Seismic Control To The Multifunctional Vibration-absorption Mega-frame Structures

The mega-frame structure is a novel structure system adapting to the development of high-rise building. As the height and weight increased, definitely the mega-frame structure will bear much of wind load and horizontal earthquake action. Therefore, it is necessary to take damping control measures in mega-frame structures.According to different damping control measures, the structure control can be divided into different types, which are passive control, active control, hybrid control, semi-active control and so on. Generally speaking, the existing damping devices only have a single vibration function which restricts their damping effect. The multifunctional vibration-absorption mega-frame structures organically combines damping devices with mega-frame structure scheme. It sets damping devices in connections of primary-secondary frame structure which makes the structure anti-seismically.As for the seismic control of multifunctional vibration-absorption mega-frame structures, the author has given comprehensive research as following in the paper:â‘ On the basis of mega-frame structure design, the author set mezzanine rubber cushions as damping devices under every hypo-frame's bottom which forms multifunctional vibration-absorption mega-frame structures (shock absorption structures for short), and Software (SAP2000) was used to comparatively analyze on the dynamic characteristics of aseismic structures and relevant shock absorption structures. The results showed that, the shock absorption structures'for each natural vibration period was longer than in aseismic structures. The first few order vibration mode shapes were hypo-frames'horizontal ones. The main frame's vibration mode shapes appeared after the twelfth order and the vertical vibration mode shape was appeared even later.â‘¡Time history analysis method was used to comparatively analyze on seismic response characteristics of aseismic structures and relevant shock absorption structures. The result showed that, shock absorption structures can remarkably minish structures'seismic response. The seismic response of shock absorption structures was mainly on the shear deformation of the rubber bearing. From the bottom to the top, the shear deformation was larger and larger.â‘¢The deformation of the isolation layer is very large in earthquake and in order to avoid primary-secondary frame structures'seismic pounding, the research was focused on analyzes the feasibility and effectiveness of setting viscous damper between hypo-frames'bottoms and main frame beams. In additional to, The author analyzed the influence of viscous dampers'location and damping coefficient C on the structural damping effect. The result indicated that 1) setting viscous dampers in hypo-frames'bottom can not markedly control the main frame's semic respose, but it can effectively minish the hypo-frame's semic respose and the seismic isolation device's deformation, which can avoid primary-secondary frame structures'seismic pounding; 2) when the viscous damper's damping coefficient C was bigger, the structure's damping effect was more obvious. However, when C was very big, the damping effect was not obvious any more and it was even bad to the structure; 3) we should preferentially choose the top hypo-frame's bottom as the location of the viscous damper.â‘£A conceptual aseismic design has been put forward about multifunctional vibration-absorption mega-frame structures. The damping device is the first element of anti-seismic; the hypo-frame is the second one; and the main frame is the last one.