Based on the elastic foundation beam theory，the mechanical model for the seismic response of the vertical shaft is established. The shaft primary lining and secondary lining are simplified as Euler Bernoulli beams and the normal interaction between the primary lining and secondary lining is simulated by using uniformly distributed springs. The differential governing equations of the shaft under the horizontal seismic excitation are derived. The rapid solution of the horizontal seismic response of the primary lining and secondary lining is achieved through the distributed transfer function method and the correctness of the analytical solution is verified by comparison with the finite element numerical simulation method. The peak seismic response at the top of the shaft is parametrically analyzed from the perspectives of elastic foundation stiffness，secondary lining stiffness，shaft outer diameter，and stiffness of the elastic connection layer between the primary and secondary linings，respectively. The results show that the peak seismic response at the top of the secondary lining is greater than that of the primary lining. With the increase of the elastic foundation stiffness，the peak response of the top of the primary lining and the secondary lining decreases. The increase of secondary lining stiffness leads to the obvious increase of peak response at the top of secondary lining. With the increase of the shaft outer diameter，the peak response of both the primary and secondary linings increase significantly. When the elastic connection layer stiffness increases，the peak response of the primary lining increases slightly，but the peak response of the secondary lining decreases significantly.

In the processing of near-fault original seismic acceleration records，how to retain the real ground permanent displacement information is a key problem to be solved in the baseline correction of seismic acceleration records. Based on the analysis and discussion of the validity and applicable scope of existing near-fault seismic acceleration baseline correction methods，this study introduces a smooth slope displacement function model and establishes a new baseline correction method that can reasonably characterize the permanent displacement of near-fault ground motions，and the new baseline correction method is verified by analyzing the baseline correction results of typical near-fault acceleration records. The results show that the new method established in this study improves the fitting accuracy between the displacement function model and displacement time history，reduces the influence of the selection of subjective parameters on the baseline correction results，and the corrected ground permanent displacement is in good agreement with the GPS co-seismic displacement. The ground motion baseline correction method established in this paper can not only automatically deal with the baseline drift of near-fault ground motion，but also reasonably characterize the permanent ground displacement caused by fling-step effect.

Plane irregular buildings are prone to torsion and cause serious damage to the structure. The analysis and control of structural torsion effect is the key to this kind of structural design. In this regard，the simulation calculation of the planar irregular multi-story frame model in the 8-degree fortification zone was carried out，and the planar L-type four-story frame isolation model of five typical class B buildings was established. The ratios of the length B and width W of the protruding limbs of the structure were set to be 1∶1，1.5∶1，2∶1，2.5∶1 and 3∶1，respectively. The dynamic characteristics and seismic response of different structures were analyzed. The influence of the LRB stiffness ratio and the rigid center position of the isolation layer on the structural torsion was discussed，and the effective control method of structural torsion was proposed. The results show that with the increase of the length-width ratio B/W of the protruding limb，the X-direction torsion of the structure increases gradually，and the Y-direction torsion decreases gradually. Increasing the proportion of LRB stiffness can reduce the torsional effect of the structure. By comprehensively controlling the structural torsion and structural damping coefficient，a reasonable proportion of LRB stiffness can be obtained. The proportion of LRB stiffness of the isolation layer under the condition of 8 degrees earthquake is proposed. At the same time，the rigid center of the isolation layer and the rigid center of the superstructure are arranged on both sides of the mass center of the superstructure to suppress the torsion of the superstructure of the plane irregular structure.

A practical analysis method for inertia damper energy dissipation systems composed of building structures with inertia dampers is proposed，including of concise closed-form solutions for the random seismic response and a practical setting strategy for inertia dampers. Based on the mechanical structure diagram of the series inertial damper and installation method in buildings，the coupled seismic motion equation of the energy dissipation system is established. In response to the difficulty in solving the damping and stiffness parameters in the actual dynamic equations of structures，an equivalent form of the uncontrolled structure represented by real modal vibration parameters is obtained based on finite element technology and dynamic principles，and the dynamic equation of the inertia damper energy dissipation system is reconstructed. Based on the quadratic decomposition method of the power spectral density function，closed-form solutions of the spectral moments of the building structure relative to ground displacement，interlayer displacement，and inertial damping force are derived. The correctness of the proposed concise closed form solution is verified through numerical examples，and the influence of real mode number on the 0~2 spectral moment of series response and the influence of floor position of inertia dampers on the seismic reduction effect of structures are studied. Results show that，using the number of actual vibration modes corresponding to the cumulative participation coefficient of 100% in the free vibration analysis of uncontrolled structures can achieve stable analysis accuracy and computational efficiency for the response analysis of multi-degree of-freedom energy dissipating structures，and to use reducing interlayer displacement of uncontrolled structures as the placement strategy for installation of inertial dampers is simple and feasible. This paper can provide a reference for the analysis of random ground motion response of complex building structure with series inertia capacity system.

To achieve rapid recovery of structural function after the earthquake，based on the idea of replaceability and additional energy consumption，a new earthquake-resilient fully bolted beam-column joint is introduced in this study. The shortcoming of insufficient energy dissipation ability of the existing fully bolted joint loaded into large deformation condition is improved by setting up the T-shaped energy dissipator. The influence of the energy consumption length and slenderness ratio of the T-shaped energy dissipator on the seismic behavior of the new earthquake-resilient fully bolted joint is studied. Three new earthquake-resilient fully bolted joints and one welded joint were subjected to low-cycle loading. The results of tests show that the seismic performance of the new earthquake-resilient fully-bolted joint is better than that of the traditional welded joint. The new earthquake-resilient fully-bolted joint can concentrate the plasticity and damage，transfer the plastic zone to the T-type energy dissipation plate，and avoid the fracture of the welding zone at the beam end. In this paper，the lower limit of the length of the energy dissipation segment is given. When the energy dissipation segment has sufficient deformation length，and the cross-section area of the energy dissipation section is the same，the conservative slenderness ratio is determined to be 13.2，which can make the new joints have good bearing capacity and ductility，and give full play to the seismic performance of the new joint.

