Intake towers, essential for hydraulic hub projects, are integral to maintaining safety and efficiency, especially under seismic conditions that are prevalent near fault zones. These structures are vital for the integrity of hydraulic hubs, effective hydropower generation, and downstream safety. The duration of seismic events notably influences the towers’ structural response. In light of China’s initiative to build numerous high dams and large reservoirs, understanding the interplay between seismic duration and the intake tower response is crucial. This study, utilizing a duration-dependent composite parameter method based on seismic intensity, investigates the impact of near-fault ground motion duration effects on the response characteristics of intake towers. It analyzes the correlation between three types of six duration parameters and six duration-related composite parameters with the nonlinear seismic response of the physical model of the intake tower structure, as well as the rapid seismic response of the simplified model. This study investigates the impact of near-fault ground motion duration on intake towers, which is crucial for hydraulic hub projects, particularly in seismic-prone areas like those targeted by China’s dam construction initiative. Utilizing a duration-dependent composite parameter method, the study establishes a strong correlation between seismic duration parameters and the nonlinear response of intake towers, emphasizing the significance of uniform duration-related composite intensity parameters for characterizing near-fault seismic motion features. The findings reveal a pronounced correlation between the elasto-plastic response of intake towers and consistent duration-related composite strength parameters, offering crucial insights for optimizing structural design and enhancing seismic response assessment, particularly in the realm of large-scale dam projects.

The present study proposes a variable replaceable link for high-strength steel frames with Y-eccentric braces designed to effectively dissipate earthquake energy by confining plastic deformation to its central zone. This unique feature allows for easy post-earthquake recovery or replacement. To investigate the seismic performance of such structures, a comprehensive finite element numerical parametric analysis is conducted using ABAQUS software. Various parameters, including the length of the central zone, replaceable link length, span, and steel grade are considered to optimize the structural design. This study examines the failure modes, hysteretic behavior, bearing capacity, plastic rotation of the replaceable link, and ductility of structures under cyclic loading. The results indicate that reducing the span and utilizing high-strength steel significantly enhance the ductility and ultimate bearing capacity of the structure. This approach also reduces the cross-sectional dimensions, saves steel material, and limits the development area of plasticity, thereby facilitating post-earthquake repair of links after rare earthquakes. An optimal length of the link improves the structural stiffness and energy dissipation capacity. However, if it is too short or too long, it complicates post-earthquake repairs and impairs energy dissipation performance. The conclusions drawn from this research aim to provide valuable insights and theoretical foundations for future structural designs.

This study selected a simplified water intake tower model, simplifying the physical structure into a cantilever model, and MATLAB software (R2010b) was used to develop a rapid seismic response analysis program for the structure. Thirty near-fault pulse and non-pulse ground motions were selected as the input ground motions for this analysis. Peak ground velocity (PGV) was used as the intensity parameter for the ground motions. The acceleration, cross-sectional rotation, and lateral curvature of the simplified water intake tower model were calculated for ground motions modulated with different PGA amplitudes. The acceleration, maximum shear force, and cross-sectional rotation of the simplified water intake tower model were also calculated for ground motions modulated with improved effective peak acceleration (IEPA) and improved effective peak velocity (IEPV). The study showed that the seismic response of the simplified water intake tower model for near-fault ground motions modulated with different intensities of PGV amplitude modulation was closer to the unmodulated response order. PGV as an intensity parameter did not affect the acceleration response amplification factor of the water intake tower and hoist chamber. The AC coefficient indicated that PGV was less suitable for pulse-type earthquake amplitude modulation than PGA. Compared with PGA amplitude modulation, IEPA amplitude modulation is more suitable for pulse-type seismic motion, while IEPV amplitude modulation has less impact on pulse-type seismic motion.