Geometric Nonlinearity Effect on Seismic Behavior of High Arch Dams

Abstract

In this research, geometrically nonlinear dynamic analysis of arch concrete dam is attempted. At first, suitable models for large deformation analysis of massive plain concrete structures are investigated and by considering arch dam special features and properties, proper model for large displacement analysis is developed. A nonlinear analysis of the Dez arch dam using the engineering stress -strain model for large displacements is carried out under MCE ground motion. Fluid-Structure interaction is modeled including water compressibility and reservoir bottom absorption and the rock foundation is modeled as a mass-less flexible medium. Joint nonlinearity is also taken into consideration in the analysis. The penetration of water in opening joint during the earthquake is also considered and the significance of nonlinear geometry effects when accompanied by hydrodynamic pressure in joints is investigated. It is indicated that considering large deformation effects could be magnified when water penetration into opening joints is permitted. The obtained results showed that because the structural behavior of an arch dam does not allow large strains in a general manner, one can rule out the appearance of large displacements in the models including linear material.