Stability Analysis Of Steel Structure Considering Damage Accumulation Under Strong Earthquake

Steel frame structure system have a wide range of applications in high-rise civil buildingand industrial building, is one of the main structure system. Only based on the study of dynamicstability problem of the frame structure, we can obtain the system understanding of the problemthat avoid the collapse of frame structure under seismic action, so as to form seismic designtheory of frame structure. Earthquake is one of the important factors that causing structuraldamage. Structural damage will produce major effect on buildings. Therefore, consideringdamage in the study of dynamic stability is of practical significance.Using the theoretical analysis and comparison of various discrimination method of thedynamic stability. Through the dynamic stability analysis of a three-layer steel frame. Verifiedthe second kind dynamic stability is closer to the actual, and is more widely used.Through the analysis of structure damage principle. From taking the steel constitutivemodel into the damage model, using the example of steel frame, analyzed the influence ofcumulative damage effect during the process of earthquake to the strength and stiffness ofstructure. We can obtain the dynamic instability occurs easier when considering the damage.Thus it is necessary to consider the damage and it is practical.Using an engineering example, established two steel frame models, one defined aselastoplastic, the other considering damage. Applying seismic wave of various amplitude to thetwo models. Calculate the maximum displacement of the structure under every seismic wave.Analyzed the relation of maximum displacement and seismic wave amplitude. Using the secondkind dynamic stability theory, we can obtain the seismic limit loads of the structure dynamicinstability. While, the dynamic instability occurs easier when considering the damage. Underthe same seismic load, analyzed equivalent plastic strain of the element, we can obtain whenconsidering damage, equivalent plastic strain will larger, the structural response will larger.Using the finite element calculation, we can obtain the damage nephogram of the structure.Thereby obtain damage distribution of the structure and the damage of the unit. Provide thebasis for the seismic design of the structure.Through analyzing the residual bearing capacity of structure after seismic wave ofamplitude of A, defined global damage of structure using limit seismic load from the angle ofdynamic stability, analyzed the global damage amount of structure. Intuitively reflect thedamage situation of the structure. Provided the basis for repairing, strengthening and rebuildingof structure after seismic damage.