Seismic Assessment of Concrete Dams, Considering Anisotropy Caused by Lift Joints

Concrete dams are anisotropic due to lift joints that affect their performance. Lift joints are usually ignored in numerical analyses of concrete dams and the dam body is assumed to be homogeneous and isotropic.  In this study, the seismic behavior of gravity dams was evaluated considering the anisotropy caused by lift joints, and the orthotropic and isotropic state responses were compared. Moreover, in the seismic loading range, a more detailed evaluation was done by applying the real effects of strain rate. Koyna concrete gravity dam was selected for the case study. The results showed that concrete anisotropy leads to larger dynamic displacements and greater damage to the dam body. By considering the orthotropic properties of concrete can lead to more realistic results. The maximum compressive and tensile stresses also increased in the anisotropic model compared to the homogeneous and isotropic model, indicating the usefulness of incorporating the orthotropic behavior of concrete in seismic analysis. In addition, considering the strain rate in the seismic loading range had an insignificant effect on the results. Therefore, considering the large dynamic increase factor in numerical analyses causes the error.