高层钢框架结构附加屈曲约束支撑阻尼投放量的简易计算方法研究

Study of Simple Methods for Calculating Damping Amount of Buckling Restrained Brace in High-rise Steel Frames

依据建筑抗震设计规范(GB50011-2010)建立24层空间钢框架结构,分别采用等效线性化理论、能量平衡以及倍数法的设计方法计算高层钢框架结构附加屈曲约束支撑的阻尼投放量,并采用Midas/Gen软件对附加阻尼的消能减震结构进行弹塑性时程分析,考察和比较以上三种理论方法确定阻尼量的过程和附加阻尼后结构的减震效果。结果表明:1采用等效线性化理论计算时,设定参数和使用公式较多且繁琐,耗费大量时间和精力;采用倍数法计算时,"最佳倍数"的确定需要反复试算多种工况,计算量较大;2采用能量法计算时,参数和公式少、力学概念清楚、原理易懂,且减震效果最好,故认为用此方法计算阻尼投放量既有效又简便。最后给出了能保证良好消能减震效果的有效弹性刚度比和屈服力比的参考范围,为消能减震结构设计提供依据。

The damping amount of the buckling restrained brace in a 24- story steel braced frame designed in accordance with the requirements of Chinese Code for Seismic Design of Buildings is calculated by using the equivalent linearization method,energy balance method and multiplicity method. Then the elastic-plastic time history analyses of this frame are performed by using Midas / Gen software. The process of determining the damping amount of the buckling restrained brace by these three theoretical methods are investigated and compared. The results show that the equivalent linearization method includes more parameters and formula,and therefore needs more time than the others. In the multiplicity method,the best multiplicity is calculated according to several working conditions,which means that large amount of calculation is needed. The energy balance method needs less parameters and formula compared with the other two methods. It has clear mechanics concept and is easy to be understood. By using it,the ideal range of the elastic stiffness ratio and yield strength ratio,which can ensure better vibration absorption effect,is proposed for design of buckling restrained braces.