大跨度多肢屋盖风荷载特性试验与模拟研究

我国现有建筑荷载规范对复杂大跨度结构的风荷载取值缺乏明确规定。因此,以成都某超大跨度多肢屋盖形式的航站楼为例,采用刚性测压模型风洞试验和数值模拟相结合的方法,研究了该超大跨度屋盖在24个风向角下的风荷载分布规律,并对比验证了现有计算流体动力学方法对复杂大跨屋盖风荷载模拟的有效性和准确性。结果表明:大跨度多肢屋盖上表面基本为负压,各分肢由于外挑屋檐弧度大、转角多、顺风深度窄,屋盖负压值较其他区域更大,是此类屋盖设计时应重点加强的部位;270°为最不利风向角,由于迎风宽度较大,C指廊迎风向屋檐转角处平均风压系数达到-1.4。0°风向角下由于周边建筑高度较低,进深较短,尾流对试验段航站楼影响基本可以忽略;负风压系数负值沿屋檐外轮廓曲线变化呈两端大中间小的趋势。数值风洞对平均风压系数的模拟结果与试验结果吻合较好。

Experimental Study and Numerical Simulation of Wind Load Characteristics on a Long-span Multiple Roof Structure

The new terminal of Chengdu Tianfu Airport is a complex super large-span roof but the corresponding value of wind loads have not been specified in the current Chinese wind code. Therefore, this -study- reported herein investigates the wind load characteristics of this complex large-span roof under 24 wind directions through combined wind tunnel tests and numerical simulations. Also, the accuracy and effectiveness of Computational Fluid Dynamics (CFD) on this issue is validated and verified as compared to the wind tunnel measurements. The results indicate that the wind loads on this roof is generally negative, and particularly large magnitudes of negative pressures are observed on limbs of this roof due to and corners. It is, therefore, suggested that more attention should be paid to the limb regions during wind-resistant design. The mean wind pressure coefficient achieves -1.4 under the unfavorable wind direction of 270°. The influence of wake on the experimental terminal can be ignored under 0° direction because of low-rise buildings surrounded. The negative wind pressure coefficient is large in the middle but small at both ends along the roof. In addition, the mean wind pressure coefficients simulated using the numerical wind tunnel agree well with experimental measurements.