防屈曲支撑内核单元特性分析与设计理论研究

Research on the characteristics and design theory for the core unit of buckling-restrained brace

根据芯材多波屈曲理论并基于边缘屈服准则,考虑芯材初弯曲以及外包钢刚度,通过理论推导出防屈曲支撑间隙值以及边缘屈服极限应力通用计算公式,分别针对"十字型"和"一字型"芯材截面,针对初弯曲大小、屈曲半波数、芯材长度、芯材宽度和芯材厚度进行影响性分析.根据边缘屈服极限应力增加值推导出屈曲半波数估计值并利用约束比概念提出新的外包钢最小约束刚度.结果表明,文章提出的防屈曲支撑设计公式可以合理解释实验和有限元模拟结果,为防屈曲支撑的设计提供理论依据.

Based on the core＇ s multi-wave buckling theory and margin yield criterion, the formula of the opti- mum gap value and the margin yield limit stress are derived after taking the initial bending of the cores and the stiffness of encased steel into consideration. Targeted on the linearshape and cruciformshape, influence analysis is made on initial bending, half waves, core＇ s length, width and thickness. The half-wave number is computed by taking advantage of the reduction of the limit stress＇ s increment. Finally, the minimum required stiffness of encased steel is proposed by means of improved calculating formula. As the result shows, the BRB design for- mula in this paper can reasonably explain the experiment and finite element data, providing theoretic foundation to BRB design.