Design and Performance Analysis of a Vibration Reduction Scheme Using a Tuned Mass Damper for Prestressed Piers under Flood-Earthquake Coupling Action

Abstract

The coupling effect of flood discharge and earthquake places the prestressed gate pier in an extremely complex stress state, making it difficult for traditional design methods to meet the safety requirements of sluice projects in high seismic zones. In this paper, a tuned mass damper (TMD) vibration reduction scheme is designed for the dynamic response characteristics of prestressed gate piers under flood discharge-earthquake coupling conditions, and its vibration reduction performance is systematically analyzed through numerical methods. First, based on structural dynamics theory, the optimal frequency ratio and damping ratio of the TMD are determined, and a vibration reduction device with a mass of 2000 kg, a stiffness of 1.5×10⁵ N/m, and a damping coefficient of 4.2×10³ N·s/m is designed. Then, a three-dimensional finite element model of the prestressed gate pier is established using ANSYS, where the mechanical behavior of the TMD is simulated using spring elements and mass points, and the variation patterns of dry and wet modal frequencies of the gate pier before and after TMD installation are analyzed. Finally, two typical working conditions—the check flood-earthquake coupling condition and the normal earthquake condition—are selected to calculate the time-history responses of gate top displacement and maximum principal stress in the gate pier, and to evaluate the vibration reduction effect of the TMD and its spatial distribution. The results show that after TMD installation, the natural frequencies of each order of the gate pier decrease, with higher-order frequencies significantly decreasing and becoming denser, which is beneficial for broadening the vibration reduction frequency band. Under the most unfavorable working condition, the dynamic displacement at the gate top decreases from 4.81 mm to 2.08 mm, achieving a reduction rate of 56.7%, and the maximum dynamic tensile stress decreases from 0.57 MPa to 0.53 MPa, a reduction of approximately 7.0%. The vibration reduction effect exhibits a clear spatial distribution characteristic: the reduction rate at the top nodes of the gate pier is about 58%–60%, that at the middle nodes drops to 24%–25%, and that at the bottom nodes is only about 8%. The TMD vibration reduction scheme designed in this paper has a significant control effect on the displacement response of prestressed gate piers and can provide a reference for the seismic design of similar sluice projects in high seismic zones.