考虑SSI效应的特高压输电塔风致响应试验

为了研究风荷载作用下输电塔-基础-地基耦合效应(SSI效应)对输电塔风致响应的影响,以一座特高压输电塔-基础-地基体系为例,按照离散刚度法设计其气弹模型,采用一个刚性质量块来模拟基础,U型弹簧和阻尼器来模拟地基,对气弹模型进行风洞试验,并研究地基阻尼和刚度对输电塔结构风致响应的影响规律。研究表明:1)考虑SSI效应后,模型的振动衰减要慢于刚性地基模型;同时,随着地基刚度的减小,模型的综合刚度减少且自振周期增大;2)地基刚度的减小会使上部结构位移和加速度响应逐渐增大,对塔脚反力基本没有影响;随着地基阻尼的增大,塔身加速度逐渐减小,但位移和塔脚反力几乎保持不变。因此,在进行输电塔结构设计时应考虑SSI效应的影响。

Wind tunnel test of UHV transmission tower considering SSI interaction

In order to study the influence of transmission tower-foundation-bed coupling effect (SSI interaction) on wind-induced response of transmission tower under wind load, an UHV transmission tower-foundation-bed system is taken as an example to design its aeroelastic model according to discrete stiffness method with a rigid mass block used to simulate the foundation, and U-spring and damper used to simulate the bed to test the aeroelastic model in wind tunnel. The influence of foundation damping and stiffness on wind-induced response of transmission tower structure is also studied. The experimental results show that: 1) with SSI interaction taken into account, the vibration attenuation of the model is slower than that of the rigid foundation model; with the decrease of the foundation stiffness, the comprehensive stiffness of the model decreases and the natural vibration period increases; 2) the reduction of the foundation stiffness will gradually lead to greater displacement and acceleration response of the superstructure, but have little effect on the reaction force of the tower foot; with the increase of the foundation damping, the acceleration of the tower body decreases gradually, but the displacement and the reaction force of the tower foot almost remain unchanged. In conclusion, the influence of SSI interaction should be considered in the design of transmission tower structure.