钢筋混凝土框架结构地震失效模式的搜索与改善

Search and improvement for failure modes of RC frame structures under earthquake

为了改善钢筋混凝土框架结构的抗震性能,利用OpenSees软件建立了一个十层三跨的钢筋混凝土框架纤维模型.首先,对比分析了现浇楼板效应对结构抗震性能的影响.结果表明,现浇楼板的存在可增大柱的转动,减小梁的转动,削弱设计时"强柱弱梁"的效果,从而改变了梁与柱达到屈服状态和极限状态的先后顺序.然后,根据结构失效准则,利用Pushover方法搜索出结构地震失效模式.最后,采用3种不同的改善方案对结构进行重新设计,通过加强局部构件来改善结构地震失效模式.研究分析表明,改善结构的不同部位能提高结构的弹塑性刚度和延性,改变地震失效模式,提高抗震性能.结构地震失效模式的搜索与改善能有效揭示建筑结构地震弹塑性发展和破坏倒塌规律,为建立结构整体抗震能力分析理论提供依据.

In order to improve the seismic performance of reinforced concrete(RC) frame structures,a ten-storey three-bay reinforced concrete frame fiber model is established with OpenSees.First,the effect of casting slab on the seismic performance of structures is analyzed.The results show that the existence of casting slab can increase column rotation,reduce beam rotation,lower the effect of 'strong column-weak beam' and change the order of the column and the beam to the yield state or the limit state.Then,according to the failure criterion,the failure modes of structures under earthquake can be searched out using pushover procedure.Finally,the structures are re-designed by three different improvement methods and the local structures are strengthened to improve the seismic failure modes.The research and analysis results show that improving the different parts of the structures can increase the elastic-plastic stiffness and the ductility,change the seismic failure modes,and improve the seismic performance.The search and improvement of the failure modes of the structures under earthquake can reveal the rule of the seismic elastoplastic development and collapse modes,which is contributed to the theory of integral seismic performance of structures.