In order to cope with excessive displacement requirements of the isolation layer in the base isolated structure，a hybrid isolation system is proposed in this paper through the base isolated system （BIS） + tuned tandem mass dampers-inerters （TTMDI）. The Bouc-Wen hysteretic model is used to simulate the nonlinear force-deformation behaviors of the isolation layer. Employing the stochastic equivalent linearization，pattern search optimization algorithm，as well as the earthquake ground motion model simultaneously，the optimum design framework of the BIS+TTMDI system is established in the frequency domain. The performance of the BIS+TTMDI system is systematically evaluated in terms of its robustness，effectiveness，stiffness and damping coefficient，stroke and sensitivity to seismic frequency contents，and compared with BIS + the tuned mass damper （TMD），tandem tuned mass damper （TTMD），and tuned mass damper-inerter （TMDI），respectively. The dynamic elasto-plastic analysis of a seven story hybrid base-isolated system，respectively including the BIS+TTMDI and BIS+TMDI systems，is carried out under the near-field earthquake ground motions. The results show that the BIS+TTMDI system has the best seismic performance and strong robustness. Furthermore，the total damping requirement of the TTMDI in the BIS+TTMDI system is less than half of the TMDI in the BIS+TMDI system，which is more economical and practical.

Based on the actual project in Dalian，this paper studies the dynamic interaction （SSSI） of the double tunnel sand bridge pile system under earthquake through shaking table test，obtains the dynamic response law of structure and site，and compares it with ABAQUS numerical simulation. The Kelvin constitutive model subroutine is introduced into the numerical model，and the equivalent linear method is used to deal with the nonlinear problem of sand in the calculation process. The experimental results are compared with the numerical model to verify the reliability of the numerical simulation. On this basis，eight working conditions are designed，and the interaction law between structures in the system is studied through comparative analysis. The results show that the tunnel will amplify the peak acceleration of the bridge pile and adjacent tunnel，but the bridge pile will weaken the peak acceleration of the side tunnel； the existence of the tunnel and bridge pile will increase each other's section shear force and bending moment. The main affected areas are concentrated in the upper and lower arches of the tunnel and the interface between the pile bottom of the bridge pile and the pile-soil.

The II-shaped composite girder is widely used in the construction of long-span cable-stayed bridges，but the weak vortex-induced vibration （VIV） performance of this type of section seriously limits its application prospects. A II-shaped composite girder double-tower cable-stayed bridge with a main span of 530 m is used as the engineering background，and the VIV performance and aerodynamic optimization measures of the II-shaped composite girder are studied by using wind tunnel tests. The tests show that the VIV of the original II-shaped section occurs at each wind attack angle，and the VIV amplitude of the girder can be reduced by setting guide vanes and the lower central stabilizer. The change in the inclination angle of guide vanes has a significant impact on the combined aerodynamic measure of VIV suppression performance. The combination measure VIV suppression performance with the guide vane of 30° inclination angle is the best，and the VIV can be significantly suppressed or even eliminated when the damping ratio required by the specification is 1.0%. The VIV suppression mechanism of the combined aerodynamic measure and the influence mechanism of the guide vane inclination angle change on the VIV suppression performance of the measure are studied by using computational fluid dynamics （CFD） numerical simulation. The calculation results show that the windward side guide vane in the 30° inclination guide vane combination measure can significantly improve the gas flow around the upstream section，and the cooperation with the lower central stabilizer can weaken the Karman vortex of the II-shaped section wake toy suppress the girder VIV. Changing the inclination angle of the guide vane not only affects the generation of vortices near the guide vane itself，but also affects the improvement of the lower central stabilizer on the vortex shedding state under the section，thereby significantly affecting the VIV suppression performance of the combined aerodynamic measure.

The determination of the rocking state for an isolation structure is a fundamental issue to estimate the safety of the isolated layer under a seismic excitation. In this study，by using the tensile deformations at the vertical direction of the rubber support in the isolated layer，the rocking states of the isolation structure are divided into ones with unuplifting，uplifting，and rocking. A classification method is then proposed for estimating the rocking state of the high-rise structure with isolated layer. Inspired by the influences of the aspect ratio （AR），vertical yield-weight ratio （α_v），horizontal yield-weight ratio （α_h），vertical cycle （T_v），horizontal cycle （T_h），system damping ratio（η） to the swing response of isolation structures under seismic excitation，boundary spectrum of isolation structures is achieved. It shows that swing response decreases with the increase of α_v，T_h and η （the effect of T_h is most significant），which is beneficial to the control of the sway response as well； swing response increases with the increase of AR and T_v （the effect of T_v is most significant），which is not conducive to the control of swing response，and the most advantageous measure to control the swing response is increasing T_h，decreasing T_v.

In order to improve the application of the damping force of isolation device for free-standing objects，a new damping mechanism is developed. Its structure and working mechanism are expounded，and its mechanical characteristic is deduced and verified. Combined with the target performance of an isolation device for cultural relics，the parameters of the damping mechanism are designed by numerical method，and contrasted with the shaking table test. The results indicate that the damping mechanism has a simple structure and stable performance. The isolation device optimized by damping parameters achieves the set isolation target under the premise of meeting the displacement limit. The test results are highly consistent with the numerical analysis results，which not only prove the correctness of the damping design，but also verifies the installation quality and operation effect of the isolation device. In addition，the coincidence degree between two results can provide a new method for design comparison and quality evaluation of the isolation device，especially the coincidence degree of relative displacement curves.

