Time-variant finite element reliability for performance degradation assessment of concrete gravity dam

A time-variant reliability method based on finite element reliability theory is introduced to evaluate the safety and reliability of a concrete gravity dam at Shenwo reservoir in Liaoning. The deterministic responses of representative sluice piers are computed through static pushover and dynamic analyses. For time variant case, the earthquake history is simulated by using a random process, and the FORM approximation combined with Koo's analytical solution is used to compute the mean upcrossing rate for a given performance function, through which the failure probabilities are calculated. Based on the analysis results using this uncertain method, the current safety and reliability for this gravity dam are evaluated. In addition, deterministic responses of the dam at its current state are presented with that in the original state to quantify its performance degradation. Finally, the assessment results are discussed. All the computation is performed using an open finite element analysis platform for earthquake engineering simulation, called as OpenSees.