Vortex-induced oscillations of reinforced concrete chimneys and its wind tunnel studies using elastic models.

在风洞试验中模拟建筑物或结构的动力特性时，应同时满足风特性和结构的动力相似要求。模型空气密度通常等于全尺寸空气密度。因此，为了使质量比相同，模型的材料密度应等于足尺结构的材料密度。当注意力集中在某些特定的降低频率上时，G.涡共振、模型材料的弹性模量值对试验风速和模型尺寸都有一定的制约作用。感兴趣的现象的约化频率应在风洞及其设备或仪器固有的可用风速范围内实现。研究并合成了用于钢筋混凝土结构风洞模拟的新材料。选用环氧树脂作为模型的材料。钢筋混凝土的密度约为2.4g/cm^3，而环氧树脂的密度为1.2g/cm^3。由于环氧树脂的密度小于钢筋混凝土的密度，为了使质量参数一致，在溶剂中加入铁粉，然后用这种材料制作的模型对钢筋混凝土烟囱的涡激振动进行了风洞试验。将模型的动力特性与足尺试验结果进行了比较，验证了该材料的可行性，并提出了圆形截面钢筋混凝土结构的抗风设计方法。

When the dynamic behavior of buildings or structures is simulated in the wind tunnel testings, the dynamic similarity requirements both of the wind characteristics and the structures should be satisfied. The model air density is usually equal to the full-scale air density. Therefore, in order to make the mass ratio identical, the material density of the model should be equal to that of the full-scale structure. When attention is paid on some particular reduced frequencies, e. g. the vortex resonance, the value of the elastic modulus of the material of the model restricts the windspeed of testings as well as the size of the model. The interested reduced frequency of the phenomena should be realized in the available windspeed range inherent to the wind tunnel and its facilities or instruments.The new material for the wind tunnel simulations of reinforced concrete structures is investigated and composed. The Epoxy resin was selected as the stuff of the material of the model. The density of the reinforced concrete is about 2.4g/cm^3 while the density of the Epoxy resin is 1.2g/cm^3. As the density of the Epoxy resin is smaller than that of the reinforced concrete, in order to make the mass parameter identical, the iron powder is added into the solvent.Then, the wind tunnel testings on the vortex-induced oscillations of a reinforced concrete chimney are carried out using a model made of this material. The dynamic behavior of the model is compared with the full-scale data, and it is confirmed that the material is available to the wind tunnel testings.Finally, the method for wind resistant design of the reinforced concrete structures with a circular section are proposed.