Abstract:Base-suspended pendulum isolation （BSPI） structure is a new type of suspension isolated structural system. Firstly， the configuration of the suspension isolation layer and mechanical model of the BSPI structure are described. Then， the finite element modeling of BSPI structure is verified through comparing with the shaking table test. Finally， the finite element models of the BSPI structure and conventional frame structure are built， and dynamic structural responses of these models are analyzed by performing time-history analysis under different seismic actions. Research results indicate that the lateral stiffness of the BSPI structure is reduced greatly by installing the suspension layer， and the acceleration response of BSPI structure is significantly reduced under rare earthquakes， which is only 1/5~1/2 of that of a conventional frame. The displacement response of BSPI structure can be effectively controlled by dampers， and it is reduced to 50% of that of uncontrolled BSPI structure under rare earthquakes. The interlayer displacement of the upper structure of controlled BSPI structure is less than 1/100， which meets the seismic fortification goal.

Abstract:To study the dynamic response law of large diameter variable cross-section single pile in liquefaction sites under different ground motion intensities， shaking table tests were conducted. Employing the 5010 wave and subjecting the system to ground motion strengths ranging from 0.10g to 0.45g， this study examined the evolution of sand pore pressure ratio， horizontal displacement at the top of the piles， bending moment along the pile body， as well as the time history response of pile acceleration and foundation damage. The test results show that the pore pressure ratio of saturated sand increases obviously with the increase of ground motion strength. The pore pressure ratio of saturated sand increases obviously with the increase of ground motion intensity. When the ground motion intensity is ≥0.30g， the stable value of the pore pressure ratio of saturated sand is near 0.9， and the sand is completely liquefied. Under the action of 0.45g ground motion， the acceleration of pile body， the horizontal displacement of pile top and the bending moment of pile body all reach the maximum. The peak acceleration at different positions along the pile body lags behind that of the input seismic wave， and the acceleration response of the pile top and variable cross-section is weaker than that of the pile tip. The maximum bending moment of the pile appears at the boundary between the liquefied soil layer and the non-liquefied soil layer， and the bending moment at variable cross-section is smaller than that at the soil layer interface. When the ground motion strength reaches 0.30g， the damage of a large diameter variable cross-section single pile occurs. Therefore， in the seismic design of the single pile foundation of a large diameter variable cross-section bridge under a liquefaction site， the bending capacity at the boundary of the saturated sand layer and variable section should be considered to ensure that the strength of the single pile meets the anti-seismic requirements.

Abstract:To investigate the dynamic response and load transfer path of the isolated structure subjected to multi-direction coupled dynamic excitation， a 1∶4 scale model shaking table test of a three-story irregular plane RC frame isolated structure was conducted.The progressive collapse resistance under multi-direction coupled dynamic excitation was revealed by studying the acceleration response， displacement response， internal force response of the isolation bearing， and concrete and reinforcement strains of the damaged span beam of the structure.Then， the distribution laws of the internal force of the damaged span beam and the damage index of the isolated bearing were analyzed by OpenSees.The results show that under the coupled excitation of the vertical unbalanced load caused by sudden failure of a single isolated bearing and bidirectional horizontal earthquake， the vertical dynamic response at the failure point increases significantly， and the markedvertical deformation occurs.The dynamic effect caused by isolated bearing transient failure has an influence on the internal force of all remaining bearings.In particular，the impact on the neighboring bearing’s internal force is more visible.Vierendeel action and beam end bending moment resist the vertical unbalanced load generated by isolated bearing transient failure.The damage index of neighboring bearings is most affected by the isolated bearing transient failure. The dynamic response of the failure zone under the multi-directional dynamic coupling excitation is more pronounced than that under the vertical unbalanced load only， and the damage index distribution of the isolation layer is more discrete than that under earthquakes only.

Abstract:In order to study the seismic response law of the subway station structure with integrated superstructure，based on the above ground underground integrated structure system of rail transit and single subway station structure system，the shaking table test of silty sand was carried out. The seismic response of subway station structure is studied from the acceleration and strain，and the results are compared with each other. The results show that: 1) with the increase of seismic intensity，the acceleration peak of soil and the structure increases gradually，while the acceleration amplification coefficient decreases gradually. The variation law of acceleration along the buried depth is related to the type of ground motion; 2) with the increase of seismic intensity，the amplitude of tensile strain of the integrated superstructure gradually increases. In the model，the amplitude of tensile strain at the end of the column is the largest，followed by the side wall，and the floor shows the smallest value. 3) The acceleration and strain of the integrated subway station structure are smaller than that of the single subway station structure，while the acceleration variation law is similar. With the increase of seismic intensity，the difference of strain amplitude gradually increases，while the difference increase show the gradual decrease and converge trend.

