考虑横向支撑刚度影响的组合截面压杆稳定承载力

Stability Bearing Capacity of Built-up Section Compression Member Considering the Influence of Lateral Bracing Stiffness

在压杆中部设置横向支撑来减小其计算长度,可提高压杆稳定承载力并节约钢材。目前对此类构件的计算和试验研究较少,工程中现有的处理方法略显粗糙。因此,以三弯矩方程为基础,建立考虑横向支撑刚度和残余应力影响的方程来计算压杆承载力,并进行足尺寸构件试验(角钢规格为Q420,2L160 mm×14 mm,长细比λ=30～50)与计算结果对比,得到横向支撑与构件稳定承载力之间的关系。结果表明,考虑支撑刚度和残余应力的公式的计算值与试验值基本相符,略低于试验值;横向支撑可有效提高试件稳定承载力,但工程中现有计算方法未考虑长细比的影响,试件实际承载力与计算值偏差可达20%以上;建议的承载力公式为试验值和计算值的下限,可为此类构件设计作参考。

After the installation of lateral bracing,the effective length of column could be reduced,the stability bearing capacity and steel saving are profitted by it.Existing research focused in this area is insufficient,and the current design methods used in engineering field are not precise enough.In order to treat this problem,calculation equations were established based on the three-moment equation,and the influence of lateral bracing stiffness and residual stress were involved.A full scale test was conducted for comparing with the calculation result,and the test covered parameters Q420,2L160 mm×14 mm,and λ=30~50.The relationship between lateral bracing and stability bearing capacity of column was acquired.The test results showed that the developed calculation method matches with these results,and is slightly lower than them.Though lateral bracing could enhance stability bearing capacity evidently,the maximum discrepancy between current design method and test results is larger than 20% for the simple reason that the method does not take the slenderness ratio into account.Proposed formula is the low limit of test and calculation results,and it can be a reference for such column during designing.