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窄基塔作为风敏感结构,风荷载常常是其主控因素,而现有杆塔规范中无法获取窄基塔风振系数。为解决这一问题,本文以某一110kV直线型窄基角钢塔为工程背景,利用ANSYS建立有限元模型进行数值仿真计算,获得结构自振动力特性。在考虑节点风荷载空间相关性的基础上,利用Davenport谱对结构风荷载进行了准确模拟。结合动力时程计算方式对结构进行风振响应分析,计算得到窄基塔的风振系数,并与现行杆塔规范进行比较。研究表明,窄基塔风振系数随塔高增加而增大,在横担处出现突变。模拟得到窄基塔各段风振系数与规范值相差20%左右,塔腿及横担处相差更大。最后,基于动力时程计算结果提出了工程适用的窄基塔风振系数简化计算公式,为窄基塔的大范围使用提供便利。
As a wind-sensitive structure, narrow-base tower wind load is often the main control factor, while the narrow-tower wind-induced vibration coefficient can not be obtained in the existing tower code. In order to solve this problem, in this paper, a 110kV linear narrow-angle steel tower is taken as the engineering background. ANSYS is used to establish the finite element model for numerical simulation and to obtain the structural self-vibration dynamic characteristics. Based on the spatial correlation of node wind load, Davenport spectrum is used to simulate wind load effectively. The wind-induced vibration response of the structure was analyzed with the dynamic time-history calculation method, and the wind-induced vibration coefficient of the narrow-base tower was calculated and compared with the existing tower code. The research shows that the wind-induced vibration coefficient of narrow-base tower increases with the increase of tower height and changes suddenly at the cross-arm. The simulation results show that the wind-induced vibration coefficient of each section of the narrow-base tower is about 20% different from the normative value, and the difference between the tower legs and the cross-arm is larger. Finally, based on the calculation results of dynamic time history, a simplified calculation formula of wind-induced vibration coefficient of narrow base tower applied to the project is proposed, which is convenient for the wide-area use of narrow-base tower.