degree angles between the two straight segments measured in the upstream direction. These models, of 35 m in height and 250 m in length, represent typical dams found in the province of Quebec.;The present investigations have shown that the thermal load is mainly responsible for the observed damages, followed in order of importance by the seismic and static loads. This study has also shown that, an accute angular discontinuity of 140 degrees is not efficient to develop an arch effect as opposed to the behaviour generally observed with an angle of 220 degrees. Due to the lack of arch action, the former geometry of dam is likely to encounter serious damage in the upper part of an interface zone at the discontinuity.
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