In order to solve the problems of low out-of-plane stiffness of the energy dissipation web of traditional shear plate damper and easy to occur out-of-plane buckling under large deformation, a sinusoidal waveform steel plate damper was proposed. Considering the placement direction of the waveform web and the yield strength, four specimens were designed and tested under low cycle repetitive load to analyze the hysteretic performance, bearing capacity and stiffness degradation. The results show that strong energy dissipation capacity, good ductility, and stable hysteresis performance under large deformation is the characteristics of sinusoidal wave plate damper, and the transverse wave steel plate damper with low peak load is the best. The energy dissipation capacity and ductility are better than those of the vertical waveform steel plate damper, and its stiffness degradation rate is higher than that of the transverse waveform steel plate damper. The hysteretic curve of webs made of low yield point steel is full.

For super high-rise shear wall structures with large stiffness and small inter-story displacements, the viscous dampers are arranged in the refuge floors using toggle-brace-dampers , and there are still deficiencies in the value of the amplification coefficient and the arrangement. The toggle-brace-damper is a displacement amplification device, which improves the energy dissipation capacity of the damper by amplifying the axial travel of the damper. From the perspective of geometric analysis, the structural of the reverse toggle-brace-damper vibration mitigation efficiency and arrangement optimization are explored: The analytical equation for the maximum displacement of the damper axis of the reversed device is derived, and the dynamic response of the structure under the device with different arrangement heights and different amplification factors is compared. When the arranged frame span is too large, the dynamic response of the structure before and after the setup is compared by setting up the device of the overhanging truss. The results show that the efficiency of the toggle-brace-dampers system is related to the height and span of the arranged frame, and the theoretical amplification coefficient determined according to the angle is not proportional to the vibration mitigation efficiency of the structure. The structural vibration mitigation efficiency is higher after the optimized arrangement than the original arrangement. The optimized scheme has been verified in actual projects, i.e., a reasonable selection of the amplification factor and arrangement can improve the additional damping ratio of the structure to a greater extent.

Aim at the complexity of response analysis methods for energy dissipation systems composed of series-parallel layout II inerter dampers (SPID-IIs) in high-rise structures under random excitation, closed-form solutions for structural displacements and damping force response of SPID-IIs are proposed. Based on the proposed solutions, the influence of real mode number on analysis accuracy was studied, and the feasibility of the layout strategy of SPID-IIs installed on floors with interlayer displacement exceeding the limit of the main structure was explored. Firstly, based on the mechanical construction diagram of SPID-II and its setting method between adjacent floors in structures, a differential constitutive relationship between the damper damping force of SPID-II and the horizontal displacement of structural nodes was established, and the coupled seismic motion equation of the high-rise building and SPID-II was reconstructed. Secondly, the real mode decoupling method is used to obtain the concise equivalent dynamic parameters of high-rise structures, and the power spectrum quadratic decomposition method is applied to energy dissipation systems to derive the accurate quadratic solutions of the power spectrum of a series of responses such as the absolute displacement of high-rise structure nodes relative to the ground, interlayer displacements of vertical components of the high-rise structure and damping force of SPID-IIs. Then, a concise closed-form solutions of the 0-2nd order spectral moments of those design parameters of the energy dissipation system subjected to random seismic excitation modelled by double filtered white noise were derived. Finally, the correctness of the method proposed in this paper was verified through numerical examples, and the influence of the number of real mode shapes on the accuracy of energy dissipation system design parameter analysis was studied, as well as the influence of the position of inertial dampers on the seismic reduction effect. Results shows that for the response analysis of multi-degree of freedom energy dissipation structures, it is recommended to use the number of vibration modes corresponding to the cumulative mass participation coefficient reaching 100% in the original structural free vibration analysis, which can achieve stable accuracy and improve the analysis efficiency of energy dissipation systems with SPID-IIs installed in large and complex high-rise structures. The proposed strategy for setting SPID-IIs with appropriate mechanical parameters can effectively reduce the seismic response of high-rise structures by placing a SPID-II in the floor where interlayer displacement of the original structure exceeds the limit or in the middle floor between three adjacent floors where interlayer displacements of the original structure exceed the limit. The proposed closed-form solutions method and the layout strategy of SPID-IIs in high-rise building can provide useful reference value for the practical engineering application of SPID-IIs.

