ABSTRACT To overcome the limitation of traditional metallic dampers in adapting to uncertain earthquake intensities, this study proposes a parameter design method for a four‐stage graded‐yield metallic damper based on the starfish optimization algorithm (SFOA). The SFOA utilizes a comprehensive evaluation function based on interstory drift angle and floor acceleration as performance metrics. According to this algorithm, optimal mechanical parameters for conventional single‐yield‐point dampers under frequent, moderate, rare, and extreme earthquakes were obtained. Then, these parameters formed the basis for constructing the backbone curve and hysteretic model of a four‐stage graded‐yield damper. The nonlinear time‐history analysis results show that the vibration reduction effect of a nine‐story steel frame installed the four‐stage graded‐yield damper under different seismic intensity levels is nearly equivalent to that of every optimal single‐yield‐point damper corresponding to each seismic level. Finally, compared with the optimized single‐yield‐point damper in moderate earthquake, the proposed four‐stage graded‐yield damper can provide superior seismic response control under frequent, rare, and extreme events, respectively. This study proposes a method for determining the optimal design parameters of a four‐stage graded‐yield damper and its hysteresis model construction method, which verifies their effectiveness and has important engineering application value.
ABSTRACT A SAP2000 finite element model was established to simulate the effect of concrete shrinkage and creep on structural deformation of a supertall building C1 tower. According to the construction process, gradually activate the structural units of each construction step to simulate the construction process of supertall structures layer by layer; the results show that during the construction phase, the deformation caused by shrinkage and creep can account for about half of the total deformation. The deformation values calculated by different shrinkage and creep calculation modes vary during the construction phase. The calculation results of CEB‐FIP mode and ACI mode are very close, whereas the GL2000 model has a larger calculation value; in the use stage, vertical deformation is still developing, and the deformation value after 20 years of completion can reach twice that of the initial completion. The vertical deformation difference has increased by about 60%, and the main development period of vertical deformation of the structure is within 20 years of completion; the redistribution of internal forces caused by shrinkage and creep continuously reduces the axial force of the bottom frame column, but the reduction is small, with a maximum of only about 5.7%. The study's originality lies in integrating staged construction simulation with time‐dependent material behavior for a supertall structure and in providing engineering‐oriented comparisons of three international shrinkage–creep models, offering practical reference for deformation control and long‐term performance assessment.
ABSTRACT The seismic fragility assessment of high‐rise buildings, particularly those employing braced tube steel structural systems, requires comprehensive analysis of their dynamic response to intense near‐fault ground motions. These seismic events present unique challenges due to their distinctive characteristics, including distinct velocity pulses and considerable vertical ground motion component. Belt trusses represent a promising engineering intervention to enhance lateral stiffness, optimize load distribution, and mitigate seismic effects in high‐rise structures. This study investigates the quantitative impact of positioned belt trusses on the seismic fragility of high‐rise braced tube steel structures under near‐fault ground motions. A code‐designed 30‐story braced tube steel frame was analyzed in two configurations (i.e., with and without top‐level belt trusses) to assess the related influences on seismic performance and fragility characteristics. The methodology employed incremental dynamic analysis (IDA) using an ensemble of 14 ground motion records, specifically selected for their strong near‐fault, pulse‐type characteristics. Seismic fragility is quantified through nonlinear dynamic analysis using interstory drift ratios as the damage measure, with limit states defined based on established structural performance levels. This research results demonstrate that the integration of belt trusses not only enhances seismic performance under strong near‐fault ground motions but also significantly reduces the overall structural system fragility. Furthermore, the implementation of belt trusses promotes more efficient load distribution patterns and improves energy dissipation mechanisms throughout the structure, contributing to enhanced seismic resilience.
