钢筋混凝土框架结构屈服机制研究进展

Research progress on yield mechanism of RC frame structures

针对历年多次大地震中钢筋混凝土框架结构大多未能实现“强柱弱梁”的问题,结合20世纪80年代以来我国抗震规范历次修订的背景资料,对国内外钢筋混凝土框架结构屈服机制的研究成果以及规范相关规定的沿革情况进行综述。首先,对我国GBJ 11—1989《建筑抗震设计规范》中有关框架结构梁柱节点的研究背景及有关规定进行了介绍;其次,对21世纪以来国内外部分强震中框架结构的震害现象及特征进行概述,梳理分析了震后若干反思性研究成果,并对比分析了国内外规范的相关规定;再次,结合国内外有关RC框架结构屈服机制的最新研究动态,从微观层面的材料本构方程和宏观层面的构件物理方程进行分析,指出采用基于强度准则的能力设计方法在理论上存在明显缺陷,应基于变形(应变)破坏准则进行RC框架结构整体屈服机制的研究。鉴于目前框架结构屈服机制抗震设计方法存在的问题,提出可采用构件变形能力需求比作为指标,充分考虑构件刚度配置、结构破坏演化进程中构件刚度退化对内力重分布的影响规律等因素,从节点、构件、结构层面综合开展理论与试验研究,全面构建基于变形准则的能力设计方法。

In view of the problem that most reinforced concrete frame structures have failed to achieve'strong columns and weak beams'in many major earthquakes over the years,combined with the background information of China's seismic code revisions since the 198Os,this paper evaluates the research results of yield mechanisms of reinforced concrete frame structures at home and abroad,as well as the evolution of relevant regulations in the code.Firstly,the research background and relevant provisions of the GBJ 11-1989 about beam-column joints in frame structures are introduced.Secondly,the seismic damage phenomena and characteristics of some strong epicenter frame structures at home and abroad since the 21st century are summarized,several reflective research achievements in engineering and academia after earthquakes and relevant regulations at home and abroad are analyzed.Thirdly,based on the latest research trends on the yield mechanism of RC frame structures,the material constitutive equations at the micro level and the physical equations of components at the macro level are analyzed.Finally,it is pointed out that the capability design method based on the strength criterion has obvious defects in theory,and the overall yield mechanism of RC frame structures should be studied based on deformation failure criteria.In view of the problems existing in seismic design methods,this article proposes that the ratio of deformation capacity and demand can be used as index,which fully considers the component stiffness configuration and the influence of local stiffness degradation on internal force redistribution in the process of structural failure evolution,and theoretical and experimental research should be carried out from the node,component,and structural levels to comprehensively construct a new capacity design method based on deformation criteria.