The braking behavior of trains will notably affect the longitudinal movement of suspension bridges. Therefore, it becomes imperative to delve into the longitudinal movement of kilometer-level railway suspension bridges under the influence of train braking. This study takes a long-span railway suspension bridge with a main span of 1060 meters as its research object, and explores the response characteristics of its longitudinal movement at the girder end when subjected to train braking forces and the controlling effect of a fluid viscous dampers (FVDs) by numerical simulation. Firstly, the engineering background of the kilometer-level railway suspension bridge and the finite element model established using ANSYS software are introduced. Then, the loading and solution methods for the longitudinal movement of the long-span railway suspension bridge, the finite element simulation methods for bearing friction and FVDs, and the simulation method for braking force are described. Subsequently, the effects of different braking positions and consideration of bearing friction on the longitudinal movement response of the suspension bridge are investigated. Finally, the control effect of FVDs on longitudinal movement is studied, and parameter analysis is conducted. The results show that as the braking position approaches the point where the train exits the bridge, the shape of the longitudinal displacement curve becomes more similar to a sine function. Bearing friction has a certain control effect on the displacement response at the girder end under train braking, but its control effect on the velocity response is not ideal. The utilization of FVDs effectively controls both displacement and velocity responses at the girder end of the suspension bridge under train braking. The optimal control effect is achieved when using a FVD with a damping coefficient of 2500 kN•(m/s)^-α and a velocity exponent of 0.1.

By combining the partial self-centering shape memory alloy(SMA) braces (SCB) with the shear slotted bolted connection-very short shear link (SSBC-VSSL), an innovative self-centering shear link (SC-SL) used in the eccentrically braced frame (EBFs) that has an advantage of good energy dissipation capacity and self-centering capacity, low damage and excellent seismic resilience capacity is developed. Cyclic tests were carried on SC-SL specimens designed by the proposed method, so the deformation modes and hysteresis curves can be obtained. Based on the test results, ten SC-SL models with the effect of SMA areas, high-strength bolt pretensions and shim friction coefficients were designed and analyzed by the validated finite analysis (FE) method. The results show that the VSSL is in the relative static during the slip stage, then the development process of very short shear link (VSSL) in SSCB-VSSL including yield, bearing, energy dissipation and inelastic deformation are appeared sequentially during the non-slip stage, while the SMAs in SCB are always subjected to elongation, thus increasing the energy dissipating capacity and self-centering capacity. Finally, the simplified mechanical models of SC-SL in the slip stage and non-slip stage are proposed by using the FE results, which can provide a new way to give important seismic design reference for EBFs.

In order to study the mechanism of pile-soil-structure dynamic interaction and analyze its influencing factors, the horizontal dynamic response laws of pile-soil-structure system under different superstructure mass, different input wave frequency and acceleration peak input are analyzed and discussed by using the method of shaking table test and numerical simulation analysis. The soil model of the test foundation is medium hard soil, and the shear speed is about 213 m/s. The pile group foundation is composed of five foundation piles with a length of 1.35 m and a diameter of 0.1 m arranged in cross shape. The superstructure model is simulated by mass block. The experimental results show that the bending moment and shear force of pile body are the largest at the pile-bearing joint, and decrease with increasing depth. With the increase of the superstructure mass, the acceleration reaction between soil and pile foundation increases significantly, and the bending moment and shear force of the pile body also show an increasing trend. With the increase of the input sine wave amplitude and frequency, the motion interaction becomes larger, and the bending moment and shear force in the pile body become larger. The change of superstructure quality has the greatest impact on the dynamic interaction of the pile-soil-structure system, followed by amplitude and frequency.

