竖向地震动对带缝RC框架抗震性能影响的数值研究

Numerical study on the influence of vertical ground motion on seismic behavior of RC frame with construction joint

为研究竖向地震动对带施工缝RC框架结构抗震性能的影响,对7~9度区分别设计了4层规则框架结构,并对各框架结构建立考虑施工缝影响的数值模型,进行只输入水平地震波与同时输入水平和竖向地震波的非线性动力时程分析。对结构的顶点最大位移、层间位移角平均值以及塑性铰分布规律进行了对比,结果表明,竖向地震动对各烈度区带缝RC框架顶点最大水平位移的影响规律并不一致,可能使其增大或减小,主要取决于柱轴压比的变化规律。考虑竖向地震动影响会使各烈度区带缝框架的层间位移角增大,其中7度区框架的最大层间位移角超出了规范限值,9度区框架的层间位移角分布发生变化。竖向地震动会使构件端部提前出现塑性铰,并且柱端更容易出现塑性铰,梁端出铰较少。

In order to study the influence of vertical ground motion on seismic behavior of reinforced concrete（ RC） frame with construction joint,a serious of 4-story regular frames on 7 ~ 9 intensity seismic areas were designed. And the nonlinear dynamic time-history analysis under horizontal ground motion or both horizontal and vertical ground motions were performed to frames with construction joint. The maximum vertex displacement,the average interlayer displacement angle and the law of plastic hinge distribution of structure were compared. The results show that the influence law of vertical ground motion for the vertex maximum horizontal displacement of RC frame with construction joint is not consistent,which may increase or decrease the vertex maximum horizontal displacement of structure due to the law of columns axial compression ratio.Vertical ground motion increases the maximum interlayer displacement angle of structure. The values exceed the standard limits on 7 intensity seismic area and the distribution law changed on 9 intensity seismic area. Plastic hinges of rod ends appeared in advance and incline to appear in the end columns,beam ends appears less.