基于能量平衡的梁柱刚接防屈曲支撑钢框架设计方法

Design method of buckling-restrained brace frame based on energy balance

针对梁柱刚接的防屈曲支撑钢框架,根据能量平衡的概念提出基于能量的抗震设计方法,使结构在罕遇地震作用下满足给定的目标位移。设计方法以钢框架与防屈曲支撑在目标位移下耗散的能量之和等于地震输入能量为准则进行能量分配。地震输入能量以原钢框架的地震输入能量为基准,计入结构周期和延性变化的影响进行调整后得到,并以结构在位移幅值下循环1周耗能作为总耗能。建立防屈曲支撑的耗能需求曲线和目标位移下的耗能能力曲线,求得防屈曲支撑的截面面积。应用此方法设计3跨5层的防屈曲支撑钢框架结构,采用ANSYS软件建立有限元模型,对所设计的钢框架结构进行罕遇地震作用下的时程分析,结果表明:应用此方法设计的梁柱刚接防屈曲支撑框架在地震作用下最大层间位移角与给定的设计目标较为一致,所设计的结构安全可靠。

A design method for buckling restrained brace frames（BRBFs） was proposed based on energy concept.The input seismic energy was assumed to be dissipated by the steel frame and BRBs at the target displacement.On the basis of the input energy of the frame without BRBs,the input energy of BRBFs was obtained by adjusting its structural period and ductility.The energy dissipated in one cycle at the positive and negative maximum displacements was taken as the total dissipated energy under an earthquake.The required energy dissipation curve and the energy dissipation curve at the target displacement were established to obtain the area of the section of the BRB.A three-bay and five-story BRBF was designed based on the proposed method.And a finite element model was established using ANSYS.The results of the nonlinear time history analysis for the structure indicate the maximum inter-story drift agrees well with the target value,and the designed structure is safe.