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Seismic Reliability and Global Sensitivity Analysis of Concrete Gravity Dams

Houshmand Khaneghahi, Mohammad | 2017

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 49498 (09)
  4. University: Sharif University of Technology
  5. Department: Civil Engineering
  6. Advisor(s): Ghaemian, Mohsen; Toufigh, Vahab
  7. Abstract:
  8. This research investigated the seismic performance of gravity dam in the reliability and sensitivity analysis framework under earthquake loading. The performance criteria were defined using crest displacement and tensile stress. The uncertainty due to the material properties of the dam was considered for the reliability approach, in addition to the different ground motion intensity levels for parametric analysis. The exceedance probability of the limit-state functions was computed for varying threshold values through Mean-Value Second-Moment, First-Order Reliability Method and improved Latin Hypercube sampling. Approximation methods were applied along with the sampling method for considering the different levels of accuracy and perform sensitivity analysis. Local sensitivity analysis, based on FORM, indicated that the relative importance of random variables for miscellaneous limit-state, ground motion intensity, and threshold values. Moreover, Sobol’ indices were determined in the global sensitivity analysis framework. The importance measures based on the local sensitivity analysis were not considered as reliable since they varied through different limit-state thresholds. Moreover, local sensitivity analysis for seismic analysis was inappropriate. Contrarily, Sobol’ indices suggested a good agreement between the models with different sample numbers and different intensity measures of seismic excitation. In addition, the distribution of displacement and stress responses associated with the input random variables were determined
  9. Keywords:
  10. Concrete Gravity Dam ; Latin Hypercube Sampling (LHS) ; Sensitivity Analysis ; Seismic Reliability Analysis ; Local Sensitivity Analysis ; Sobols Indexes ; Global Sensitivity Analysis

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