Study On Vibration Control Of Building Structures With Novel Multi-dimensional Earthquake Isolation And Mitigation Devices

Earthquake can cause detrimental effects on human production and life.Although the development of conventional vibration control methods is relatively mature in the field of engineering,due to the randomness and complexity of earthquake,these methods are difficult to provide a reliable guarantee for structures under various earthquake.Especially for some multi-dimensional earthquakes,it is hard for these conventional methods to perform effective both in horizontal and vertical.Therefore,in order to improve the multi-directional earthquake resistance of building structures,a novel multidimensional earthquake isolation and mitigation device(MDEIMD)is proposed in this paper,which is composed of an isolation bearing and serval cylindrical dampers.And this device has been applied to a vibration mitigation project of a primary school in Yunnan province.Based on the proposed device,the property tests are carried out respectively on its components at first to investigate the mechanical behaviors and energy dissipation mechanism.Next,according to the test results,the mechanical models which can be used to describe the characteristic of the device are proposed.Finally,the Yunnan primary school is selected as an example to investigate the control effectiveness by dynamic analysis and optimization design.According to the research contents above,the main completed word and conclusions are as follows:(1)Based on the high damping viscoelastic material,a novel MDEIMD which composed of isolation and mitigation capacity in horizontal and mitigation capacity and uplift resistance in vertical is proposed.The mechanical property tests are carried out on the viscoelastic material used internal and also on the core components of the device.The results indicate that the viscoelastic cushions and cylindrical dampers utilized in the device all have excellent energy dissipation capability and their mechanical will affect by the loading frequencies and amplitudes.Meanwhile,the nonlinear phenomenon of the corresponding hysteresis loops will be observed under large deformation.(2)Considering the characteristics of viscoelastic material,based on the microscopic molecular chain theory and continuum mechanics,the constitutive models that can be applied to describe the mechanical properties of viscoelastic materials under medium or small compression deformation and under large compression deformation are proposed.Then,on the basis of these models and further considering geometric relationship,the mechanical model of the MDEIMD is derived.Comparing these models with experiments,it can be found that the proposed constitutive models are in good agreement with the test results.And they can well describe the nonlinear hysteresis loops of the material and can also accurately reflect the change of the dynamic mechanical properties with the loading frequencies.(3)Taking the vibration mitigation project of a Yunnan primary school as an example,the control effect of the MDEIMD is investigated by the structural dynamic analysis under 22 earthquake waves.Meanwhile,a layout optimization of the device in actual three-dimensional structure is also conducted based on genetic algorithm and Matlab-Open SEES joint programming method.The analysis results show that the proposed MDEIMD have excellent performance both in horizontal and vertical direction.Furthermore,after appropriate optimization design,either the safety or economy of the structure can be effectively guaranteed.The innovations of this paper are as follows:(1)A novel MDEIMD which composed of isolation and mitigation capacity in horizontal and mitigation capacity and uplift resistance in vertical is proposed.This device combined with simple construction and excellent performance has been promoted to many practical engineering projects now.(2)The mechanical properties of viscoelastic materials under compression deformation are revealed by experiments.And the mechanical model which can describe the compression dynamic mechanical behaviors of the material are proposed.This model can accurately reflect the nonlinear force-displacement relationship under compression deformation and also well describe the influence of the frequencies and ambient temperatures on the mechanical properties of the materials.(3)Based on genetic algorithm and Matlab-Open SEES joint programming method,a layout optimization of the MDEIMD is conducted.After employing the parallel computing,the optimization of the device in actual three-dimensional structure is achieved.