改进型双钢管约束屈曲支撑试验研究

Experimental study of improved double-tube buckling restrained braces

为提高双钢管约束屈曲支撑内核的抗侧刚度,在内核钢管上增设接触环,形成带接触环的改进型双钢管约束屈曲支撑。通过对5个不同构造的改进型双钢管约束屈曲支撑试件进行轴向单调加载、轴向低周往复加载试验,研究该类型约束屈曲支撑的承载能力、延性与耗能性能;分析外套钢管刚度、双管间隙大小、内核钢管长细比等参数对该约束屈曲支撑性能的影响。结果表明:该类型支撑受压时能够屈服而不屈曲,延性良好且滞回曲线饱满,具有良好的耗能能力;外套钢管的刚度和其与内核钢管间隙大小对该支撑的性能影响较大;试件骨架曲线均经历了弹性与弹塑性阶段,其恢复力模型可采用三折线或两折线模型。

In order to improve the behavior of double-tube buckling restrained braces,it is proposed to set one or several contact rings in the inner tube of the brace so as to provide a lateral constraint for the inner tube. Five specimens of double-tube buckling restrained braces with contact ring were tested under monotonic axial loading and low-cycle reversed axial loading. The load carrying capacity,ductility and energy dissipation of the double-tube buckling restrained brace specimens were analyzed based on the experimental results. The influences of stiffness of outer tube,clearance between inner tube and outer tube and slenderness ratio of inner tube on the behavior of the braces were studied. The results indicate the improved double-tube buckling restrained braces can yield rather than buckling under axial compressive load. The ductility is good and the hysteretic curves are plump,meaning the braces possess well energy dissipation capacity. The stiffness of outer tube and clearance between inner tube and outer tube have great influence on the behavior of improved double-tube buckling restrained braces. The skeleton curves of the braces include elastic stage and elasto-plastic stage,and the trilinear or bilinear restoring force model is put forward.