In order to reasonably represent the fully non-stationarity and randomness of the land acquisition seismic process, a random seismic model based on a combination of phase difference spectrum and power spectrum has been developed. Firstly, the relationship between phase difference and non-stationarity of seismic ground motion was elucidated, and the identification and statistical analysis of phase difference spectrum model parameters were carried out using strong motion records. Secondly, power spectrum models with deterministic and stochastic parameters were used to obtain the values of deterministic parameters and the normalized optimal probability distribution of stochastic parameters, respectively. Finally, by selecting representative point sets of basic random parameters, the corresponding representative time history set of seismic acceleration was obtained. The calculation example shows that the method in this paper only requires 2 or 4 basic random variables to simulate the seismic acceleration process with natural variability and rich probability information, and the simulated acceleration response spectrum fits well with the strong motion records. The study lays the foundation for applying probability density evolution theory to the random seismic response and seismic reliability refinement analysis of complex engineering structures.

There is a significant difference between the spatial distribution of ground motion along cross-fault regional areas (Ground motion in the area of the extreme proximity to the fault where the cross-fault engineering structures are located, referred to as cross-fault ground motion) and near-site ground motion. The lack of records on cross-fault ground motion poses challenges to studying the seismic resistance of cross-fault structures. This paper aims to outline the basic theory of the broadband hybrid method for simulating ground motion, and examines the distribution pattern of cross-fault ground motion using the Zemu River fault as a case study. The results indicate that the simulated cross-fault ground motion aligns with the fault sliding mode, displaying significant directional, up-disk effect, and slip-impact effect. Generally, the intensity of the simulated cross-fault ground motion follows a certain attenuation law. However, it is influenced by fault rupture, which can result in irregularities or even a counter-law phenomenon. Furthermore, the actual location of surface rupture and the zone of large slip along the fault have a substantial impact on the distribution pattern of cross-fault ground motion. By employing the broadband hybrid method, artificial cross-fault ground vibration time series can be generated to address the lack of recorded cross-fault ground motion. This methodology provides substantial support for research on the seismic resistance of cross-fault structures.

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.

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.

In order to analyze the trend and significance of the influence of different factors on the seismic performance of flexible connection autoclaved areated concrete(AAC) masonry filled wall steel frame structures, the feasibility of the modeling method and parameters selection was verified based on the results of pseudo-static tests, nine orthogonal finite element models were established by ABAQUS, and variable parameter analysis was carried out on axial compression ratio, reserved seam width, spring stiffness and height span ratio of models. The results show that the effects of reserved joint width, stiffness of energy-consuming materials, height span ratio and axial compression ratio on seismic performance of the structure decrease successively. On the whole, it is beneficial to increase the reserved joint width, reduce the stiffness of energy-consuming materials, high span ratio and axial compression ratio to improve the seismic performance of the structure. In actual application, the recommended value for the joint width between flexible connection AAC wall and frames is around 40 mm, and the stiffness of the filler between reserved joints is between 100~500 N/mm.

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.

Infilled reinforced concrete (RC) frame structures are one of the most common structures. It is found that infilled walls have a significant impact on seismic performance of RC frames in past earthquake damage investigations and experimental tests. To accurately and rapidly assess seismic damage states of infilled RC frames after an earthquake, 660 infilled RC frames were firstly designed based on different building structure information (i.e. the seismic design intensity, constructed period, number of stories, story height, number of bays and the filling rate), then the non-linear time history analysis was performed for the 660 infilled RC frames with 10 ground motions in OpenSees. 6 600 data points were gained from the analysis, resulting in a dataset which was used to develop seismic damage state assessment models of infilled RC frames. Based on the dataset, nine machine learning models predicting seismic damage states of infilled RC frames were developed using naive Bayes (NB), K-nearest neighbors (KNN), decision tree (DT), artificial neural network (ANN), random forest (RF), adaptive boosting (AdaBoost), extreme gradient boosting (XGBoost), light gradient boosting machine ( LightGBM), category boosting (CatBoost) algorithms. The results indicated that CatBoost and RF models had the highest prediction accuracy for the seismic damage state which was 0.93 in testing dataset, followed by LightGBM and XGBoost models with an accuracy of exceeding 0.90. Compared with actual damage investigated in the past earthquakes indicating that RF and CatBoost models achieved an identical accuracy of 47%. However, the difference in the remain damage states within one damage state level occupied 76% for CatBoost model, which was higher than that of RF model. Based on the CatBoost, importance analysis was performed for different input variables. It is found that three input variables had the greatest impact on infilled RC frame, including seismic design intensity (SDI), peak ground velocity (PGV) and the spectral acceleration at S_a(0.4 s). Furthermore, the importance of the number of stories on the seismic damage state for infilled RC frames increased as the increase of the number of stories.

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.

In order to investigate the seismic performance of the suspended structure with viscous damper during earthquakes, the shaking table tests were carried out on two 1/20 scaled models of suspended structures, which were equipped with rigid rods and viscous dampers respectively. The dynamic characteristics, damping ratio, structural response and damping effect of model structures were researched. The test results show that compared with the common suspended model structure, the natural frequency of the suspension damping model structure is reduced, while the damping ratio is improved, especially the first frequency and the corresponding damping ratio. The peak accelerations of the top of the main structure and the fifth suspended-floor of the suspension damping model structure are less than those of the common suspended model structure, but the damping amplitude of the peak acceleration of the fifth suspended-floor is even up to 94.34%. The maximum displacement of the top of the main structure is also distinctly smaller than that of the common suspended model structure. Different seismic wave input has different damping effect, in which the effect of Taft wave is the best, the El Centro wave is the second, and the last is artificial wave. However, the maximum relative displacement between the main structure and the suspended-floor is greater than that of the common suspended model structure, which shows that the stronger the connection between the main and secondary structures, the smaller the relative displacement. It also indicates that the suspension damping model structure takes advantage of the swing of the suspended-floors and the viscous dampers to consume energy, so that the suspended structure with viscous dampers has better effect of energy dissipation and vibration reduction.

Traditional partially encased composite(PEC) beams usually adopt straight web plates, however, such web plates exhibit lower shear carrying capacity and lack mechanical interlock with concrete, which hinders their collaborative performance. To address the adverse effects of straight web plates, this study proposes the utilization of corrugated web plates as a cross-sectional replacement, leading to a novel corrugated web PEC beam. Through low-cycle repeated loading tests, the seismic ductility performance of the corrugated web plate PEC beam under earthquake loads was analyzed. The influence of flange thickness and shear-span ratio on the load-bearing capacity, failure mode, deformation capacity, hysteresis energy dissipation capacity, and stiffness degradation of the sinusoidal corrugated web PEC beam were investigated. The research demonstrated that a properly designed corrugated web plate PEC beam exhibited favorable load-bearing capacity and seismic ductility performance. The shear-span ratio significantly affects the failure mode and ductility of the beam, while increase the flange thickness effectively and enhances the load-bearing capacity of section. However, excessively thick flanges can impact the collaborative performance between the steel section and concrete. In this experiment, specimens with smaller flange thickness and larger shear-span ratios demonstrated high compatibility between the steel section and concrete, resulting in full utilization of their ductility and energy dissipation capacity.