ABSTRACT The wind turbine tower, a typical thin‐walled structure, is susceptible to buckling under dynamic loads, particularly during seismic events. The dynamic buckling behavior of wind turbine towers under near‐fault and far‐fault ground motions is investigated herein. A 2‐MW wind turbine located in northwestern China was selected as the prototype, with the blades and nacelle modeled as concentrated masses. For incremental dynamic analysis (IDA), 42 natural ground motion records were employed as input excitations, classified into three categories based on epicentral distance and pulse characteristics: 14 near‐fault pulse‐like ground motions, 14 near‐fault non‐pulse‐like ground motions, and 14 far‐fault ground motions. The dynamic buckling behaviors were analyzed by using phase plane trajectories and the Budiansky–Roth (B–R) criterion. A ductility factor accounting for dynamic buckling effects was developed. Local plastic dynamic buckling at the lower section of the turbine doorway was identified as the primary failure mode. Under near‐fault ground motions, dynamic buckling is primarily governed by geometric nonlinearity, whereas buckling induced by far‐fault ground motions predominantly influenced by both plastic deformation and geometric nonlinearity. Pulse‐like ground motions demonstrate a higher propensity to induce dynamic buckling compared to non‐pulse‐like ground motions. At a 90% reliability level for elastoplastic deformation capacity, the ductility factors are 7.41, 9.48, and 3.80 for near‐fault pulse‐like, near‐fault non‐pulse‐like, and far‐fault ground motions, respectively.
ABSTRACT With the increasing demand for high wind turbine towers, precast concrete towers have been widely used as an economical and applicable form. This paper proposes a calculation method for the detachment range and contact stress of horizontal joints in precast circular towers, considering the issue of horizontal joint detachment. A convenient table for designers is summarized. By determining the four parameters of the inner diameter, outer diameter, vertical force, and bending moment of the circular cross‐section, the detachment range and the maximum contact stress of horizontal joints can be calculated using the table lookup method. The detachment range and the maximum contact stress are usually the two most concerned parameters for designers. Subsequently, the proposed calculation method is validated by comparing with the finite element simulation results and the calculation results brought by other scholars. Finally, this paper also explores the effects of vertical joints and torque load on the detachment range and contact stress of tower horizontal joints, pointing out that considering both vertical joints and torque load will significantly weaken the integrity of the tower. Therefore, it is necessary to strictly connect the vertical joints of precast segmented towers to limit the relative displacement and separation.
ABSTRACT Seismic pounding against moat walls (MWs) may occur in seismically base‐isolated buildings equipped with insufficient isolation clearances, especially during strong pulse‐like earthquakes. Serious MW pounding significantly amplifies the story drifts and floor accelerations of the superstructure, impairing structural isolation effectiveness. Hence, various passive gap dampers (GDs) have been developed in isolation systems to provide adaptive deformation mitigation, accommodating multiple earthquake intensities. This study comprehensively investigates the seismic performance of adaptive base‐isolated systems incorporating various GDs during strong earthquakes. Three typical types of passive GDs, that is, steel, shape memory alloy (SMA), and viscous GDs, were considered. An analytical model was developed for the inelastic two‐degree‐of‐freedom system incorporating GDs. Parametric response analyses were numerically conducted by varying the types and design parameters of GDs and the pulse period ratios of ground motions. The results demonstrate that adaptive systems with GDs exhibit superior deformation mitigation in the isolation layer during pulse‐like earthquakes, compared with conventional systems without GDs. The comparisons of various GDs indicate that steel GDs characterized by full energy dissipation are effective in decreasing the maximum force in the isolation layer and maximum deformation of the superstructure, while the insufficient self‐centering capability may increase the deformation responses and the risk of MW pounding in the isolation layer, during pulse‐like earthquakes. In contrast, SMA GDs with superelastic effect and medium energy dissipation achieve better mitigation in the maximum and residual deformations of the isolation layer, decreasing the risk of MW pounding. On average, steel and SMA GDs exhibit comparable maximum deformation and acceleration of the superstructure. Viscous GDs exhibit significantly higher maximum shear force and energy dissipation during pulse‐like ground motions. Therefore, compared with hysteretic GDs, viscous GDs may achieve superior deformation mitigation in the isolation layer, while increasing the maximum deformation and acceleration of the superstructure, during pulse‐like ground motions. Design recommendations are proposed for adaptive isolation systems incorporating various passive GDs, advancing the seismic design for mitigating MW pounding and enhancing seismic resilience.
