输电塔风振系数分析

Wind-Induced Vibration Coefficient of Tranmission Towers

运用随机振动理论,考虑输电塔外形、质量突变,体型系数差异,推导了输电塔风振系数计算公式.模拟了风荷载时程,进行有限元动力时程分析,时程分析和按风振系数静力分析的对比表明:平行线路方向,修正后横担处风振系数变小,下部塔身风振系数变大.按修正后风振系数计算的内力在塔上部会比按荷载规范计算的小,而到塔底部则基本持平,按荷载规范计算偏于安全.垂直于线路方向,修正后横担处风振系数变大,塔身风振系数变小.按修正后风振系数计算的内力在塔上部会比按荷载规范计算的大,而到塔底部则基本持平,按荷载规范计算偏于危险.

Using random vibration theory, considering the clltterences ux t^a,l^L,J.-~ shape, quality distribution, shape coefficient, the wind-induced vibration coefficient expression was de- duced. Wind load time histories were simulated. Finite element analyses were carried out. The contrast be- tween the time history analysis and the static analysis showed that the modified wind-induced vibration coef- ficients of crossarm become smaller and those of tower body become bigger while the wind direction is paral- lel to the line. The inner forces of upper tower according to modified wind-induced vibration coefficients are smaller tha~ those according to the load code and the inner forces of tower base according modified wind-in- duced vibration coefficients are almost the same with those according the load code. The load code is safe. But, when the wind direction is perpendicular to the line, the modified wind-induced vibration coefficients of crossarm become bigger and those of tower body become smaller. The inner forces of upper tower according to modified wind-induced vibration coefficients are bigger than those according to the load code and the inner forces of tower base according modified wind-induced vibration coefficients are almost the same with those according the load code. The load code is dangerous.