格构式塔架三维动力风荷载的风洞试验研究

The investigation of 3-D dynamic wind loads on lattice towers by wind tunnel test

通过底座天平测力风洞试验,测量了三种典型的格构式塔架(输电塔、通讯塔和电视塔)的顺风向、横风向和扭转向动力风荷载。由于模型本身的质量不够轻、刚度不够大,一阶共振力的影响不可忽视,本文作者推导了消除模型一阶共振影响的实用公式,进而得到格构式塔架顺、横、扭三维广义荷载谱和均方根广义力系数。最后,本文分析了这三种格构式塔架的动力风荷载特征,得到了几点重要的结论。

The along-wind, across-wind as well as torsional dynamic wind loads on the models of three kinds of lattice towers are investigated using base balance technique in a boundary layer wind tunnel. The models are not light and rigid enough so that the fundamental frequencies in the directions of the principal axes of the models are still in or near the frequency range of the spectra of wind loads on lattice towers. In order to clear contaminations to the spectra of wind loads induced by model resonance, special formulae were deduced to acquire the generalized force spectra of the first mode of the models in along-wind, across-wind and torsional directions. The RMS generalized force coefficients are also obtained by removing the contributions of model resonance. Finally, the characteristics of the 3-D dynamic wind loads on the three kinds of lattice towers are analyzed, and some conclusions are obtained.