柱端弯矩放大系数对“强柱弱梁”实现的影响

为探究柱端弯矩放大系数对实现"强柱弱梁"的影响,本文采用ABAQUS有限元软件,建立了不同柱端放大系数的9个钢筋混凝土(RC)框架结构梁杆单元模型,通过动力弹塑性分析,分析了不同弯矩放大系数下结构层间位移角和塑性铰的变化与分布情况。结果表明:随着柱端弯矩增大系数ηc的增大,最大层间位移角显著降低,但ηc达到一定值时变化趋于平稳;柱端弯矩系数的增大改变了梁柱节点的破坏形态,不同节点和不同楼层实现"强柱弱梁"破坏形式的难易程度不同,角节点和地震动方向上的边节点较中柱所在节点和与地震动垂直方向的边节点容易产生强柱弱梁型节点,顶层较底层和中间层容易产生强柱弱梁型节点。结果可供RC框架结构抗震设计参考。

THE EFFECT OF MOMENT AMPLIFICATION FACTORS ON THE REALIZATION OF STRONG COLUMN-WEAK BEAM

In order to explore the effect of different moment amplification factors on the realization of ‘strong column-weak beam'.Nine reinforced concrete (RC) frame structure models with different moment amplification factors are simulated in the finite element software of ABAQUS.With the method of Elastic-plastic Dynamic Time-history Analysis,the story drift and plastic-hinge with different moment amplification factors are obtained and analyzed.The results show that:with the increase of moment amplification factors ηc,the maximum story drift decreased significantly,but stay stable when ηc reached to a certain value.The increase of moment amplification factors changes the failure form of nodes,and the difficulty of the realization of strong column-weak beam is different in different nodes and different stories.The corner joints and edge joints in the direction of ground motion is easier to produce strong column-weak beam-type nodes than the mid nodes and the edge joints perpendicular to the direction of ground motion.The top story is easy to produce strong column-weak beam nodes than the bottom story and the middle stories.The results can be referenced by the seismic design of RC frame structures.