目前防屈曲支撑在大跨高层钢框架结构中应用广泛,其形式复杂多样,性能良莠不齐。为研究低屈服点全钢防屈曲支撑产品的抗震性能,对日本住金关西工业株式会社的4个低屈服点防屈曲支撑构件进行拉压往复加载试验研究,试验测定各试件的轴力和轴向相对位移曲线,结果显示试件均以加劲肋焊缝或芯材的超低周疲劳断裂为破坏模式,试件滞回曲线饱满,无捏拢退化现象。分析表明,此类构件能防止芯材在屈服前发生压曲,充分发挥低屈服点钢材延性好的优势。试件在循环荷载作用下,强化特征明显,强化后的应力能达到初始应力的2—4倍。该类试件在往复荷载下等效黏性阻尼比较大,具有良好的塑性变形能力和耗能能力。
Nowadays, the buckling-restrained braces with various forms and performances have been widely used in large-span and high-rise steel structures. To study the seismic behavior of buckling-restrained braces with low yield point, four specimens produced by a Japanese company--Sumikin Kansai Industries Co., Ltd. were tested under cyclic loading, and the corresponding load-displacement curves were recorded. Test results showed that all specimens failed due to the fatigue fracture of the stiffener weld or steel core, and hysteresis curves of all specimens were full without degradation or pinching. It is known from the analysis that such components could prevent their buckling before the yielding of steel core with the ductility of low yield point steel developed sufficiently. Under the cyclic loading, the hardening characteristics of specimens were remarkable with hardened stress as 2 -4 times of initial stress. Besides, under cyclic loading, the equivalent viscous damping ratio was large so that such specimens may possess good capacities in plastic deformation and energy dissipation.