一种四角钢组合约束型防屈曲支撑的外围约束比取值研究

STUDY ON THE RESTRAIN RATIO OF A FOUR-ANGLE ASSEMBLED STEEL BUCKLING-RESTRAINED BRACE

与传统的外围整体式防屈曲支撑相比,装配式组合防屈曲支撑由于具有独特的构造特点,故其设计理论更具复杂性。该文针对一种四角钢组合约束型防屈曲支撑,基于对其内核构件与外围约束构件之间相互作用机制的深入认识,提出了其稳定性设计方法。首先,针对这种四角钢组合约束型防屈曲支撑,基于连续连杆法提出了一种外围约束刚度的简化计算方法。然后,在构件发生单向变形的假定条件下,通过对外围约束构件受力状态的分析,推导出其约束比设计计算公式。在此基础上,再考虑构件发生双向变形的情况,考虑次弯曲方向变形对外围约束构件受力所带来的影响,进一步补充完善了约束比设计计算理论。通过该文提出的约束比限值进行此类装配式组合防屈曲支撑的设计,可保证外围约束构件的整体稳定性与局部稳定性均能满足要求。

Compared with traditional bucking-restrained brace （BRB）, the assembled buckling-restrained brace （ABRB） possesses a more complicated design theory due to its special composition. Based on the understanding of the interaction between the core and the outer restraining components, this paper presents a design method for the stability verification for a four-angle ABRB. Firstly, by using a continuum method, a simplified method to determine the restrain stiffness of the outer restraining components is given. Then with the assumption that only one-flexural-direction displacement is produced, the limit value of the restrain ratio of a four-angle ABRB is derived based on the understanding to the stress state on the outer restraining angle steels. Based on the above conclusions, a method to determine the restrain ratio is further improved by taking the stresses brought by the flexural displacement in the second direction into account, which can assure both the overall and local stability of the ABRB.