ABSTRACT Metallic dampers have become popular in recent years, particularly for structural reinforcement, because of their rapid response and interchangeability. This study aims to investigate the effects of the Fibonacci and Lucas number sequences on the structural performance of a bolted metallic damper arranged according to these sequences, using experimental and numerical (ANSYS) analyses. Four specimens were tested under a cyclic loading protocol in ± 2.5 kN increments: one standard, equally spaced specimen (Specimen 1) and three others based on the Fibonacci and Lucas sequences (Specimens 2, 3, and 4). Experimental results showed that the damper designed according to the Lucas sequence (Specimen 3) achieved the highest cumulative energy absorption capacity in the pull direction of 476.84 J and exhibited more stable behavior than the reference specimen. Specimen 4 (Fibonacci) achieved the highest displacement under push loading (10.06 mm), making it the most effective model at increasing the system's ductility. Numerical analyses conducted using ANSYS explain the fundamental reasons for these performance differences. von Mises, shear, and normal stress analyses confirmed that the Lucas arrangement distributes stress concentrations most homogeneously across the plate (optimizing stress flow) and prevents the plastic deformation of the end bolts observed in the conventional arrangement. Plastic strain maps show that mathematical arrangements use the yield capacity of the material more efficiently. In conclusion, it has been demonstrated that bolt arrangements based on the Lucas and Fibonacci sequences significantly improve both the energy absorption capacity and the ductility of metallic dampers compared with standard methods.
ABSTRACT The seismic response of multifloor grain warehouses is affected by grain–structure interaction, whereas the application of a self‐centering configuration to heavily loaded storage structures remains limited. Refined nonlinear finite‐element models are established for a multifloor grain warehouse with a self‐centering configuration (SC) and traditional configuration (TS), with the modeling strategy benchmarked against previous experimental results. The seismic responses of the two configurations are compared under ground motions and filling conditions from empty to fully filled. The SC configuration exhibits lower natural frequencies than the TS configuration, with relative reductions of about 30%–42% in the analyzed cases. The difference in seismic response demand between the two configurations becomes more evident as stored‐grain mass increases. Under the fully filled condition, the SC configuration reduces peak floor acceleration by about 20%–27% and maximum interstory drift ratio by about 25%–35% relative to the TS configuration. Lower dynamic lateral grain pressure and overpressure coefficients are observed along the warehouse walls, particularly in shallow regions. These results indicate that the SC configuration can reduce acceleration demand, deformation demand, and dynamic lateral grain pressure response in multifloor grain warehouses, with the effect becoming more evident at higher filling levels.
