Performance Evaluation of Monte Carlo Simulation and FORM Method to Calculate Probability of Failure for Concrete Gravity Dams in Sliding Failure Mode under Static Loading

Authors
F. MiarNaeimi 1
G. Azizyan 2
G. Akbari 3
1 PhD Student/University of Sistan and Baluchestan
2 University of Sistan and Baluschestan
3 University of Sistan and Baluchestan
Abstract
Failure of a concrete gravity dam will cause unavoidable human loss and financial damages. In this study SARIYAR concrete gravity dam, located in turkey was chosen as a case study and its probability of sliding failure in various condition was studied. The most important reason in sliding failure of a concrete dam was lateral and uplift loads, caused by increase in the level of reservoir water. Different scenarios were considered in which might happen for a dam, all the possible height of reservoir water simulated. Afterward, Probability of failure and reliability index was calculated with Monte Carlo simulation and FORM method in all conditions and comparison with each other. The influence of the Number of Simulations (NOS) in the Monte Carlo method was also discussed. Results showed that, in some cases, the resistance of the system was much more than the loads and limit state function had a significant distance from samples. In such states, Monte Carlo was unable to calculate the probability of failure with each NOS but FORM method obtained the Reliability Index (β) in these situations. It became clear that these values were far from reality. With increase in the forces, responses from Monte Carlo had a high degree of precision. The probability of failure generated by FORM method was less than a reality. Failure of a concrete gravity dam will cause unavoidable human loss and financial damages. In this study SARIYAR concrete gravity dam, located in turkey was chosen as a case study and its probability of sliding failure in various condition was studied. The most important reason in sliding failure of a concrete dam was lateral and uplift loads, caused by increase in the level of reservoir water. Different scenarios were considered in which might happen for a dam, all the possible height of reservoir water simulated. Afterward, Probability of failure and reliability index was calculated with Monte Carlo simulation and FORM method in all conditions and comparison with each other. The influence of the Number of Simulations (NOS) in the Monte Carlo method was also discussed. Results showed that, in some cases, the resistance of the system was much more than the loads and limit state function had a significant distance from samples. In such states, Monte Carlo was unable to calculate the probability of failure with each NOS but FORM method obtained the Reliability Index (β) in these situations. It became clear that these values were far from reality. With increase in the forces, responses from Monte Carlo had a high degree of precision. The probability of failure generated by FORM method was less than a reality. Failure of a concrete gravity dam will cause unavoidable human loss and financial damages. In this study SARIYAR concrete gravity dam, located in turkey was chosen as a case study and its probability of sliding failure in various condition was studied. The most important reason in sliding failure of a concrete dam was lateral and uplift loads, caused by increase in the level of reservoir water.

Keywords

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Modares Civil Engineering journal
Volume 16, Issue 3
September and October 2016
Pages 227-240