| In recent years, it is the most effective way that adopt engineering and technical measures to improve the seismic capacity of the structure, with the rapid development of engineering science and technical level in our country, a large number of engineering construction project of large and complex are built, and with the building that more and more high, the span more and more bigger, the structural system more and more complicated.But it is not mature applied to the large span space structure and it is to be further studied. Based on this, in this paper, the120m-span five-center-arc steel arch truss is studied, compare the dynamic response under seismic action of adopt isolation technology and non-isolation structure, and study the failure mechanism and the damping effect, while gave some suggestions with the base isolation design and analysis.Based on the existing rubber bearing isolation technology results at home and abroad, systematic study this technology on steel arch truss, the paper launched the following work:(1) Describe the threats to human by the earthquake and the significance of base isolation, analysis the existing state of isolation technology at home and abroad, according to the problems of base isolation and its development direction in future, determined the main contents of this paper. Analyze the basic principles of base isolation, elaborate the basic mechanical properties of the rubber bearing, and provide a theoretical basis for dynamic analysis of isolation structure in the Chapter Four. (2) Application the structural analysis software of SAP2000, do the response design on the120m span-five-arc steel arch truss, analysis its modal, state of stress and displacement.(3) Adopt plastic hinge theory, first analyze the failure state and failure mechanisms of the non-isolated structure and the isolation structure under X direction Hollywood, Lakewood and Rengong waves。(4) Second, compare the dynamic response (nodal displacement, internal force and nodal acceleration) of the non-isolated structure and the isolation structure under seismic waves (8degree moderate earthquake,8degree earthquake and9degree earthquake); Last, get the damping effect of isolation bearing on the arch truss structure, and the failure state and failure mechanisms under strong earthquake.Through analysis and comparison of the results obtained:(1) From the modal analysis we can know, adopt the isolation technology, it is significantly improved of structural vibration period, to avoid structural resonance, a greater degree of reduction of the structure of the earthquake, thereby the damage is reduced or even avoided to mankind under strong earthquake.(2) From the failure mechanism analysis of the non-isolation structure and the isolation structure, we can know the failure mechanism of the non-isolation structure and the isolation structure is same, all belong to the dynamic instability and failure, but the seismic capacity is improved of the isolation structure, the peak acceleration of the destruction of boundaries of the isolated structure is far greater than the non-isolation under the seismic waves, and slow collapse of the structure.(3) Shock in8degrees,8degrees earthquake and the major earthquake of9degrees, the relative displacement node of the isolated structure, rod axial force, the nodal acceleration than the original structure decreases significantly, especially in the9degree earthquakeunder the action of the original structure of the node relative displacement rod axial force, the node acceleration has the mutation, the performance response of the isolated structure are small, isolated structure greatly reduces the dynamic response of the structure, and earthquake, the strongerThe damping effect is more obvious. |
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