The global stability of coupled shear walls under distributed axial loading remains without a closed-form solution when local wall shear deformation is simultaneously considered. Existing closed-form solutions are restricted to concentrated loads applied at the top, and existing distributed-load solutions exclude local wall shear deformation. No explicit non-iterative expression has previously been derived for the distributed-load case in any of the three generalized continuous models reported in the literature (MSB, GCTB, and GSB). This paper derives such expressions through a decomposition into independent subsystems of the sixth-order differential equation governing the behavior of each generalized continuous model. The decomposition partitions the total vertical load into two components whose associated subsystem equations are treated as uncoupled: the first is structurally identical to the classical sandwich beam subjected to distributed loading and directly recovers the reference critical load; the second takes the form of the classical sandwich beam under a concentrated top load with an effective negative load, whose analytical solution quantifies the stiffness reduction attributable to the local shear deformation of the wall. The total critical load is expressed compactly as the product of the classical critical load and a reduction factor characteristic of each model, evaluated explicitly without iteration. For the MSB and GCTB models, this factor involves the combined shear stiffness, whereas for the GSB model it depends exclusively on the local shear stiffness, reflecting the distinct kinematic coupling topology of each formulation. Validation against equivalent-frame finite element models developed in SAP2000, covering an asymmetric single-bay wall system and a three-bay configuration, confirms that, for buildings of 10 stories or more, the signed relative errors remain below the 5% threshold commonly accepted in structural engineering practice. The GSB model consistently provides the closest agreement with the finite element results. A sensitivity analysis of this reduction factor reveals a monotonic decrease with increasing coupling beam depth and an asymptotic convergence toward unity as local shear effects vanish in the high-slenderness limit. The resulting expressions are fully explicit, require the evaluation of only five dimensionless parameters per model, and constitute a practical analytical tool for the preliminary design and global stability assessment of coupled shear wall systems. The proposed method is valid for both single-bay and multi-bay configurations, though larger error margins should be expected in the latter.
This study proposes a physics-guided multi-stage deep learning (PG-MSDL) model for rapid prediction of incremental dynamic analysis (IDA) curves of prestressed concrete (PC) frames with infill walls, considering interior and exterior column removal conditions. Eighteen high-dimensional parameters, related to physical and geometric properties, including sectional dimensions and material properties of concrete, reinforcement, steel strands, and infill walls, are used as input variables. Purely data-driven models, such as XGBoost and Transformer, are first investigated, but their prediction accuracy is limited. By integrating physics-based performances and finite element results, the PG-MSDL model markedly improves the prediction of IDA curve evolution and key performance points, enhancing robustness and accuracy under highly nonlinear responses. Furthermore, a Sobol global sensitivity analysis based on the surrogate model reveals that infill wall properties dominate load-related responses, whereas displacement responses are more sensitive to structural parameter interactions. The proposed approach provides an efficient and reliable method for predicting progressive collapse behavior of PC frames under high-dimensional uncertainty.
This study presents a novel approach to optimizing column mass in complex reinforced concrete structures by integrating multiobjective optimization with variants of the K-means Optimizer (KO) algorithm. A key technical contribution of the research lies in the development of a two-way computational system that establishes a direct connection between MATLAB and ETABS via the Open Application Programming Interface (OAPI). This integration enables MATLAB to function as an independent computational platform capable of automatically updating design parameters within the finite element model (FEM) in ETABS, eliminating the need for manual interaction with the software's graphical interface. Building upon this automation framework, objective functions are formulated with constraints related to structural drift and interstory displacement. The search for a robust and efficient optimization algorithm is conducted through performance evaluations of KO variants across 50 benchmark test functions. To validate the effectiveness and practical applicability of the proposed methodology, two case studies are carried out: (1) a 15-story planar reinforced concrete frame subjected to both gravity and lateral loads and (2) a realistic 10-story three-dimensional structural system under comprehensive load combinations. The results from both cases confirm that the proposed method satisfies all structural constraints while achieving near-optimal mass reduction. Furthermore, the study introduces an enhanced variant of the KO algorithm, demonstrating strong potential for application not only in structural optimization but also in solving other complex engineering optimization problems.
Current research on dual-objective optimization designs aimed at the targeted dual-control of displacement and acceleration remains limited. This study investigates a single-degree-of-freedom (SDOF) structure with an inerter isolation system. The inerter isolation system comprises a tuned viscous mass damper (TVMD) and a rubber bearing connected in parallel, termed the TVMD-rubber isolation system (TRIS). Through comparative analysis with conventional isolation systems, a dual-objective performance control framework is proposed to simultaneously optimize the isolation displacement mitigation ratio and the absolute floor acceleration mitigation ratio. The relationship between TVMD design parameters and the dual control objectives is analyzed, revealing that for prescribed displacement and acceleration mitigation demands, minimizing the stiffness ratio of the inerter system enables the targeted control of both responses. On this basis, a multi-objective optimization approach is proposed for the inerter isolation system that incorporates targeted dual-control of displacement and acceleration responses. Numerical case studies confirm the efficacy of the proposed approach, showing that optimized inerter isolation system parameters achieve statistically targeted control of both isolation displacement and absolute floor acceleration under white noise excitation and selected ground motion. Furthermore, the effectiveness of this targeted control is proven to remain robust even when accounting for the nonlinearity of the superstructure.
