输电塔不等边角钢交叉斜材稳定承载力研究

对一种输电塔常用平面节间进行了真型试验,研究了不等边角钢交叉斜材在一拉一压受力情况下的稳定承载力与破坏模式;采用ABAQUS有限元软件对不等边角钢斜材试件进行模拟,验证了有限元模型的可靠性,并进而研究了不同内力比值、钢材强度、截面规格对斜材承载力的影响规律。结果表明:试验中不等边角钢失稳模式主要为面外屈曲。当斜材处于一拉一压时,压杆承载力随拉力增加而增大;当斜材处于同时受压时,极限承载力随着两杆压力比值的增加而减小;在同时受压状态下,提高材料强度对承载力的提高不会起到显著的作用;增大肢厚或平面内和平面外肢长均能使承载力提高。基于以上分析,提出了可供参考的不等边角钢交叉斜材的计算长度修正系数,并与现有规范进行了比较。

Investigation on the Stability Bearing Capacity of Unequal Angle Steel Cross Bracing in Transmission Towers

A lattice section commonly used in transmission towers is tested to study the bearing capacity and failure modes of cross bracing under tension/compression system.The specimens are also simulated using ABAQUS software to investigate the bearing capacity under different stress states,which validated the reliability of the finite element models.The finite element analysis of unequal angle steel considering different internal force ratios,material strengths and cross-sections has been conducted.Based on the test results,out-plane buckling of cross bracing occurred during the test.When one member is in tension and the other is in compression,the stability capacity of cross bracing increases with tension.When the cross members are both in compression,the stability capacity of cross bracing decreases with compression.Under the condition of simultaneous compression,increasing the strength of material has little impact on increasing bearing capacity.If the thickness or the length of two directions increases,the bearing capacity increases.According to the results of the test and finite element analysis,the calculated length correction factor for unequal angle steel cross bracings is proposed and compared with the results according to current standards.