Underground rail transit is the lifeline of urban transportation. Due to the frequent occurrence of earthquakes and the increasing frequency of train entry and exit in China, the structure of subway stations is susceptible to both seismic and train loads. However, the current research on the seismic performance of subway station structures has not considered the practical problem of seismic and train load coupling. In order to ensure the safety of subway station structure when the seismic struck as the train was entering and leaving the station occur, a three-dimensional refined calculation model of soil, subway station and track interaction is established. The load form of train braking entering the station is selected to apply on the track surface, and the three-dimensional seismic wave is input at the bottom of the model. The variation law of stress, displacement and acceleration of subway station structure under the two working conditions of seismic action and seismic train coupling action is compared and analyzed. The results show that under the coupling effect of seismic and train, the peak stress at the bottom of the lower column is the highest, which is the weakest position of the station structure. After deformation occurs, the maximum yield stress value is first reached and plastic failure occurs. In the early stage of train arrival (0~5 s), the acceleration and displacement amplitudes of the board under seismic train coupling are greater than those under seismic action. In the later stage of train arrival, the acceleration and displacement of the board under both working conditions are basically the same. Under the coupling effect of seismic and train, when the seismic acceleration is small and the train speed is high, resonance occurs when the vibration frequencies of the two are close, leading to the amplification of the vibration of the plate.

Seismic(vibration) isolation technology is an effective measure to improve the seismic performance and comfort of over-tracking buildings, and the design methods optimization of such structures has practical significance and urgency. This study proposes an evaluation model based on the ratio of benefit to life cycle cost that suitable for over-tracking seismic (vibration) isolation structures. The effects of key structural parameters such as period ratio, mass ratio, stiffness and damping of the isolation layer on the benefits of the over-tracking seismic (vibration) isolation structures were studied. Based on genetic algorithms, an optimal design method for over-tracking seismic (vibration) isolation structures is proposed. The research results show that the seismic losses of the structure after adding isolation layers are mainly concentrated in the substructure, and the greater the mass ratio of the upper and lower structures, the smaller the seismic losses. The period ratio of the upper and lower structures has a greater impact on the overall seismic losses of the structure. The larger the period ratio, the smaller the seismic losses. The stiffness of the isolation layer is positively correlated with the isolation efficiency. After using the optimization algorithm to optimize the prototype structure, both seismic losses and vertical acceleration vibration levels were reduced, verifying the feasibility of this method and providing reference for engineering design.

In the accelerated process of urbanization, the deterioration of aging buildings, and the rapid climate change in current times, the resilience and sustainability of buildings have become increasingly important. Post-earthquake rehabilitation of buildings often requires significant economic and downtime cost, while also causing severe environmental impacts such as carbon emission. However, it is still lack of reasonable and rapid assessment method for evaluating seismic environmental impact. Therefore, this study proposes an improved building life cycle seismic environmental impact assessment method, using the input-output database and the “ repair cost-ratio”assumption to convert existing seismic economic loss data into environmental impacts, considering the key factors that reduce the feasibility of building rehabilitation due to residual deformation. It quantifies the life cycle seismic environmental impact of buildings under seismic risk through seismic hazard analysis, structural analysis, damage analysis, and loss analysis. Based on this method, the life-cycle seismic environmental impact assessment of steel frame buildings strengthened by self-centering braces (SCB) and buckling-restrained braces (BRB) was carried out. The results show that if the reduction in rehabilitation feasibility caused by residual deformation is not considered, the seismic environmental impact will be seriously underestimated. After considering the residual deformation, compared with BRB, the frame strengthened by SCB shows a significant advantage in reducing the impact of the seismic environment with the minimal residual deformation.

In order to quantitatively assess the effect of different infill wall construction methods on the seismic performance of reinforced concrete(RC) frames, domestic and foreign pseudo static test data of masonry infilled RC frames were collected, and a total of 68 specimens with detailed data in 19 literatures were selected as samples to analyze and compare the effects of three types of construction methods, namely, flexible connection of infill walls, integrity enhancement of infill walls, and installation of damping devices, on the strength, initial stiffness, ductility factor and equivalent viscous damping factors of the specimens. The results show that compared with the traditional construction methods, the strength and stiffness of specimens with flexible connection infill walls decrease, and the deformation capacity increases. The method of enhancing integrity can improve the strength, stiffness and deformation capacity, and it is a better method to reinforce the infill walls of existing buildings. The strength and stiffness of the structure with damping energy dissipation devices are reduced, but the deformation and energy dissipation capacity of the structure are improved, which can be used as a resilience improvement for new buildings if the construction cost is acceptable.