Reinforced concrete (RC) columns may develop defects due to long-term material degradation or construction deficiencies such as honeycombing and voids, which substantially reduce their load-bearing performance. To address this issue, defective zone replacement using cement-based grouting material (CGM) has been proposed as an effective strengthening technique. In this study, nine axial compression tests were carried out to investigate the failure characteristics, load-displacement responses, strain distribution, and stiffness degradation of RC columns. The effects of varying defective zone replacement thicknesses and locations on the axial compression performance were experimentally evaluated, whereas numerical simulations were conducted to further examine the influence of replacement thickness, grout strength, and defective concrete strength on ductility, load-bearing capacity, and energy dissipation capacity. The results demonstrate that replacing defective concrete with CGM effectively mitigates stiffness degradation in strengthened columns during the plastic stage. Columns strengthened at the lower defective region exhibit higher recovery efficiency in axial load-bearing capacity compared to those strengthened at the midheight defective region. Among the parameters investigated, CGM replacement thickness is identified as the most significant factor influencing strengthening effectiveness. As the replacement thickness increases, the axial compressive bearing capacity and energy dissipation capacity of the strengthened columns improve by approximately 39.9% and 74.8%, respectively, whereas ductility decreases by about 11.3%. Furthermore, after strengthening, the region of high-stress concentration shifts from the defective zone to the intact concrete zone. It is recommended that the strength of the grouting material should not exceed 2.5 times that of the original concrete, and the cross-sectional replacement ratio should be limited to no more than 90%. Based on both experimental and numerical findings, a calculation method for the axial compressive bearing capacity of RC short columns is proposed, incorporating the lateral confinement effect of the outer grouting material on the defective concrete. The predicted results show good agreement with the experimental data.
To enhance the ductility and energy-dissipation capacity of traditional steel frame-tube structures, high-strength steel frame-tube structures with splice-plate bolted shear links (HSS-FTS-SBSLs) were proposed. HSS-FTS-SBSL combines the advantages of replaceable shear links and steel frame-tube structures, providing good cyclic hysteretic behavior and energy-dissipation capacity under cyclic loading. In this study, the software ABAQUS was used to create finite element (FE) models of 15 full-scale single-story single-span HSS-FTS-SBSL substructures. The hysteretic behaviors, bearing capacity, stiffness, energy dissipation, and plastic deformation capacity of FE models were evaluated. FE analysis results showed that changing the length ratio of the shear links significantly affects the bearing capacity, stiffness, and energy dissipation of the FE models. When the shear-link length ratio is reduced from 1.45 to 0.73, the load-carrying capacity of the HSS-FTS-SBSL increases by 23.9%, the initial stiffness increases by 19.1%, and the energy-dissipation capacity increases by 28.8%. Based on the FE analysis results of this study, it is suggested that as the length of the shear link increases, the contribution of the connection between the splice plate and bolts to the structural rotation significantly increases, thereby reducing the plastic rotation of the shear link. It is recommended that the length of the splice-plate bolted shear link in the HSS-FTS-SBSL should not exceed 1.13. Without stiffeners, the bearing capacity and energy dissipation of the structure could be reduced. The spacing of the link web stiffeners had little effect on the bearing capacity, stiffness, and energy dissipation of the structure. When the web stiffener spacing is reduced from 2e/3 to e/5, the load-carrying capacity of the HSS-FTS-SBSL increases by less than 5%, whereas the initial stiffness and energy-dissipation capacity increase by less than 3%. Based on this analysis, it is recommended that the spacing of the link web stiffeners in HSS-FTS-SBSL should be between e/4 and e/3 (where e is the length of the shear links), following the requirements of the design code. The splice-plate thickness and bolt diameter had no effect on the bearing capacity, stiffness, or energy dissipation of the structure. Increasing the splice-plate thickness by 40% and the bolt diameter by 20% improves all HSS-FTS-SBSL performance indices by less than 2% and 1%, respectively.
