基于基底剪力降低率的消能减震设计

ENERGY DISSIPATION AND SHOCK ABSORPTION DESIGN BASED ON BASE SHEAR REDUCTION RATE

为解决在实际地震中难以对粘滞阻尼器附加有效阻尼比取值问题,优化粘滞阻尼器的实际应用,引入基底剪力降低率这一概念,并以结构的基底剪力降低20%为目标,设计了粘滞阻尼器布置方案,运用ETABS有限元软件对其进行动力时程分析,并以墙式连接为例,探究了粘滞阻尼器布设点如何影响消能减震效果。结果表明:在多遇地震下,通过在x向、y向布设粘滞阻尼器,可提供给结构附加阻尼比,分别为6.75%和6.72%,并满足了消能减震设计的预期目标;在罕遇地震下,建筑结构的最大层间位移角、层间侧移、层间剪力均未超出规范限值;粘滞阻尼器连接墙布设点从柱端向跨中位置变化时,附加阻尼比与其间距成正比。因此,将结构基底剪力减少20%,计算所需的附加阻尼比的消能减震设计方法,能够确保结构在罕遇地震情况下具备符合规范要求的消能减震效果。

In order to address the difficulty in evaluating the effective additional damping ratios of viscous dampers in earthquakes and optimize the applications of viscous dampers,the base shear reduction rate was introduced.Aiming at reducing the structural base shear by 20%,a viscous damper layout scheme was designed,and the dynamic time history was analyzed with ETABS finite element software.Taking wall connection as an example,the impact of the viscous damper layout on energy dissipation and shock absorption was explored.Results show that,where earthquakes occur frequently,viscous dampers can be set in x and y directions to increase the additional damping ratio of structures by 6.75%and 6.72%respectively,which is consistent with the expectations of the energy dissipation and shock absorption design;where earthquakes occur rarely,the maximum inter-storey displacement angle,inter-storey lateral displacement and inter-storey shear of buildings and structures do not exceed the limits stipulated in specifications;and the additional damping ratio is proportional to the spacing of viscous dampers on walls between the column end and mid-span.The energy dissipation and shock absorption design involving a reduction of structural base shear by 20%and calculation of the required additional damping ratio can ensure the compliance of structures with the energy dissipation and shock absorption requirements of specifications in rare earthquakes.