Study On Seismic Behavior Of Space Steel Structure With Central Support Based On Dynamic Test

Steel frame structure is widely used for its advantages such as light weight,fast construction and green environment protection.Compared with foreign countries,the research of steel structure civil construction in China is not deep enough.During the construction and service of steel structure,it is unavoidable to suffer various kinds of infringement,such as earthquake,fire,impact,material aging,mechanical vibration,etc.so it is necessary to carry out the working modal monitoring of the building structure,and use the measured data to make the safety evaluation of the structure.In recent years,with the rapid development of steel structure building,it provides an objective condition for the study of dynamic characteristics and seismic performance of steel structure.The dynamic characteristic analysis of the structure is an effective means to understand the seismic performance of the structure,the working modal parameters of the steel structure are measured by pulsating method,the theoretical calculation results can be verified,and the practical formula of structural dynamic characteristic is deduced,which provides basis for the damage identification and safety evaluation of the steel structure.In this paper,the natural environment micro-vibration as the excitation source,without any damage to the structure of the premise,to obtain the structure of the vibration frequency,damping,vibration type and other dynamic parameters,for the next step of seismic response analysis laid a foundation.According to the test results,using SATWE and Ansys software to establish the finite element model,using subspace iterative method to extract the period and mode,and the natural frequency as the basis for judging whether the structure model is reasonable,to measure whether the structural quality and stiffness match,stiffness is reasonable,The finite element model,which conforms to the actual structure,is established to study the seismic response of structures.The seismic design analysis based on the sexual state is carried out by means of numerical simulation.By setting up a control model,the seismic responses of pure frame structure and central braced frame structure under 7,8 and 9 degree earthquakes undermultiple earthquakes,fortification intensity and rare earthquakes are obtained respectively,and their respective yield mechanisms are clarified.At the same time,the collapse limit point of steel structure is studied by incremental dynamic analysis based on dynamic time-history analysis,According to the principle of the input ground motion characteristic and the construction site condition,the ground motion record is chosen reasonably,and the spectral Acceleration SA and the maximal interlayer displacement angle corresponding to the T1 of the basic periodic structure are selected as the intensity index IM,the damage index DM,and the IDA curve and the collapse limit point are obtained after several.It can be used as a reference for the study of dynamic characteristics and seismic behavior of similar structures.