钢筋混凝土框架柱端弯矩增大系数初探

Initial Discussion about the Moment Amplification Factor of Reinforced Concrete Frame Columns

四川汶川地震中,房屋典型的震害表现为,一些钢筋混凝土框架结构柱端出现了严重的塑性铰,而梁端震害反而较轻,"强柱弱梁"的抗震设计目标在混凝土框架中未能实现。本文首先总结了我国现行规范中关于"强柱弱梁"的相关规定及存在的问题,然后分析不同柱端弯矩增大系数对框架结构塑性铰分布的影响,结果表明,当柱端弯矩增大系数取为1.7时能有效地实现"强柱弱梁"。

In the Wenchuan Earthquake,earthquake damage about houses typically expressed as a number of reinforced concrete frame structures are damaged seriously with plastic hinges occurred at column ends rather than beam ends,which is significantly different to the failure mode expected in the seismic design of strong column weak beam.In this paper,the relevant provisions on Chinese existing design code about ＂strong column-weak beam＂ and the existing problems are presented,and then the effect of different moment amplification factor of column on distribution of plastic hinges is analyzed.Analysis shows that when the moment amplification factor is 1.7 can effective achieve＂strong column weak beam＂.