Efficient and practical seismic control of structures-particularly through isolation systems-remains a significant challenge due to high implementation costs and construction complexity. Moreover, their application in retrofitting existing structures often requires extensive modifications.To address these challenges, this study proposes a novel and cost-effective seismic control system, termed the Ridge-Isolated Tuned Mass Damper (RITMD), which integrates the advantages of tuned mass damping and seismic isolation. A reduced-order two-degree-of-freedom (2DOF) model is developed to capture the coupled dynamic behavior of the primary structure and the RITMD system. An optimization framework based on the Particle Swarm Optimization (PSO) algorithm is employed to determine the optimal tuning parameters. Subsequently, closed-form design expressions are obtained using nonlinear regression analysis to facilitate practical engineering applications .The proposed approach is further extended to three-dimensional structural systems, and its performance is evaluated through nonlinear time-history analyses under bidirectional earthquake excitations. The results demonstrate that the RITMD system significantly reduces structural responses, including displacements, accelerations, inter-story drifts, torsional demands, and their corresponding root-mean-square (RMS) values.Overall, the proposed system provides an efficient, practical, and versatile solution for enhancing the seismic performance of both new and existing structures.
An inerter is a two-terminal mechanical element capable of generating a force proportional to the relative acceleration between its terminals, thereby enhancing the inertial effect in structural systems. The integration of an inerter with a Tuned Mass Damper (TMD) forms a Tuned Mass Damper Inerter (TMDI) system, which has the potential to improve vibration control performance under seismic excitation. This study aims to evaluate the effect of implementing TMDI on the dynamic response of building structures. The optimal design parameters of the TMDI were determined numerically by varying the frequency ratio (f) and damping ratio (ξ) based on the minimization of structural displacement response. The structural model analyzed in this study is a 12-story building equipped with a TMDI connected between the top floor and several lower floors. The analysis was conducted using a 12-story MDOF model based on MATLAB, with parameter optimization performed using the fminimax function and time-history evaluation under several earthquake records. The results show that connecting the TMDI to at least the 6th floor can reduce the structural responses in terms of displacement, acceleration, and velocity by approximately 50%, 41%, and 36%, respectively, compared with the structure without an inerter. In addition to providing greater response reduction, the TMDI system requires a smaller additional mass compared with a conventional TMD. To achieve approximately 20% response reduction, the TMDI requires a mass that is about four times smaller than that required by a TMD.
This study investigates the seismic behaviour of a 10-storey shear-type building subjected to eleven near-field earthquake records while explicitly accounting for nonlinear soil-structure interaction (SSI). To improve seismic performance, a novel multiple active friction-tuned mass damper (MAFTMD) framework is proposed by integrating multiple friction-tuned mass dampers (MFTMDs) with an enhanced integral-derivative tilted (I-DT) control strategy. The nonlinear behaviour of the supporting soil is represented using the Hardin-Drnevich model, enabling strain-dependent stiffness degradation and damping effects to be captured under stiff, soft, and very soft soil conditions. The parameters of the MTMD and MFTMD configurations, along with the gains of the enhanced I-DT controller implemented in the MAFTMD system, are optimized using a multi-objective thermal exchange optimization (MOTEO) algorithm. The optimization simultaneously minimizes peak storey displacement and acceleration while satisfying inter-storey drift ratio constraints. The results demonstrate that incorporating friction mechanisms significantly enhances energy dissipation and structural response mitigation as compared to conventional MTMD systems. Furthermore, the proposed MAFTMD framework provides the most stable and effective overall performance under varying near-field earthquake characteristics and nonlinear soil conditions. The study also shows that nonlinear SSI strongly affects the performance and optimization of structural control systems. Overall, the proposed framework combines friction-based damping, active control, and nonlinear soil modelling to improve the seismic performance of mid-rise buildings under near-field earthquakes.
