随机初始几何缺陷对柱列支撑受力的影响

INFLUENCE OF THE INITIAL RANDOM IMPERFECTION ON THE HORIZONTAL INTER-COLUMN BRACING FORCES

采用蒙特卡罗方法,研究了柱子和水平撑杆初始几何缺陷的随机遇合对柱列支撑受力的有利影响。应用有限元程序ANSYS对带有不同初始几何缺陷分布的柱列纵向支撑体系进行了大量的仿真分析,得到了柱列纵向支撑体系的四种失稳模式;通过概率统计得到柱中水平撑杆所受内力的概率密度函数,确定了可用于实际工程设计的支撑力的大小。结果表明:柱子和水平撑杆初始几何缺陷的随机遇合作用导致柱中水平撑杆受压或拉力的随机性,降低了支撑力,比《钢结构设计规范》(GB50017-2003)中柱列支撑设计公式算得的支撑力小许多。

A large number of simulation analyses for the column-bracing systems with different distributions of the initial imperfections have been conducted by the ANSYS program, in which random combination of the initial imperfections between columns and braces is considered by the Monte Carlo method. According to the analysis results, four kinds of buckling modes of column-bracing system have been found, probability density function of the bracing force are proposed through probability statistics, and the design bracing forces are also obtained. The results indicate that the random combination of the initial imperfections between columns and bracing bars leads to the randomness of the bracing bars in compression or in tension, so that the design bracing force can be reduced. The above design bracing force is much smaller than that proposed by the ＂Code for design of steel structures＂ （GB 50017）.