两端铰接防屈曲支撑的受力性能及设计方法

Behavior and design method of pinned-pinned buckling-restrained brace

在两端铰接的防屈曲支撑中,内核构件的端部构造不仅影响端部构件段的承载力,而且影响支撑的整体受力性能。通过理论推导与有限元分析,对内核构件端部具有外伸屈服段、加强段的两端铰接防屈曲支撑的破坏形式以及整体受力性能进行了研究。研究表明:在轴压力作用下,内核构件外伸屈服段、加强段会发生侧向变形,进而对外围约束构件产生附加偏心距,对外围约束构件的受力不利;当内核构件外伸段过长时,外伸段会发生弯折破坏。对端部局部内核构件段隔离体作受力分析,可得到一种简化计算模型,采用迭代算法,可偏于安全地确定内核构件外伸段变形对外围约束构件端部产生的附加偏心距。考虑附加偏心距的影响,给出了两端铰接防屈曲支撑的整体设计方法。

In buckling-restrained braces（BRBs） with pinned joints,the core component near the ends have influence on both the capacity of the core segments near the ends and the overall behavior of the BRB.Based on theoretical and numerical analysis,this paper discusses the failure modes and the overall behaviors of pinned-pinned BRBs with unsupported yielding segments and strengthened segments near the ends.It is found that the unsupported yielding segments and strengthened segments of the core will bend under axial pressure,which will induce additional eccentricities at the ends of the restraining part,making the stress state more unfavorable.If the unsupported segment of the core is too long,failure may occur in the segment with too much bending.By taking the core segments near the ends out as a free body,a simplified model was obtained.Using an iterative method cooperatively,the simplified model can approximately determine the eccentricities added at the two ends of restraining parts.Finally an overall stability design method that can take the additional eccentricities into account is given.