The seismic dynamic response of pile foundation in inclined liquefaction site is an important issue in the field of geotechnical seismic engineering. Based on the shaking table model test carried out by our research group and the OpenSees software platform，a two-dimensional integrated numerical model of inclined liquefied soil-pile group-structure interaction is established in this paper. The nonlinearity of pile-soil contact and the shear localization of soil layer are considered in the model. The rationality and effectiveness of the numerical simulation method are verified by comparing with the shaking table test results. On this basis，a typical inclined liquefied site-pile group-structure interaction finite element model is established to discuss the influence of different overlying crust on the seismic response of site and structure system. The calculation results show that with the increase of the thickness of overlying crust，the pore pressure ratio in the saturated sand decreases，the horizontal residual displacement of soil decreases，and the displacement of pile body and the pile curvature decrease. The effect of the strength of overlying crust on the dynamic response of pile foundation is more obvious. The increase of the thickness of overlying crust can reduce the liquefaction degree of sand and improve the mechanical performance of pile foundation.

Based on the porous medium theory and the continuum medium fluctuation theory，this paper studies the amplitude reflection and energy reflection properties of the plane P₁ wave reflection on the unsaturated semi-space free boundary. Using Helmholtz decomposition theorem and specific free boundary conditions，the analytical expressions of the amplitude reflection coefficient and energy reflection coefficient of four types of reflected waves （reflection P₁ wave，reflection P₂ wave，reflection P₃ wave，and reflection S wave） generated by the plane P₁ wave are obtained，and the effects of incidence and saturation，frequency and porosity on energetic properties is analyzed. The results show that the amplitude reflection coefficient and energy reflection coefficient not only are affected by the angle of incidence，but also have significantly changed with the change of saturation，and the reflected P₁ wave and reflected S wave carry the vast majority of the incident wave energy.

A vibration-controlled device with paired inclined nozzles is designed to reduce the barrel vibration and minimize the impact on the aircraft during continuous firing. The newly designed paired inclined nozzles generate only dynamic moment and recoil force，without producing transverse force. An interior ballistics model of the barrel with lateral channels is established，and the TVD-MacCormack difference scheme is utilized to numerically calculate the flow field in the barrel and the time-dependent aerodynamic force of the nozzles. Dynamic simulations of the continuous firing process of the aircraft gun are conducted to evaluate the effect of the paired inclined nozzles on the muzzle vibration. Results show that the time difference of the maximum aerodynamic force of the two nozzles is 0.07 ms，with a relative difference of the maximum aerodynamic force of only 0.5%. This indicates that the two nozzles are well synchronized. The paired oblique nozzles can greatly reduce the muzzle vibration without compromising the initial velocity of the projectile. The linear displacement and velocity of the lateral vibration decrease by 26.9% and 44.3%，respectively. The recoil momentum also decreases by 17.93%，without generating transverse force on the aircraft. As a result，the impact on the aircraft is significantly reduced. The achievements of this research will support the design of aircraft gun barrels with paired inclined nozzles.

Aiming at the robustness and stability of the vibration active control of motor-driven seawater pumps，a hybrid structure adaptive vibration active control strategy is proposed based on the Kalman filter （KF） algorithm，which establishes the system state prediction equations，state transfer matrix and measurement matrix，and builds a hybrid structure adaptive vibration active control system model. In order to improve the convergence performance of the algorithm，an online update strategy for the measurement noise covariance matrix is proposed. Simulation results show that the new control strategy effectively overcomes the strong correlation between the reference signal and the vibration source based on the classical Filtered x Least Mean Square algorithm （“FxLMS”），and realizes effective vibration active control under the premise that Gaussian white noise is used as the reference signal. The robustness，stability，and control effect of the proposed strategy are all superior to that of the FxLMS algorithm with a variable step size. The results provide theoretical support for engineering practice and have certain potential application value.

The complex response of the ocean thermal energy conversion platforms in the marine environment makes the structural safety design of cold seawater intake pipes suspended beneath the platform a challenge. Recent research has shown that the in-plane motion of the platform （heave oscillation） triggers out-of-plane vortex-induced vibration （VIV） in the riser connected to the platform and the complex vortex vibration response can cause rapid accumulation of fatigue damage to the riser，resulting in structural damage. In this paper，we focus on the VIV response of a free-hanging riser under multi-degree-of-freedom motion，which has rarely been reported in previous studies. A pool model test to measure the VIV strain information of the riser using fiber-optic grating strain gauges is carried out. After analysis of the experimental results，it can be found that： the maximum oscillation velocity at a large KC number is the main parameter affecting the dominant frequency of the out-of-plane vortex vibration response； the dominant frequency of vibration at a small KC number is twice frequency of the motion of the top platform. By comparing the experimental and numerical results of the free-hanging riser under the three degrees of freedom motion of the platform，it is found that the influence of the VIV on the overall dynamic response of the free-hanging riser is not negligible in this case. These results can provide a reference for further research on the VIV of the free-hanging riser taking into account the influence of the platform motion.