The constant erosion of ocean waves seriously affects the safe operation and service performance of ocean engineering equipment，and ocean wave energy is a green renewable energy with many advantages. How to reduce the wave load and utilize the ocean wave energy through the hybrid wave attenuation and energy harvesting structure is one of basic scientific problems in the field of ocean engineering. The traditional wave attenuation and energy harvesting structure，especially the floating structures in the deep sea，has the technical bottleneck of wave attenuation and energy harvesting at a low frequency range. In this paper，based on the idea of reducing the equivalent dynamic stiffness of the system，a nonlinear hybrid wave attenuation and energy harvesting structure is proposed，and the characteristics are studied. A new type of negative stiffness mechanism is designed and applied to hybrid wave attenuation and energy harvesting structure. In order to solve the fluid-structure interaction problem of nonlinear hybrid wave attenuation and energy harvesting structure，a semi-analytical nonlinear frequency domain method of hybrid eigenfunction expansion matching method and multi-harmonic balance method is proposed. The influence of the key parameters of the mechanism on the wave attenuation and energy harvesting performance is studied，and the “phase control” mechanism of the negative stiffness mechanism to improve the low frequency wave attenuation and energy harvesting performance is revealed.

The construction of a new power system requires to improve the response time of pumped storage units. In this paper，taking a specific pumped-storage unit as an example，systematical research is performed on the main differences of sequence control process and the variation law of unit stability parameters under normal and fast pumping to generating mode. Based on that，the inverse-time vibration evaluation method is introduced to evaluate the impact of transition modes on the unit vibration peak-to-peak values. By analyzing the pressure fluctuation in the vaneless zone with the frequency spectrum analysis method，the phenomenon of hydraulic resonance in the vaneless region at low speed is found in generating rotation，and the correlation between resonance amplitude，frequency and speed is revealed. The research indicates that the mode transition from pumping to generate the fast transition is better than the normal transition. Compared with the braking method of electrical brake plus mechanical brake in normal transition，the hydraulic braking mode under fast transition can significantly shorten the transition time from 438 s to 220 s. From the perspective of vibration damage to the unit，13 of the 14 vibration and runout monitoring points prove that fast transition is conducive to prolong the expected life of the unit. Meanwhile，the fast transition is favorable to pass the hydraulic resonance occurring in vaneless zone at low speed. The hydraulic resonance time is reduced from 15 s in normal transition to 5 s in the fast transition，and the resonance speed range is compressed by more than 60%.

The synchronization factor is a measurement for the consistency of actions between individuals in a jumping crowd，as well as a key metric in the modeling of crowd jumping loads. Most of the existing synchronization factors are defined as mean parameters during a long period of time，and thus cannot accurately reflect the time-varying characteristics of individual differences between jumpers. Their calculation is based on ground reaction force or feature point trajectory records that can only be obtained under laboratory conditions，making it difficult to apply them to the safety operation and maintenance of the engineering structures in actual scenarios directly. In this regard，this paper proposes a new time-varying synchronization factor for crowd-jumping loads. By introducing multiple objects tracking technology to monitor the real-time synchronization variation of the subject jumping processes as the basis for the factor calculation，this study carries out a multi-person jumping experiment with a wireless force measurement shoe pad. By comparing with the test results，the validity of the proposed time-varying synchronization factor and the effectiveness of the multi object tracking technology are verified. The results can be used for the intelligent operation and maintenance of the engineering structure，as well as the simulation of the time-varying crowd jumping loads.

The robust dynamic topology optimization of a continuum planar structure is studied to reduce its natural frequency variation when the structural material parameter uncertainties are considered. The uncertainties of the material properties are represented with the uncertain-but-bounded interval variables based on the non-probabilistic convex model. The dynamic topology optimization model for maximizing the first natural frequency is constituted by mitigating its variation，such that the robust optimization problem can be simply solved into a single-level framework. By the derivative analysis of the material parameters，a quadratic Taylor series expansion of the first natural frequency is obtained，and the design sensitivity of the natural frequency is accordingly evaluated in an explicit form under the uncertain material properties. By means of the material density-based strategy，the robust dynamic topology optimization is implemented with the material volume constraint，and the results are compared with those of the deterministic topology optimization. Optimal results show that the first-order natural frequency obtained with the proposed method has a higher robustness against the material property uncertainties，which fully demonstrates the importance of considering the uncertainties of the material parameters in the structural design stage.

Aero-elastic model wind tunnel test is carried out for a 1/3 rise-span ratio capsule-shaped pneumatic membrane structure，the characteristics of the wind-induced aero-elastic response of the structure are studied and the wind-induced dynamic vibration coefficients for practical design reference are given. The research confirms that the averaged deformation of the structure shows a trend of windward depression，top uplift and outward bulge in the transverse direction. This deformation trend is increasingly obvious with the decrement of internal pressure and the increment of wind speed. The averaged deformation and vibration amplitude decrease when the wind direction ranges from 0° up to 45°，then to 90°，and the extreme value of structural mean total displacements tends to appear at the center points of windward surface and top surface. Under 0° and 45° wind directions，the sort of vibration amplitudes of different components is vertical component，along-wind component and cross-wind component in descending order. Moreover，the structural vibration is dominated by the first-order mode. Under 90° wind direction，the amplitude of the crosswind direction is greater than two other directions，and the wind-induced vibration is dominated by the superposition of the first and second order modes. The internal pressure of the structure decreases in different extents under all cases. The response-based wind-induced dynamic vibration coefficients considering the fluid-structure interaction effect are given.