铸造十字形截面屈曲约束支撑的抗震性能试验研究

Experimental Study on the Seismic Performance of Casting Cruciform-Shaped Buckling-Restrained Brace

采用铸造工艺直接加工十字形截面核心的屈曲约束支撑(BRB,Buckling-Restrained Brace),避免在核心部件上直接施焊,可以消除焊接残余应力的影响。通过低周往复加载试验,研究了该类试件的滞回性能、骨架曲线、累积塑性变形、拉压不对称性、等效刚度等。试验结果表明,该类型的屈曲约束支撑可以避免焊接残余应力对试件抗震性能的影响,支撑试验滞回曲线饱满,具有稳定的受力特性,累积塑性变形基本达到200,且拉压不对称系数小于1.3,满足美国AISC钢结构规范的要求。由于铸造用钢有材料上的缺陷,导致试件没有获得较好的低周疲劳性能,但是对低周疲劳性能要求不高的承载型BRB仍具有一定的应用价值。

The casting cruciform-shaped buckling-restrained brace（BRB）can avoid welding at the core of the brace.This eliminates residual stress significantly during the welding process.In this paper,cyclic loading tests are conducted to study the performance of this kind of BRB including hysteresis curves,skeleton curves,cumulative plastic deformation,asymmetrical property under tension and compression,as well as equivalent stiffness of BRB.The experimental study shows this type of BRB reduces the influence of residual stress on hysteretic capacity of braces.The brace has steady mechanical property,good low-cyclic fatigue property with considerable full hysteresis curves.Also the asymmetrical factor of tension and compression is lower than 1.3,and this satisfies AISC requirement.Because of the imperfection in casting steel material,the specimens exhibit relatively poor fatigue property.However this BRB has potential value for the application where no strict fatigue property is required.