Abstract:To study the seismic response characteristics of the seamless transfer subway station and improve the understanding of the seismic performances of such station structures, the shaking table test on a scale model of such station structure was carried out for the first time. The design of the shaking table test included the preparation of test models, the arrangement of measuring points, collection of testing data and the design of test working conditions. Then, the processes of the model test were simulated by three-dimensional finite element method. Through comparison between the numerical and measured results, acceleration responses of the model soil, strain and internal force responses of the structure model and soil pressure responses on the sidewall were analyzed. The results showed that the numerical results agreed well with the test data, which validated the rationality of the modeling method in this paper. For the structure model of the seamless exchange subway station, the structural exchange end had an obvious influence on the structural deformation, the structural internal force and its surrounding soils. When the distance between the station exchange ends exceeded 1.5 times station structural width, its effect basically disappeared. These conclusions can provide powerful support to the three-dimensional calculation method for the seismic analysis of complex subway stations and the anti-seismic design of such station structures.

Abstract:In order to investigate the influence of different structural parameters on the seismic performance of low-rise lightweight steel buildings，the finite element model of lightweight steel building was established by ABAQUS based on the experimental results. It shows that the finite element analysis results，in terms of fundamental frequency，acceleration and displacement responses，agree well with the experimental results. Furthermore，a parametric study based on the verified model under 9-degree frequent occurring and maximum considered earthquakes was carried out. The results show that the increase of the sheathing number and adding diagonal bracing can improve the fundamental frequency，acceleration and displacement responses of buildings，but the change of the sheathing material has little effect on it; the wall opening ratio has obvious effect on the structural response of the building under earthquake. Thus，the wall opening ratio should not be greater than 29.09%; decreasing the aspect ratio and choosing regular plan layout of lightweight steel buildings result in the increase of the natural frequency and decrease of the acceleration response and displacement response.

Abstract:The seismic performance and failure mechanisms of the substation structure system considering dynamic interaction on the main structure and substructure was studied systematically, based on the mechanism of primary-secondary structure dynamic interaction, implicit dynamics numerical simulation analysis and shaking table test. Seismic response of the structure system was analyzed in some aspects such as internal force, displacement and acceleration. This paper obtained the interaction mechanism between the electrical equipment with main structure, the dynamic magnification factor of the electrical equipment and the dynamic property values, and put forward the seismic performance goals of the main structure. Meanwhile, the results based on the displacement revised factor method established the level damage assessment model and the overall damage assessment model, and then proved the correctness of the damage assessment model by shaking table test. These research results have important reference function on seismic design and seismic damage assessment of the similar lifeline engineering and industrial architectures with complex equipment.

Abstract:To solve the problem of seldom use of isolation technology in super high-rise buildings as well as the restriction on the tensile capacity of isolation bearing and structural height-width ratio limitation，in this paper，the combined isolation layers consisting of lead rubber bearings and elastic sliding bearings were set at the bottom of the sub-structures in the new mega-sub structure system. An experimental model of mega-sub structure was designed and manufactured，which included three mega floors. Shaking table tests of the uncontrolled and controlled mega-sub structure under near-fault and far-fault ground motions were carried out. Vibration control effects of combined isolation layers on the seismic vibrations of main-structure and sub-structures and the influences of near-fault ground motions were studied. The results show that the combined isolation layer at the bottom of sub-structure is equivalent to a tuned mass damper for the main-structure，and it has obvious damping effect of TMD on the seismic reactions of main structure，while it is equal to a base isolation structure for the sub-structure itself，and it has significant isolation effect on the seismic responses of sub-structure. Seismic reactions of the main-structure and the sub-structures under near-fault ground motions are larger than that under far-fault ground motions due to the pulse effect.

Abstract:In order to investigate the vibration mitigation performance of the Tuned Liquid- Particle Damper (TL-PD) during earthquakes，a series of shaking table tests were conducted on a steel frame structure with different damping devices，including Tuned Liquid Damper (TLD)，Particle Damper (PD)，and TL-PD.During the testing，three ground motions were adopted as excitation inputs.Testing results show that the TL-PD has a good vibration suppression effect.The root-mean-square values of displacement and acceleration responses of the structure can be reduced by 63.2% and 50.5% at most，respectively.The TL-PD also shows a better robustness than that of the TLD，although the performance of the TL-PD is still influenced by the ground motion characteristics.Additionally，the TL-PD produced less noise than that of the PD in the tests.Based on empirical model，a mathematical model was developed to capture the behaviors of TL-PD in the preliminary design.

Abstract:In order to investigate the effects of MR dampers on vibration mitigation and dynamic reliability of structures，shaking table tests on the structures with and without MR dampers subjected to random earthquake ground motions were carried out.The reliability assessments of the controlled and uncontrolled structures were respectively performed using the extreme value distribution theory and the probability density evolution method.In the shaking table tests，representative time histories of ground accelerations were generated by employing a physical stochastic ground motion model.Experimental and analytical results reveal that the mean and standard deviation of inter-story drifts of the structure with MR dampers are significantly less than those in the uncontrolled cases，respectively，and the absolute accelerations of most floors are reduced to some extent；the variability in dynamic responses of the controlled and uncontrolled structures subjected to random earthquake ground motions is obvious，and the vibration control effect of MR dampers is significant when the structure is under various ground motions；the seismic reliability of each story as well as the whole structure is evidently enhanced after the installation of MR dampers.