工业厂房屋面脉动风荷载及干扰效应试验研究

Experimental study on fluctuating wind loadings and the interference effects on industrial building roof

随着工业厂房构件的轻型化,厂房屋面受脉动风荷载作用极易发生破坏。通过对某实际厂房刚性模型进行单体与典型干扰工况条件下的风洞测压试验,得到屋面的脉动风压。首先,分析不同工况时的屋盖纵横向端部与中部的测点脉动风压分布规律,对比无干扰工况与干扰工况条件下的屋盖表面脉动风压分布;其次,考察不同干扰距离受扰厂房与无干扰厂房屋盖表面典型测点的功率谱;最后研究屋盖整体升力系数的脉动值、极小值与极大值。结果表明,风向角与干扰距离极大地影响风压脉动值。角部测点与中部测点脉动风压在45°风向角时最大;而纵墙边沿测点的脉动风压系数在90°风向附近最大。干扰距离越小,对脉动值影响越大。处于屋盖表面不同区域的测点功率谱表现出不同形态,干扰对不同位置测点的作用效应不同,对不同频段的能量影响也不同。干扰工况对升力系数最大脉动值与最不利极小值表现为遮挡效应,而对最不利极大值起放大效应。给出不同干扰工况时的屋盖升力系数的脉动值与极值干扰因子,以供工程实际设计参考。

With the trend of application of light components,roofs of industrial buildings are vulnerable to fluctuating wind loadings.Wind tunnel tests for an isolated practical industrial building and two industrial buildings with different separation distances were carried out and the data of fluctuating pressures were obtained.The distribution rules of fluctuating pressure were explored for different conditions and the comparison analyses on the interference conditions and isolated condition were made for the fluctuating pressures.Meanwhile,the PSD of fluctuating pressures of typical taps on roof were analyzed.Special attention was paid to the fluctuating and maximum and minimum entire roof lift coefficients.The results show that wind direction and the interference distance have greater influences on fluctuating pressures.The maximum fluctuating pressures of corner and center zones occur at 45°wind direction,though edge zones on long walls at 90°wind direction.The less the interference distance is,the greater the effects of interference to fluctuating pressures are.The PSD for the taps on various regions of the roof have different patterns.The effects of interference vary for different taps and different bands of the wind pressure spectra.Moreover,shielding effects are observed for maximum RMS lift coefficients and the most unfavorable minimum lift coefficients,but amplification effects are observed for the most unfavorable maximum lift coefficients.The interference factors(IF) are calculated for fluctuating and extreme lift coefficients providing the references for engineering designs.