少钢支撑RC框架结构的概念

THE CONCEPTION OF RC FRAME STRUCTURES WITH A FEW STEEL BRACES

震害表明,在钢筋混凝土(RC)框架结构中增设少量支撑,可以解决纯框架结构抗震防线单一、缺乏足够冗余度的问题,通过多重抗震防线,保护主体结构构件、减小建筑震害、增加结构的安全储备和防倒塌能力。我国现行规范对含有少量剪力墙的框架结构已经有了明确定义和相应的设计方法,而对于含有少量支撑的框架结构没有定义。该文以一个典型RC框架结构及三个带不同钢支撑的RC框架结构为例,基于弹性分析和弹塑性Pushover分析,借鉴少墙框架的定义方法,提出了以底层框架倾覆力矩分担率为控制指标的少钢支撑RC框架结构的定义,并通过基于IDA的结构抗倒塌易损性分析验证了少钢支撑RC框架结构相比纯框架结构的抗倒塌能力提高。

The seismic damage of reinforced concrete(RC) frame structures during earthquakes has indicated that the widely used RC frame structures are lack of sufficient redundancy under earthquake actions. The damage of RC columns in a RC frame leads to its serious damage even collapses during a strong earthquake. If few steel braces are installed, the RC frame will become multi-fortification with steel braces as its first yielding structure elements and RC frame structure elements will be protected and its damage will be delayed. As a result, its safety margin and collapse-resisting capacity will be improved. According to a RC frame structure with few shear walls,this paper proposed the new conception of a RC frame structure with few braces. A typical RC frame structure and3 RC frame structures with different braces are studied to achieve the definition of a RC frame structure with few braces based on the overturning moment carried by a frame part. With few steel braces, the collapse-resistant capacities of a RC frame structure is proved through a collapse fragility analysis based on an incremental dynamic analysis(IDA).