地震作用下钢筋混凝土框架结构防倒塌的判别

在地震作用下保证钢筋混凝土框架结构耗能最大化，同时保证在弹塑性变形条件下大震不倒，对框架结构意义重大。基于功能原理，对框架结构在水平地震作用下达到最大弹塑性位移时的2种变形破坏模式柱铰机制和梁铰机制进行分析，给出结构倒塌指标Ks的下限值和防倒塌的评估判别式，通过算例和实例对规范中框架结构防倒塌的相关要求进行了计算验证。结果显示，现行抗震规范对罕遇地震作用下钢筋混凝土框架结构变形控制值是略偏保守的。

Evaluation of R C frame structure to avoid collapse subjected to earthquakes

It is the great significance to ensure maximum energy consumption of the R C frame structure subjected to earthquakes and to prevent structure from collapse under the elastic-plastic deformation.Based on Workenergy principle,two kinds of collapse deformation mode column plastic hinge mechanism and beam plastic hinge mechanism for R C frame structure are analyzed,which have achieved limit deformation prescribed by code.A minimum collapse index K_S and an assessment formular of avoiding collapse are given.Through calculating examples the relevant requirements in current code for seismic design of buildings are checked.The results showed that the structure deformation limit value of R C framework subject to severe seismic action is still a little bit conservative.