| Non-structural building components,such as equipment,evolve when the demand for functional requirements of the building structure increase.The building structure itself and the internal equipment together form a coupled structure-equipment system.Most studies on the structure-equipment system assume that the ground is rigid.In fact,differences between the actual foundation conditions and the assumptions may lead to unreasonable or even unsafe conditions in the design of the structure-equipment system.On the one hand,the relative flexibility of the soil can change the dynamic characteristics of the structure-equipment system;on the other hand,the far-field energy dissipation effects caused by the infinite foundation will further change the seismic response mechanism of the structure-equipment system;hence,only a combined analysis of the soil,structure,and equipment can reflect the real situation.However,due to the complicated interaction effects within the soil-structure-equipment system and the enormous size of the system,there is still a lack of efficient calculation methods applicable to the entire system,and experimental studies are even scarcer.On this basis,the study investigated the modeling of the far-field energy dissipation effects,conducted a shaking table test method for the soil-structure-equipment system,and explored the basic issues involved in the energy-based seismic design of the system.A theoretical analysis of the seismic energy response of the equipment-structure system considering the complex interaction effects have been investigated.The energy input and dissipation mechanism of the structure-equipment system under real foundation conditions have been analyzed.The key research activities are as follows:(1)A combination of the component modal synthesis method and damping extraction method is proposed to simulate the far-field energy dissipation effect.The theoretical basis of the combined method is studied,and the time-domain finite element calculation equation of the combining method is established.The finite element model for simulating far-field soil effects is realized using ANSYS and MATLAB.The Simulink state-space method is applied to the calculation of the far-field soil.The reliability of the proposed method is verified based on Simulink.The results show that the proposed far-field energy dissipation simulation method can achieve good accuracy at a small calculation scale.(2)A real-time hybrid shaking table test method based on the branching mode substructure method is proposed.The motion equation of the soil-structure-equipment system is derived and transformed,so that the interaction effects between the structure-equipment system and the soil appears in the form of coupling loads to enable the data interaction between the experimental substructure structure-equipment system and the numerical substructure soil.The simulation of the rotational effect of the soil on the one-way loading of the shaking table device is studied and simulated by the equivalent load method,and a real-time hybrid shaking table test method for the soil-structure-equipment system is put forward.The model of numerical substructure soil and its implementation is investigated.The feasibility of application of the proposed reduced soil model in a real-time hybrid test shaking table is demonstrated.The results show that the proposed reduced soil model has higher accuracy and meets the data interaction requirements of the real-time hybrid shaking table test.(3)The calculation method of the seismic energy response of the structure-equipment system considering the influence of the soil is put forward.The analytical foundations of the energy response of the structure-equipment system considering the linear and local nonlinear stages of the soil is studied,and the corresponding computing is realized by self-programing.Different forms of connecting support devices between the equipment and the structure are included,and the energy response calculation equations of the equipment,structure,and connection device are obtained.The real-time energy response output of the equipment and structure in Simulink is studied,and the corresponding real-time energy response output module is developed.The energy response of the high rise structure-equipment system is obtained using MATLAB,which lays the foundation for studying the actual energy demand and dissipation mechanism of the structure-equipment system.(4)A real-time hybrid shaking table test of the structure-equipment system and soil-structure-equipment system is realized,and the reliability of the real-time hybrid shaking table test method based on the branching mode substructure method is verified.Based on the test results,the influence of the connection device parameters and soil on the energy response of the structure-equipment system is investigated.The results show that: compared with the rigid connection device,flexible connection devices can reduce the input energy and hysteretic energy ratio of the structure;the influence of the parameters of the connection device on the input energy and its distribution in the equipment is related to the ground motion characteristics.After considering the influence of the soil,the input energy of equipment and structure is reduced relative to that of the rigid foundation;the energy distribution characteristics of the equipment and structure changed,and the influence rule of the connecting device parameters on the energy of the equipment and structure are altered.The energy calculation results of the structure-equipment system on the rigid foundation assumption have large errors.(5)The analysis of the soil-structure-equipment system considering the local nonlinear effects of the soil is put forward.The combined ANSYS-MATLAB method that utilizes the properties of both software effectively is investigated.The ANSYS-MATLAB interactive calculation platform is developed,and the reliability of the calculation method is verified.Based on the interactive calculation platform,the influence of local nonlinear effects of the soil on the energy response of the structure-equipment system with different connection devices is investigated.The results show that the reduction effects of soil on the input energy of the structure-equipment system is weakened after the soil enters the local nonlinear stage.At the same time,the influence patterns of the local nonlinear soil on the energy response of the structure-equipment system is different from that of linear soil assumption.It is necessary to consider the local non-linear behavior of soil in the analysis of the structure-equipment system.(6)Energy response analysis of the soil-high rise structure-equipment system is carried out.The input energy,energy dissipation mechanism and means of performance coordination involved in the energy-based seismic design method of high rise structure-equipment system considering the effects of soil are investigated.The effects of the parameters of the connection devices and the soil on the input energy,energy distribution,and energy consumption mechanism of the equipment and structure are analyzed.The results show that the flexible connection device is beneficial to the reduction of the energy input to the equipment.When the basic frequency ratio of the equipment subsystem and the structure is close to 1.0,the energy input to the structure can be significantly reduced.Flexible connection device is conducive to the reasonable distribution of energy of the equipment and the seismic response control of equipment.Changing the parameters of the flexible connection device can coordinate the performance of the equipment and the structure.When the basic frequency ratio of the equipment subsystem and the structure is close to 1.0,the equipment and the structure can achieve an interactive shock absorption state;the results based on the rigid foundation assumption overestimate the input energy of the structure and the equipment.The reduction in energy input to the structure and the equipment can be up to 50%;after considering the influence of the soil,the input energy distribution pattern in the structure and equipment is changed,and the distribution of hysteretic energy consumption of the structure is altered,which leads to differences in the damage characteristics of structure compared to that of the rigid foundation assumption;after considering the influence of soil,the influence patterns of the connection device on the structure energy response is obviously different from that of the rigid foundation condition,and the advantages of the flexible connection device on the equipment is weakened.Therefore,it is necessary to consider the influence of soil in energy-based seismic design of the structure-equipment system. |
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