考虑结构整体特性的钢筋混凝土框架震后残余侧移响应研究

为了研究钢筋混凝土框架结构震后残余位移及结构整体特性对其影响,首先对3个楼层数不同的钢筋混凝土平面框架结构进行静力推覆分析,得到结构第一模态推覆曲线及相应等效三线形推覆曲线,进而基于等效推覆曲线获得结构整体的屈服后刚度比和下降段刚度比。其次,通过对钢筋混凝土平面框架结构在3个地震动强度水平、22条地震动记录输入下的弹塑性时程分析,分别计算得到最大层间位移角和最大残余层间位移角的平均值、标准差和变异系数,并分析结构整体特性如结构基本自振周期、屈服后刚度比、下降段刚度比等对最大层间位移角和最大残余层间位移角的影响,以及最大层间位移角和最大残余层间位移角之间的相关性。结果表明,最大层间位移角和最大残余层间位移角受结构基本自振周期影响明显,同一地震动强度水平下,两者均随结构基本自振周期的增大而增大。随着结构屈服后刚度比的增大和下降段刚度比绝对值的增大,最大残余层间位移角也增大,其离散性也随之变大。与上部楼层相比,高强度水平地震动下非线性发展较为充分的结构下部楼层的最大层间位移角和最大残余层间位移角的相关性较好。

Investigation on Post-Earthquake Residual Drift Response of RC Frames Accounting for Global Characteristics of Structures

In order to investigate post-earthquake residual drift responses of reinforced concrete frame structures and the effect of the global characteristics of the structures on them,firstly,three RC planar frame structures with different story numbers were analyzed by static pushover analysis,and the first-mode pushover curves and the corresponding equivalent trilinear pushover curves of the structures were obtained.Then the post-yielding stiffness ratios and post-capping stiffness ratios of the structures based on the equivalent pushover curves were calculated.Secondly,the mean,standard deviation and variation coefficient values of the maximum inter-story drift ratios and the maximum residual inter-story drift ratios were calculated by elasticplastic time history analysis of the structures under 22 ground motion records with 3 different scaled intensity levels.The influence of the fundamental period,the post-yielding stiffness ratio and the post-capping stiffness ratio of the structures on the maximum inter-story drift ratios and maximum residual inter-story drift ratios,and the correlation between the maximum inter-story drift ratio and maximum residual inter-story drift ratios were analyzed.The results show that the maximum inter-story drift ratios and maximum residual inter-story drift ratios are affected by the fundamental periods of the structures obviously.The maximum inter-story drift ratios and maximum residual inter-story drift ratios increase with the increase of the fundamental periods of the structures.With increase of the post-yielding stiffness ratios and the absolute post-capping stiffness ratios,the maximum residual inter-story drift ratios and their dispersion get larger.Comparing with the upper stories,the lower stories sustain adequate nonlinear deformation under high ground motion intensity levels and the correlation coefficients between the maximum inter-story drift ratios and maximum residual inter-story drift ratios become larger.