框架-支撑芯筒结构体系的耗能机制研究

Research on Energy Dissipation Mechanism of Frame Braces-Tube Structure

为研究框架-支撑芯筒结构在罕遇地震下的耗能机制,对框架-支撑芯筒结构进行弹塑性时程分析,观察结构的耗能分布,并与框架-核心筒结构进行对比,分析设置屈曲约束支撑(BRB)后框架-支撑芯筒结构体系耗能的变化。结果表明:(1)两种结构体系耗能的不同之处在于框架-核心筒结构塑性耗能主要集中在连梁上,而框架-核心筒结构塑性耗能分散在各类构件上,由于钢支撑在罕遇地震下不易屈服,耗能能力未充分发挥。(2)采用BRB等截面替换支撑芯筒的钢支撑,框架-支撑芯筒结构的耗能机制基本保持不变。(3)适当缩小BRB的芯材截面,降低BRB的屈服力,不仅能够降低总体能量输入,而且能够将提高BRB的耗能占比,降低其他构件的塑性耗能,有效地保护了其他构件。可见,理想的框架-支撑芯筒结构宜设置部分或全部采用BRB替代钢支撑。

To study the energy dissipation mechanism of frame braces-tube structure under rare earthquake,the elastic-plastic time history of frame braces-tube structure and frame-corewall structure are carried out. The differences of energy dissipation are observed. A comparison with frame braces-tube structure with BRB is complemented. It is found that:(1)The energy dissipation of frame-corewall structure depends on coupling beam,while frame braces-tube structure depends on braces yielding. But the energy dissipation capacity of braces is not fully used due to its high yield strength.(2)The energy dissipation mechanism of frame bracestube structure is unchanged when the braces are replaced by equal section BRB.(3)The energy dissipation capacity of BRBs is increase,and other components are decreased when the cross-section area of BRB is reduced. Therefore,the ideal braces-tube structure had better to use BRB to replace steel braces partly or completely.