Morteza Akbari, M. Seifi, T. Falborski et al.· Archives of Civil and Mechan...· 0 citations
To enhance the seismic damping effect of connected structures under intense seismic activities, this study introduces a novel control system for connected structures. This system strategically places the damping layers at different locations within the main towers to mitigate the violent system response of the connected structure during rare earthquakes. The double-sided damping structure mainly involves arranging damping layers in the towers on both sides of the connected structure. The damping layers use lead-core isolation bearings (LRB), which fully combines the concepts of damping and isolation. It applies isolation technology to the damping system of high-rise structures, and can effectively solve the technical problem of overturning when isolation technology is applied to high-rise buildings in engineering experiments. The structure is modeled using ABAQUS. Models for both single-sided and double-sided damping structures are established and subsequently compared with the seismic resistance structure. This comparison is conducted to analyze the time-history response of layer shear, base reaction force, top-layer acceleration, and interstory drift of various structural models under rare earthquakes. Additionally, shear-drift hysteresis curves of the damping layer are constructed to evaluate the energy dissipation rate of the structure’ s damping layer using an energy analysis method. The results show that both damping structures exhibit superior energy dissipation and damping effects. However, the introduction of an additional damping layer in the double-sided damping structure results in a more obvious damping effect and a higher energy dissipation rate. The risk of overturning due to excessive bending deformation of the superstructure is mitigated by designing the location of the damping layer. However, the control effect of both damping structures on vertical earthquakes is not obvious, and further research is needed.
Viscoelastic dampers, leveraging the synergistic mechanism of viscous dissipation and elastic recovery, simultaneously reduce seismic-induced structural displacement and acceleration responses while offering the advantages of simple construction and ease of installation, which hold broad prospects in both the seismic design of new buildings and the retrofitting of existing structures. This work aims to propose a rapid optimization design method for viscoelastic dampers considering torsional effect for three-dimensional solid structures. First, a full-scale prefabricated assembled viscoelastic damper was developed, and mechanical property tests were conducted under a series of loading conditions. Based on the test results, a genetic algorithm is employed to optimize the design scheme of viscoelastic dampers through co-simulation using MATLAB R2022a and OpenSees. The optimization objectives consider both the inter-story drift ratio and acceleration response of the structure, with particular emphasis on the influence of torsional effects. Given that the proposed optimization scheme accounts for structural dynamic characteristics, building functionality, and the universality of seismic excitations, it serves as a design reference for the optimization analysis of other damped structures.
Teng Ge, Wangwang Fang, Zhong-wei Hu et al.· Applied Sciences· 0 citations
The application and performance-oriented parameter optimisation of an overload-protected viscous damper (OP-VD) are investigated in this study to mitigate seismic responses and prevent excessive force transmission between adjacent structures. Within a performance-based seismic design framework, the damper parameters are systematically optimised to ensure that multiple response objectives are satisfied under varying seismic intensities. The OP-VD integrates a frictional overload protection mechanism with viscous energy dissipation, enabling an adaptive control strategy. This design ensures that damper forces are effectively capped under strong ground motions, while sufficient damping is provided under moderate excitations to control inter-storey drift and absolute structural acceleration. The mechanical characteristics and working principle are first clarified through detailed implementation and simulations. Subsequently, a coupled dynamic model of adjacent structures interconnected by the proposed damper is established for non-linear time-history analyses. Numerical simulation results demonstrate that under severe seismic inputs, the OP-VD successfully limits force transfer by way of the activation of the overload protection mechanism, thereby preventing structural overloading. In contrast, under moderate excitations, the viscous component dominates, leading to enhanced vibration attenuation. Consequently, the device achieves a balanced control of drift, acceleration and force demands, ensuring both structural safety under rare earthquakes and serviceability under frequent events.
Yuan Jiang, Shiming Zhang, Ming Li et al.· Proceedings of the Instituti...· 0 citations
Wind turbines in seismically active regions are increasingly vulnerable to earthquake-induced vibrations due to their growing height and flexibility. Effective vibration control is therefore essential to ensure structural safety and operational reliability. This study examines the performance of a novel compact nonlinear magnetic damper with non-contact restoring and damping force generation in mitigating the seismic response of wind turbine towers. The tower is modeled through a three-degree-of-freedom modal representation, corresponding to the first three fore–aft mode shapes obtained from a finite element–based modal analysis. A synthetic acceleration record was then developed by averaging the frequency content of five well-known earthquakes to represent their dynamic characteristics, providing a comprehensive excitation spectrum for evaluation. The damper parameters were optimized using a Bayesian optimization framework, with the root-mean-square of tower-top displacement adopted as the objective function. The optimized configuration was subsequently assessed under each individual earthquake record to evaluate its robustness. Results show that the proposed damper, together with the optimization scheme, achieves 36–65% reductions in RMS tower-top displacement and maintains consistent performance across different ground motions. The findings demonstrate the effectiveness and adaptability of the magnetic damper in enhancing the seismic resilience of wind turbine structures and provide a promising direction for integrating smart damping technologies into renewable energy systems.