钢管-角钢组合输电塔杆件体型系数及背风面风荷载折减系数的风洞试验研究
2021-09-13牛华伟,刘淦彬,杨风利,张宏杰
牛华伟,刘淦彬,杨风利,张宏杰



摘 要:对钢管-角钢组合输电塔一类的风敏感结构,其各杆件的体型系数及折减系数是该结构抗风设计中重要的风荷载参数. 以500 kV和110 kV输电塔为工程背景,首先設计缩尺比分别为1 ∶ 8.5的塔身和1 ∶ 2.5横担刚性节段模型,然后在3个不同均匀来流风速及不同风向角下进行同步测压风洞试验,得到角钢及钢管杆件的体型系数与背风面风荷载折减系数的变化规律. 并以此归纳了塔身和横担各杆件的体型系数分布及不同风向角下节段模型整体体型系数,最后将试验确定的结果与国内外相关规范值进行比较. 结果表明:来流风速对塔身和横担中的角钢体型系数几乎无影响. 在0°风向角下,塔身角钢体型系数沿塔身节段呈上小下大的变化趋势. 塔身杆件中的角钢折减系数与日本规范较吻合. 在不同雷诺数下的塔身(3.10×104~4.34×104)或横担(5.57×104~8.00×104)节段模型折减系数的差值很小. 塔身和横担节段模型阻力系数与日本规范较吻合,中国规范取值分别偏小7.2%和4.5%.
关键词:风洞试验;输电塔;塔身;横担;角钢;钢管;体型系数;遮挡效应
中图分类号:TM753;TU347 文献标志码:A
Wind Tunnel Tests on Shape Coefficient and Shielding Factor
of Members for Tubular-angle Steel Transmission Tower
NIU Huawei1?覮,LIU Ganbin1,YANG Fengli2,ZHANG Hongjie2
(1. College of Civil Engineering,Hunan University,Changsha 410082,China;
2. China Electric Power Research Institute,Beijing 100055,China)
Abstract:The shape coefficient and shielding factor of each member are important in the wind resistant design of the structure for wind sensitive structures such as tubular-angle steel transmission towers. Taking 500 kV and 110 kV transmission towers as the engineering background, the rigid section model of tower body with a scale ratio of 1 ∶ 8.5 and cross-arm with a scale ratio of 1 ∶ 2.5 are designed firstly. Then, through the wind tunnel tests on synchronous pressure measurement of the model under three different wind speeds and different wind incidence angles, the variation rules of shape coefficient and shielding factor of angle and steel pipe members are obtained. On this basis, the shape coefficient distribution of members in the tower body and cross-arm, and the shape coefficients of the section models under different wind incidence angles are summarized. Finally, the results determined by the test are compared with the relevant normative values at home and abroad. The results show that the incoming wind speed has little effect on the shape coefficients of angles in tower body and cross-arm. The shape coefficients of angles in the tower body tend to be small at the top but large at the bottom along the section of tower body under 0° incidence angle. The shielding factors of angles in tower body are consistent with that in the Japanese code JEC. In the test, the difference of the shielding factors of tower body (3.10×104~4.34×104) and cross-arm (5.57×104~8.00×104) under different Reynolds number of main materials is very small. The drag coefficients of tower body and cross-arm are consistent with that in Japanese standard, whereas the values of Chinese standard are 7.2% and 4.5% lower, respectively.
Key words:wind tunnel test;lattice towers;tower body;cross-arm;angle members;steel pipe;shape coefficient;shielding effect
输电塔由于自身独特的结构,对风荷载极其敏感,因此对于不同结构形式的输电塔风荷载计算和参数运用是必不可少的. 体型系数和背风面风荷载折减系数是输电塔风荷载中的关键参数. 近年来,钢管-角钢组合输电塔的运用越来越广泛,而对钢管-角钢组合输电塔的风荷载研究……
