Frequency Domain Analysis of Alongwind Response and Study of Wind Loads for Transmission Tower Subjected to Downbursts
Frequency Domain Analysis of Alongwind Response and Study of Wind Loads for Transmission Tower Subjected to Downbursts
复制标题
下击暴流输电塔顺风响应频域分析及风荷载研究
DOI：
10.3390/buildings12020148
复制
发表时间：
2022-01
期刊：
影响因子：
3.8
通讯作者：
Yan Li
中科院分区：
文献类型：
--
作者：
Yongli Zhong;Shun Li;Weichen Jin;Zhitao Yan;Xinpeng Liu;Yan Li
下击暴流是导致输电塔故障的高强度风之一。目前，输电塔线体系在下击暴流风荷载作用下的规范不能满足设计要求。本文基于单自由度系统非平稳风的频域模态分析理论，推导了下击暴流风荷载作用下输电塔的背景分量和共振分量的计算公式。讨论了结构动力特性、阻尼比和平均风速垂直廓线对结构动力响应的影响。根据最大响应得到等效静力风荷载，并与时域有限元法进行比较。这些公式的应用，从霍姆斯的经验模型和现场记录的后翼下沉气流（RFD）的情况下解决。结果表明，本文公式计算的最大响应值与模态分解法和有限元动力分析法计算的最大响应值吻合较好。与ASCE规范推荐的下击暴流荷载计算结果相比，基于最大反应的ESWL计算结果更接近有限元计算结果。该框架可用于辅助考虑下击暴流风荷载的输电塔抗风设计。
Downburst is one of the high-intensity winds that cause transmission tower failures. The regulations of transmission tower-line systems under downburst wind loads cannot meet the design requirements at present. In this paper, the calculation formulas of the background and resonant components of transmission tower under downburst wind loads are obtained, based on the modal analysis theory of non-stationary wind for the single-degree-of-freedom system in the frequency domain. The effects of structural dynamic characteristics, damping ratio, and mean wind speed vertical profile on dynamic effect on structural response are discussed. Then the equivalent static wind load (ESWL) is obtained according to the maximum response and compared with the finite element method (FEM) in the time domain. Applications of these formulas are addressed to the cases from the empirical model of Holmes and field record of a rear flank downdraft (RFD). The results show that the maximum responses obtained by the current formulas match well with those from the modal decomposition method and dynamic analysis with FEM. The internal forces of tower members calculated by ESWL based on maximum response are closer to the results from FEM than those calculated by downburst loads recommended in ASCE guidelines. The presented framework can be used to assist the wind-resistant design of transmission towers considering downburst wind load.