Seismic engineering is facing challenges related to natural disasters, particularly earthquakes. The base isolation has been a proven vibration control technique for tall buildings, effectively reducing the impact of earthquakes on structural systems. Lead rubber bearings (LRBs) are a common implementation of this technique. This paper presents a detailed evaluation of the LRBs applied to an actual building. The LRBs' selection process and parameter determination are based on the building's specific features, ensuring compatibility between the isolator and structural requirements. The building is modeled using the finite element method, with the LRBs simulated as nonlinear base-isolator elements for precise performance assessment. Two earthquake records (i.e., El Centro and Chi-Chi) are used to analyze vibration control effectiveness under seismic loads. This paper examines two aspects: (1) the overall structural responses, including vibration responses, seismic energy absorption, peak displacement, story drift, peak acceleration, and base shear force; and (2) the internal forces in members, including shear forces and bending moments in columns and shear walls. Comparing results with and without the LRBs, under both normal conditions and seismic events, highlights their significant benefits. The findings serve as a comprehensive guide for structural engineers in choosing optimal vibration control strategies for tall building structures.
Shape memory alloys (SMAs) have attracted increasing attention in recent years for their application in self-centering (SC) seismic structures. To take full advantage of their recovery capability and energy dissipation (ED) potential, SMAs are typically incorporated into plastic hinge regions of reinforced concrete components as longitudinal reinforcement or utilized in high-performance seismic protection devices. However, for widely used nickel-titanium SMAs, their smooth surface and poor machinability present significant challenges for the design of reliable mechanical connections with conventional steel reinforcement. To address this issue, this study proposes an efficient SMA-steel bar connection strategy that integrates swaged sleeves on SMA bars with straight-threaded couplers, enabling reliable force transfer and rapid specimen assembly. The structural configuration and key design considerations of the proposed connection system were first presented. Experimental investigations were then conducted to evaluate its mechanical performance, with particular emphasis on the effects of sleeve length and bar diameter. Test results demonstrate that the proposed connection system provides a stable mechanical splice and reliable load transfer under various loading conditions, while maintaining the characteristic flag-shaped hysteretic response of SMAs. Although the ED capacity of SMAs is lower than that of conventional hysteretic dampers, their primary function is to provide substantial SC capability to structural systems, which makes them highly attractive for seismic design. This study provides an efficient and reliable connection solution for SMA bars, supporting their wide application in seismic-resilient structural systems.
This study proposes a multiobjective evolutionary algorithm based on objective conversion (MOEA/OC) for braced steel frame structure optimization. The algorithm innovatively integrates three mechanisms. A dynamic interval division strategy is employed to decompose the multiobjective problem into subproblems with adaptive constraints, eliminating the traditional reliance on dominance relationships. This strategy, combined with an archive-guided differential evolution operator, enables mutation and crossover operations driven by elite solutions, preserving diversity in the offspring while enhancing algorithm convergence. Benchmark tests were conducted, and the algorithm was compared with the nondominated sorting genetic algorithm II and the multiobjective evolutionary algorithm based on decomposition, demonstrating superior robustness and convergence. In a six-story frame example, the MOEA/OC algorithm outperforms the other two algorithms in terms of speed in finding Pareto optimal solutions. For the 12-story braced steel frame case, the structure designed using MOEA/OC achieves a cost saving of 43%, with inter-story drift angles controlled between 0.0029 and 0.0128, balancing economy and performance and demonstrating the potential of MOEA/OC in complex structural optimization. Additionally, the frequency distribution of braces in each bay of the steel frame layout on the Pareto-optimal solutions was analyzed using statistical counting methods, providing data-driven design recommendations for designers.
