高层建筑标准模型平均风力的阻塞效应研究

Experimental investigation on blockage effect of mean wind forces of standard high-rise building model

采用一组阻塞比为1.7%、3.1%、4.5%、6.3%、8.6%和10.9%的高层建筑标准模型,分别在均匀低湍流强度风场和均匀高湍流强度风场下进行了多点同步测压试验,研究了阻塞效应对高层建筑平均阻力系数和顺风向平均基底弯矩系数的影响。研究结果表明:在均匀流场下,阻塞效应没有明显改变平均阻力系数沿高度的分布趋势;当阻塞比不大于4.5%时,阻塞效应对高层建筑平均风力的影响可以忽略不计;但当阻塞比大于4.5%时,随着阻塞比的增加,层平均阻力系数和顺风向平均基底弯矩系数逐渐增大;湍流强度的增加,削弱了阻塞效应对平均阻力系数和顺风向平均基底弯矩系数的影响。基于本文试验结果,提出了均匀湍流风场中矩形高层建筑平均阻力系数的阻塞效应修正公式。

Adopting a set of standard high-rise building model, which has blockage ratio of 1.7%, 3. 1%,4.5%, 6. 3%,8.6% and 10. 9% respectively, multipoint synchronous pressure measurement experiment was carried out in smooth flow and in grid turbulent flow respectively.The influence of blockage effect on mean local drag coefficient and along-wind mean base bending moment coefficient of high-rise buildings was studied. Results show that the blockage effect does not change the distribution trend of the mean drag coefficient along the height in uniform turbulent flow, and when the blockage ratio is less than 4. 5%, the influence of the blockage effect on mean wind forces of high-rise building can be neglected. However, when blockage ratio is greater than 4. 5%, with the increase of blockage ratio, the mean local drag coefficient and the along-wind mean base bending moment coefficient gradually increase. The increase of turbulence intensity weakens the influence of blockage effect on mean local drag coefficient and the along-wind mean base bending moment coefficient. Based on experimental results, a blockage effect correction formula for mean local drag coefficient of rectangular high-rise buildings in uniform turbulent flow is proposed.