新型防屈曲耗能支撑设计原理与性能研究

A study on the design principle and performance of a new type of Buckling-Resistant Brace

介绍防屈曲耗能支撑的构成和工作原理,归纳防屈曲耗能支撑的类型,分析现有防屈曲耗能支撑存在的不足,提出"核心单元局部削弱相当于其他部分加强"的新型防屈曲耗能支撑设计思想,给出"开孔式"和"开槽式"两种新型防屈曲耗能支撑设计方案。设计新型开孔式三重钢管防屈曲耗能支撑与普通三重钢管防屈曲耗能支撑模型,通过对这两种模型的循环加载试验,对比研究两者的性能差异。试验研究结果表明:开孔式防屈曲耗能支撑滞回曲线稳定、饱满,具有良好的耗能性能;在相同条件下,开孔式防屈曲耗能支撑的耗能能力、等效黏滞阻尼比、耗能系数与普通三重钢管防屈曲耗能支撑相比差别不大,但是开孔式防屈曲耗能支撑具有定点屈服的功能,即屈服位置可以预先设定;能同时实现由同种材料制成的核心单元具有屈服段与非屈服段,避免普通三重钢管防屈曲耗能支撑端部另需加强及加工困难等不足。证明通过"核心单元局部削弱"的方式来改进防屈曲耗能支撑性能的思想是现实可行的。

The composition and inner working of Buckling-Resistant Braces （BRBs） are introduced. The existing types of BRBs are reviewed and their shortcomings pointed out. A new design for BRBs named ＇ local weakening of core unit＇ is proposed, and two new types design methodologies, ＇ hole-type＇ and ＇ notch-type＇ , respectively, are developed. A ＇ hole-type＇ BRB specimen and traditional BRB specimen are experimentally studied through cyclic loading test. The test results indicate that the ＇ hole-type＇ BRBs exhibit a steady and plump hysteretic relationship and good energy-dissipation performance. Under the same conditions, there are not obvious differences in energy-dissipation capacities, equivalent viscous damping ratios and energy-dissipation coefficients between the ＇ hole-type＇ BRBs and the ordinary triple-steel- tube BRBs. However, the ＇ hole-type＇ BRBs may yield at certain prescribed point. The core pipes are made of the same type of material in the yielding region and non-yielding region, and such characteristics overcomes the shortcomings of the ordinary triple-steel-tube BRBs, for which both ends need to be enhanced and the fabrication and construction processes are complicated. The results show that it is practicable to improve the performance of the BRBs by the means of ＇local weakening at the core unit＇.