The Base Isolation Research Of Reinforced Concrete Frame-shearwall Structure With Specially-shaped Columns

Structure with specially-shaped columns has developed very quickly in our country.There are many advantages promoting it developed so quickly, for example, thebeautiful appearance that the thickness of specially-shaped columns limb and the wallare the same so that the edges and corners of columns are not exposed to improve theutilization of the indoor area. However, the complexity of specially-shaped columns inforcing limits its range of applications and development. This paper presents the seismicisolation technology is applied in specially-shaped columns frame-shearwall structure toreduce the internal force of the structure in earthquake in order to make thespecially-shaped columns used in a broader context.First, the basic principle of isolation is expounded. Through the addition of leadrubber bearing (LRB) under the structure, the growth of structural natural vibrationperiod of structure and increasing damping can be caused so that the natural vibrationperiod of building can be away from the design characterization period of groundmotion. The response of the upper structure is reduced greatly. Secondly, this paperpresents the principles of the LRB setting and choosing and the details of constructing.The principles of LRB arrangement not only satisfy the design requirements of thevertical bearing capacity, but also the layout is reasonable. And the economic conditionsshould be considered, so the types of LRB should not be too much. Thirdly, the modelof a actual project is established and the seismic response analysis is done by usingfinite element software SAP2000for multi-earthquake and rare earthquake. The resultshow that: the seismic effect of the structure is significantly improved by applying baseisolation technology. The top acceleration decreases by about40%~60%and theinterlaminar shear decreases by about50%. In rare earthquake the maximum displacement of the isolation layer does not exceed the maximum allowabledisplacement of code requirement. The last, some models of overrun specially-shapedcolumns structures that are different heights and layers are established.Some usefulconclusions are obtained through doing seismic response analysis and comparing theseresults for multi-earthquake.The results show that: isolation design is an iterative process of calculation, settingthe isolation layer need to consider economic factors and safety factors together. Thestructural natural vibration period is extended by settings isolation layer. In this project,the drift angle and the story shear force are effective to reduce about40%~90%by usingbase isolation technology. Under the condition of the same arrangement of LRB, theinterlayer shear and displacement are not a substantial increase as the height increases.But the aspect ratio can not exceed certain limits that should be researched more deeply.The results show that the application of base isolation technology in specially-shapedcolumns frame-shearwall structure is feasible with good seismic effect and also makethe building height.