Evaluation of the effect of reservoir length on seismic behavior of concrete gravity dams using Monte Carlo method

In present study, the effect of reservoir length on seismic performance of concrete gravity dam has been investigated. Monte Carlo probabilistic analysis has been used to achieve a sensitivity of the responses to variation of truncated reservoir length in finite element model. The ANSYS software based on finite element method is applied for modeling and analysis. The Pine Flat dam in California, under components of El Centro, San Fernando and North Ridge earthquake, is modeled as a case study to evaluate the effect of reservoir length on seismic behavior and optimization. The foundation flexibility has been considered in modeling and Sommerfeld boundary condition has been used for reservoir truncated boundary condition. In Monte Carlo probabilistic analysis, the reservoir length has been considered as input variable and maximum dam crest displacement, maximum hydrodynamic pressure in reservoir and maximum tensile principal stress in heel and compressive principal stress in toe of dam have been selected as output parameters. The Latin Hypercube sampling method has been applied with unique distribution function for input variable.  Obtained results show the sensitivity of output responses to variation of reservoir length. Considering sensitivity results, it is possible to select the optimum length of reservoir for finite element model.