| The base isolation technology is an effective means to improve the seismic capacity of the structure and protect the seismic safety of the building.However,most of the currently used isolation devices do not have the function of isolating vertical ground motion,and a large number of strong earthquake observation records indicate that the potential threat of large vertical seismic components to building structures and non-structural components cannot be ignored.One of the difficulties in achieving three-dimensional isolation is the rocking problem of the isolation layer under the action of three-way earthquake.Under the action of three-way earthquake,the superstructure will have a large overturning moment on the foundation,causing the isolation layer to lift off and the tensile deformation of the corner support.In the horizontal isolation structure,there is a risk of excessive tensile deformation of the support,failure of the support,and collapse of the structure.The vertical dynamic stiffness of the three-dimensional isolated structure is generally low and the anti-swaying ability of the isolation layer is weaker in order to achieve the vertical damping effect,so that the sway suppression problem under the action of the three-way earthquake becomes more and more prominent.The dynamic analysis model and the rocking effect of three-dimensional isolated structure are studied.The dynamic equation of translation-swing-torsion is deduced theoretically.The rocking effect of three-dimensional isolated structure is analyzed.The rocking response spectrum and the rocking suppression device are put forward.The main work is as follows:(1)The dynamic equation of three-dimensional isolated system is deduced theoretically.The dynamic response characteristics of translation-swing coupling in plane of rigid body model and multi-layer model and the response characteristics of translation-swing-torsion coupling in space of three-dimensional isolated structure are studied.The horizontal,vertical and rocking decoupling of the motion differential equation of the undamped forced vibration system is carried out by solving the mode shapes.(2)The maximum values of the rocking response,the acceleration response and the displacement response of the isolated layer under one-way horizontal ground motion input,two-way horizontal ground motions input and three-way ground motions input are studied.The peak value of rocking angle,acceleration,displacement rocking response is established.(3)The rocking response of the structure with different parameters such as eccentricity,height-width ratio,vertical period and rocking period is studied.The theory of optimum parameter design is put forward,by establishing the structural dynamic control index of the seismic response of the three-dimensional isolated structure.The parameter impact analysis of the shaking table test frame structure model is proved to be reliable.(4)The rocking suppression device is designed.The structure and deformation mechanism of the rocking suppression device applied to three-dimensional isolated structure are studied.The horizontal/vertical follow-up deformation characteristics and rocking suppression mechanism of the rocking suppression device are studied.The ultimate deformation of the rocking suppression device is also studied.The rocking suppression device is applied to the three-dimensional isolated structure for numerical analysis,which proves the efficiency of the proposed device. |
