【摘要】 根据Jezek的思想,假定杆件的平衡挠度曲线为半波正弦曲线,材料的本构关系符合理想弹塑性模型。对于有初弯曲和初偏心等初始缺陷的杆件,可以将杆件的长细比λ表示成截面屈服区高度hx的函数。针对箱形截面特性,结合中国铁路桥梁钢结构设计规范,通过求上述函数的极值得到两端简支无初始残余应力箱形截面杆件压溃荷载的近似计算公式;并通过展开级数,得到等边箱形截面杆件的压溃荷载计算公式。算例表明:用这种近似计算公式求解压杆的极限荷载时,无需对截面划分单元,工作量少,具有非常高的计算效率和较好的计算精度,适合大型桥梁初步设计阶段近似确定杆件的压溃荷载。更多还原

【Abstract】 For an imperfect column with initial geometric imperfection,initial eccentric loading imperfection and without initial residual stress in the section,the balance flexibility curve of it can be assumed as a half-sinusoid curve and the material of the column as an elastic-perfectly plastic body.Based on Jezek’s theory,the slenderness-ratio of the column λ was written as function of hx: height of yield area in the section.Analyzing the dimensions of the box-section with the Chinese Design Code for Railway Bridge Steel Structure,then the formulas for approximate calculation on ultimate carrying capacity of a simply-supported column with box section could be obtained by solving the extremeness value of the function.The formula used for column with four equal sides of its box-section was also studied by expanding the series.The numerical example demonstrates that the formals need few workload and no mesh,have also extraordinary high frequency and satisfied accuracy in calculation,so they are suitable for approximately getting the ultimate carrying capacity of the column in the preliminary bridge design stage.更多还原