The seismic design and dynamic analysis of high concrete gravity dams is a challenge due to the dams’ high levels of designed seismic intensity, dam height, and water pressure. In this study, the rigid, massless, and viscoelastic artificial boundary foundation models were established to consider the effect of dam–foundation dynamic interaction on the dynamic responses of the dam. Three reservoir water simulation methods, namely, the Westergaard added mass method, and incompressible and compressible potential fluid methods, were used to account for the effect of hydrodynamic pressure on the dynamic characteristics and seismic responses of the dam. The ranges of the truncation boundary of the foundation and reservoir in numerical analysis were further investigated. The research results showed that the viscoelastic artificial boundary foundation was more efficient than the massless foundation in the simulation of the radiation damping effect of the far-field foundation. It was found that a foundation size of 3 times the dam height was the most reasonable range of the truncation boundary of the foundation. The dynamic interaction of the reservoir foundation had a significant influence on the dam stress.

In the assessment of the seismic performance of ultrahigh‐arch dams, challenges such as complex structural models, extensive degrees of freedom, and extended computation times are commonly encountered. Consequently, there is a pressing need to develop a more streamlined and effective approach for investigating the seismic behavior of ultrahigh‐arch dams. The endurance time method, a novel approach in seismic analysis, is increasingly favored for the dynamic analysis of large structures. In this study, the dynamic damage characteristics of an ultrahigh‐arch dam are analyzed based on the endurance time method, and the seismic fragility analysis is evaluated. Utilizing a case study of an ultrahigh‐arch dam in southwest China, a comprehensive three‐dimensional nonlinear model encompassing dam, bedrock, and water interactions is developed. This model incorporates considerations of dam and bedrock damage, cracking, dynamic behavior of contraction joints, and the interaction between the dam and reservoir water. The nonlinear least‐squares function is used to generate three endurance time acceleration functions (ETAFs) based on the response spectra of the hydraulic structure seismic design standard. The dynamic analysis of the above model is carried out by using the endurance time method and the incremental dynamic analysis (IDA) method. The results indicate that the endurance time method can well reflect the fragility of ultrahigh‐arch dams under different intensities of ground motions, with significant computational efficiency.

Intake towers as the entrance of spillway or diversion system constitute the most common structural configuration in large water conservancy and hydropower engineering. The safety and functional capability of intake towers in the event of a major earthquake are crucial, since the controlled release of the reservoir could help to prevent catastrophic failure of a dam after an earthquake by reducing the hydrostatic loads. Therefore, the seismic capacity of intake towers is a key technical issue. In this paper, giving proper consideration to the dynamic interactions of the main tower with the hoist chamber, reservoir, and foundation effects of the fluid-structure interaction on dynamic responses of intake towers and seismic whiplash effects of hoist chambers were studied. Based on a practical project, potential-based fluid elements were employed to analysis and investigate the effects of the reservoir compressibility on natural vibration characteristics of the integral structure, hydrodynamic pressure, and seismic responses of the main tower and hoist chamber.