全钢型分离式防屈曲支撑的约束比取值研究  

Restrain ratio of all-steel core-separated buckling-restrained braces

作　　者：郭彦林[1] 张博浩[1] 朱博莉[2] 

机构地区：[1]清华大学土木工程系,北京100084 [2]西安交通大学人居环境与建筑工程学院,陕西西安710049

出　　处：《建筑结构学报》2015年第11期133-141,共9页Journal of Building Structures

基　　金：国家自然科学基金项目(51178243);清华大学自主科研计划(2012Z10134)

摘　　要：全钢型分离式防屈曲支撑,在两端铰接时,两个内核构件独立伸出外围约束构件后端部通过肋板连接,形成较强的端部接头,由于这种端部构造以及内核之间有一定距离,内核与外围约束构件之间相关作用较复杂。鉴于传统的约束比限值计算公式不再适用,对其约束比取值进行了研究。考虑支撑整体几何初始缺陷的影响,依据其失稳机理将其侧向变形分解为正弦型变形和余弦型变形,分别计算两种变形下的跨中侧向变形,按计算所得比例组合得到实际的跨中侧向变形,所得的轴向荷载与跨中侧向变形曲线与有限元分析结果吻合较好。利用外围约束构件截面最大受弯承载力不小于考虑二阶效应跨中弯矩的控制条件,并在常见设计参数范围内进行有限元分析与拟合,得到实用的约束比限值计算式。有限元分析结果表明,该方法可用于预测分离式防屈曲支撑在静力单调轴压作用下的受力性能。All-steel two core-separated buckling-restrained braces（ CSBRBs） is proposed and their behavior and design method are studied. In a pin-ended CSBRB,projections of two cores longitudinally beyond restraining members are welded with an end plate,forming a reliable end connection. The interaction between cores and restraining members is more complex due to this kind of end connection detail and two cores spacing a distance. The method to determine the minimum restraining ratio of conventional buckling-restrained braces is not suitable for CSBRBs. The lateral displacement of a CSBRB is divided into two parts,i. e.,the displacement corresponding to the sinusoidal mode and that corresponding to the cosine mode. And the displacements in the middle of the CSBRB corresponding to two modes are calculated respectively,considering the influence of global initial geometric imperfections. Then the displacement in the middle of the CSBRB is obtained by combining two lateral deformation modes and verified by the finite element numerical analysis. Based on the principle that the lateral bending bearing capacity of restraining members should exceed the maximum moment in the middle of the CSBRB when the axial force in the cores reaches to full sectional yielding,a simplified method to determine the threshold of the restrain ratios is proposed by FE analysis and fitting solution,which can be used to predict the overall stability performance of CSBRBs under static monotonic compressive loads.

关 键 词：全钢型支撑 分离式防屈曲支撑 有限元分析 约束比 设计方法 

分 类 号：TU352.102[建筑科学—结构工程]