受压支撑屈曲后剩余承载能力探讨

DISCUSSION ON THE REMAINING BEARING CAPACITY OF COMPRESSIVE BRACES AFTER BUCKLING

为考察受压支撑屈曲之后的剩余承载力,按照受压支撑屈曲之后还有70%剩余承载能力的假设,设计了一缩尺人字形中心支撑钢框架试件,并进行了推覆试验研究,在经历相当于结构高度1/30的顶点位移变形下,横梁并未出现明显破坏。然后分别采用SAP和ANSYS有限元程序对试验进行有限元模拟,通过SAP中塑性铰的参数设置以及ANSYS中受压支撑屈曲之后轴力的提取发现,受压支撑屈曲之后的剩余承载能力约为70%。最后采用ANSYS有限元程序分别对一人字形和V形中心支撑钢框架进行大震作用下的弹塑性时程分析,通过提取大震下受压支撑屈曲之后的轴力,进一步证实了受压支撑屈曲之后的剩余承载能力约为70%。

In order to research the remaining bearing capacity of a compressive brace after buckling,a reduced scale inverted V-CBSF was designed in this paper,according to the hypothesis that a compressive brace would remain 70% of the bearing capacity after buckling,and a pushover test was carried out.When the roof displacement reached at 1 /30 of the structure height,there was not obvious destroy on the beams.Then SAP program and ANSYS program were respectively adopted to simulate the test.Through the parameter setting of the plastic hinge in SAP and the axial force extracting of the compressive braces after buckling in ANSYS,it was discovered that the remained bearing capacity of compressive braces after buckling was about 70%.At last,ANSYS program was adopted to carry on elastic-plastic time-history analysis on an inverted V-CBSF and a V-CBSF under rarely occurred earthquake.Through extracting the axial force of the compressive braces after buckling,it was verified that the remained bearing capacity of compressive braces after buckling was about 70%.