柔性腹杆输电塔风振特性及抗倒塌分析

Wind Vibration Characteristics and Collapse Resistance Analysis of Flexible Web Member Transmission Towers

输电塔对风十分敏感,在大风及台风作用下易发生局部破坏甚至倒塌,提升和改善输电塔抗风能力及加固改造技术一直是输电塔重要研究内容之一。对110kV输电线路典型猫头塔塔身斜材进行柔性腹杆改造,采用ANSYS软件建立该塔柔性腹杆改造前后的有限元模型。对改造前后分别进行了模态分析、静力分析,确定结构的动力特性和静力加载下塔身抗侧刚度。对改造前后的输电塔进行风振响应分析,对比其风振响应特点。最后采用弧长法对改造前后的输电塔进行倒塌分析,对比得到弹塑性极限承载能力。分析结果表明:柔性腹杆输电塔较改造前的铁塔塔身抗侧刚度有较大提升,该改造方式可有效控制风荷载作用下铁塔塔头的位移(降幅达17%);同时柔性腹杆的改造提高了在大风荷载下的输电塔极限承载能力(增幅达10%)。

Transmission towers are very sensitive to wind and are prone to local damage or even collapse under strong winds and typhoons.Enhancing and improving the wind resistance capacity of transmission towers and the reinforcement and transformation technology have always been one of important research contents of transmission towers.A flexible belly bar has been implemented to retrofit the typical cat-head tower body skew of a 110 kV transmission line.Utilizing ANSYS software,the finite elements of the transmission tower before and after being retrofitted were created.Modal analysis and static analysis were conducted to ascertain the dynamic characteristics of the structure and its lateral stiffness under static loading before and after the transformation.Wind vibration responseswere analyzed before and after the transformation.A comparative assessment was made between the wind vibration responses of the transmission tower before and after modification.Finally,collapse analyses of the transmission towers before and after being retrofitted were performed using an arc length method with comparison yielding elastic-plastic ultimate bearing capacity results.Analysis indicates a significant enhancement in lateral stiffness compared to transformation before being retrofitted conditions for the transmission tower;this transformation method effectively reduces displacement of the tower head under wind load by 17%.Additionally,modification of the flexible belly rod enhances ultimate bearing capacity under wind load by up to 10%.