This study conducts a probabilistic seismic assessment of steel diagrid high-rise structures with vertical irregularities, evaluating 18- and 24-story configurations-including fully regular (Model A), fully stepped-back irregular (Model B), and hybrid stepped-back layouts (Model C)-under near-fault ground motions. Finite element models, designed according to the Iranian National Building Code (INBC) and Standard No. 2800, were analyzed using Incremental Dynamic Analysis (IDA). Key metrics such as interstory drift and stiffness degradation were tracked to characterize nonlinear behavior, with lognormal fragility curves calibrated via maximum likelihood estimation (MLE). Results reveal that building height and plan irregularities critically influence seismic performance: regular 24-story configurations demonstrated 15%-20% lower drift responses and higher collapse capacities than irregular counterparts, while 18-story structures exhibited superior dynamic resilience. Notably, slab removal and setbacks amplified vulnerability under high-intensity shaking. These findings underscore the necessity of maintaining diagrid continuity at setbacks and redistributing lateral stiffness to enhance seismic resilience in irregular high-rise systems.
With the proposal of the probabilistic framework for performance-based earthquake engineering, seismic fragility analysis has attracted widespread attention. It quantitatively evaluates the seismic performance of structures from a probabilistic perspective and macroscopically reflects the relationship between ground motions effects and the degree of structural damage. With the rapid economic development and accelerated urbanization process, the number of high-rise structures has been increasing steadily. Given the uncontrollable consequences of seismic damage to high-rise structures, conducting seismic fragility analysis on these structures carries significant engineering value. In this study, with reference to the division of performance levels and the determination of quantitative indicators specified in Chinese National Standards and Chinese Association Standards, the limit states of high-rise structures under ground motion are classified into five levels. The software SAUSAGE is employed to establish nonlinear dynamic analysis models for a 141.3-m-high shear wall structure and a 199.7-m-high frame-core wall structure. After fully accounting for the uncertainty of ground motions, probabilistic seismic demand analysis and seismic fragility analysis based on the cloud method are conducted on the high-rise structures. The probabilities of the high-rise structures exceeding the five limit states under three seismic levels corresponding to different seismic fortification intensities are obtained. The results indicate that (a) the probabilistic seismic demand analysis and seismic fragility analysis based on the cloud method can provide a robust scientific basis for the seismic performance evaluation of high-rise structures and that (b) high-rise structures designed in accordance with Chinese national standards can meet the three-level seismic fortification objectives of "no damage under frequent earthquake, repairable under fortification intensity earthquake, and no collapse under rare earthquake."
Seismic-induced vibrations are harmful to high-rise buildings. This study proposes the polymer damping multilayer anisotropic displacement amplified system (PDMADAS) as an effective method for mitigating these vibrations. The motion equations for single-layer displacement amplified damper (SDAD), multilayer displacement amplified damper (MDAD), and multilayer anisotropic displacement amplified damper (MADAD) are derived. The multilayer anisotropic displacement amplified characteristics of MADAD are analyzed, and the control principle of the damping system is explained. Four damper prototypes are designed and manufactured, and their damping force and energy dissipation are evaluated through a series of mechanical performance tests. Additionally, the influence of PDMADAS on structural response control is investigated using the displacement amplification damper installed in the polymer damping system. Compared with VD, the amplification factors for the maximum damping force and energy consumption of MADAD are 12.09 and 10.64 times, respectively. The results show that combining the polymeric damping system with MADAD is more effective in reducing seismic response.
