门字型输电塔风振响应分析及风振系数的确定

The wind-induced response analysis and the wind vibration coefficient determination of door-type transmission towers

门字型塔是一种综合性能比较好的钻越塔,风荷载对这种高柔结构的影响很大,但实际设计中风振系数按规范统一取值不是很合理,且取值较大,偏于保守。故本文针对门字型输电塔在脉动风作用下的响应、风振系数的求法及合理取值进行专门研究。主要建立了门字型塔ANSYS有限元模型,进行了模态分析;以Davenport风速谱为脉动风功率自谱,应用AR法编制程序顺风模拟了风荷载时程曲线,将由模拟风计算出的风载加载至门字型塔各塔段上对其进行动力时程分析,计算了风振系数并与高耸结构设计规范值进行了比较。研究结果表明:在风载作用下,塔身和横担均会产生较为明显的动力响应;塔身、横担风振系数可取均值,分别为1.39、1.59;规范计算得到的风振系数和本文时程分析得到的风振系数变化规律基本接近,但规范取值较大。

The door-type tower is a kind of tower with better comprehensive performance.The impact of wind load on the high soft structure is very big,but during the actual design the vibration coefficient according to the code is not very reasonable.The value is bigger and conservative,so the dynamic properties of door-type towers are systematically investigated in this paper,including the response under the action of pulsating wind,the method of the wind vibration coefficient and its reasonable value range.A finite element model of the door-type tower is established using ANYSYS software,based on which the modal analysis is carried out.After imposing Davenport wind speed spectrum as the pulsating wind power self-spectrum,the time history curve of wind load is simulated using AR method.The wind load calculated above is then loaded on each section of the tower,and the corresponding dynamic time history analysis is finished.Finally,the wind vibration coefficient is obtained and compared with the one obtained by the code.It reveals that the wind load has a great influence on the dynamic responses of the tower body and the cross arm,and their average wind vibration coefficients are 1.39 and 1.59,respectively.The wind vibration coefficients calculated in present paper,as well as their variation tendencies,are consistent with that obtained by the code,while the latter value is bigger.