地震动持时对自复位预应力混凝土框架动力响应的影响

Investigation on the Influence of Ground Motion Duration on the Seismic Response of Self-Centering Prestressed Concrete Frames

为研究地震动持时对具有半刚性特征的自复位预应力混凝土(SCPC)框架动力响应的影响,以一8度设防地区的摩擦耗能型SCPC框架为分析算例进行分析。利用OpenSees有限元分析软件建立其有限元模型,基于规范反应谱拟合生成2组(20条)持时分别为20 s和60 s的地震波为激励,对结构进行设防烈度地震和罕遇地震下的非线性动力时程分析。结果表明:设防烈度地震水平,持时对结构动力响应的影响较小,结构可较好地实现震后立即使用的性能目标;罕遇地震水平,短持时地震作用下SCPC框架可较好地实现震后可修的性能目标,而长持时地震会导致SCPC框架的下部楼层侧移和残余位移过大,梁柱损伤加剧,结构不易实现“大震可修”性能目标。

To investigate the influence of ground motion duration on the seismic response of self-centering prestressed concrete(SCPC)frames characterized by semi-rigidity,a friction based SCPC frame located in the area with a seismic fortification intensity of eight degree is selected as the analytical case,and its numerical model has been built.Two sets of artificial ground motions with 20 s and 60 s duration,generated based on code response spectrum,were used as the excitation for structures.The nonlinear dynamic analyses were performed on the SCPC frame under moderate and major earthquakes through finite element model of OpenSees.Results show that the ground motion duration has minor influence on the seismic response of structures under moderate earthquakes and the structures can be used immediately.Under major earthquakes,the structure can achieve the performance objective of repairable under the earthquake with short duration,while long ground motion duration may lead to larger displacement and residual deformation of lower floors,and aggravate the damage of beam and column,the objective of repairable under major earthquake is not achieved easily.