Dynamic Response Analysis of Steel Structure Based on the Combination of Vibration Reduction and Isolation

Based on the idea that the combination of seismic isolation and isolation could provide multi-channel seismic fortification for the structure, an application technology suitable for building high-rise steel structures in high-intensity areas was proposed. In order to study the shock absorption characteristics of high-rise steel structures with seismic and isolation devices, the layout rules of the inter-story isolation positions were compared and analyzed. The scheme arranged on the top of the column of the 4 th floor(at the sudden change in stiffness). The SAP 2000 finite element model of the traditional seismic structure(modelⅠ), the inter-story isolation structure(model Ⅱ) and the combined seismic isolation structure(model Ⅲ) was established, and the response spectrum analysis was carried out to obtain the natural vibration periods of the three structures, and the 8-degree(400 cm/s²) and The ground motion of 8 and a half(510 cm/s²) was calculated and analyzed, and the interstory displacement, floor acceleration, interstory shear force, hysteresis curves of isolation bearings and anti-buckling braces of the three structures were obtained by the groud motion analysis of 8-degree and 8 and a half degree of rare earthquake.
The results showed that:comparing model Ⅰ and model Ⅱ, under the action of the 8-degree(400 cm/s²) and 8 and a half(510 cm/s²) earthquakes, the displacement decreases of the Model III isolation layer were 10.5% and 14.8%, respectively; under the 400 cm/s² and 510 cm/s² earthquakes, the peak value of floor acceleration of model I increased gradually; compared with model I, the relative acceleration peak value of model II and model III decreased significantly at floors above the isolation layer, and the variation between floors was not large; compared with model II, the acceleration of model III was lower at floors below the isolation layer; the relative acceleration of the top layer of the model II structure was about 50% lower than that of the model I, and the relative acceleration of the top layer of the model III structure reduced by 60% compared with that of the model I; the maximum shear force ratio of the floors below the seismic isolation layer of the model II and model III under the action of 400 cm/s² was 0.710 and 0.613 respectively. and 0.449 and 0.427 for the floors above the seismic isolation story, respectively; under the action of 510 cm/s², the maximum shear ratios of the floors below the seismic isolation story of model II and model III were 0.741 and 0.602, respectively, while those above the seismic isolation story were 0.421 and 0.389, respectively; the hysteresis curve of the lead-core isolation bearing(LRB) under rare earthquakes was full, and the maximum displacement reached 161.6 mm(510 cm/s²) and 124.5 mm(400 cm/s²), which consumed most of the seismic action. The hysteresis loop of model Ⅲ used lead-core isolation was smaller than that of model II, which indicated that the bottom buckling bracing(BRB) shared the part of the seismic action, and the hysteresis loop under 500 cm/s² was significantly larger than that of 400 cm/s². It showed that the shock absorption effect of the structure arrangement of the shock isolation device on the upper floors was more significant, and from the perspective of the whole structure, the shock absorption effect of the combined seismic isolation structure was better than that of the floor isolation structure, and the isolation was reduced under the action of higher intensity earthquakes. The seismic combination showed better shock absorption performance and could provide more safety for the structure.