下击暴流作用下大跨平屋面的极值风压分析  

Extreme wind pressure analysis for large-span flat roof under downburst

作　　者：汪之松[1,2] 向明 江水灵 唐阳红 WANG Zhisong;XIANG Ming;JIANG Shuiling;TANG Yanghong(School of Civil Engineering,Chongqing University,Chongqing 400045,China;MOE Key Lab New Technology for Construction of Cities in Mountain Area,Chongqing University,Chongqing 400045,China)

机构地区：[1]重庆大学土木工程学院,重庆400045 [2]重庆大学山地城镇建设与新技术教育部重点实验室,重庆400045

出　　处：《振动与冲击》2022年第11期83-89,共7页Journal of Vibration and Shock

摘　　要：在下击暴流风场中,大跨平屋面建筑顶部的来流分离区及尾流区域处风压具有极强的非高斯特性。基于稳态冲击射流作用下的大跨平屋面建筑刚性测压试验结果,使用高阶统计量法研究了典型径向距离处屋面风压高斯与非高斯分区特性,利用TPP法计算测点峰值因子,发现平屋面表面测点极值风压系数与建筑物离下击暴流喷口间距有密切关系,研究结果表明:在下击暴流作用下,大跨平屋面部分区域出现明显的风压非高斯特性,尤其是迎风和背风边缘区域;屋面中心区域和屋面侧边缘区域峰值因子较小,屋面峰值因子取值范围在3.99~9.29,测点峰值因子均明显大于《建筑结构荷载规范》中的取值;在不同径向距离处,极值风压系数均为负值,来流分离区域及尾流区域风压系数绝对值较大;极小值风压系数绝对值随径向距离的增加先增大再减小,在径向距离为1.25 D_(jet)时极小值风压系数绝对值出现最大值。In downburst wind field,wind pressure in incoming flow separation area and wake area on top of large-span flat roof building has strong non-Gaussian characteristics.Based on rigid pressure measurement test results of large-span flat roof buildings under action of steady-state impinging jet,Gaussian and non-Gaussian zoning characteristics of roof wind pressure at places with typical radial distance were studied by using the high-order statistics method,peak factors at measured points were calculated with TPP method.It was shown that extreme wind pressure coefficients of measured points on surface of flat roof are closely related to the distance between building and downburst nozzle.The results showed that under action of downburst,obvious non-Gaussian characteristics of wind pressure appear in part areas of large-span flat roof,especially,in edge areas of windward surface and leeward one;peak factors in center area and edge area of roof crosswind surface are smaller,roof peak factors are in the value range of 3.99-9.29,and peak factors of measured points are obviously larger than those specified in the load code of building structures;at places with different radial distances,extreme wind pressure coefficients are all negative,and absolute values of wind pressure coefficients in incoming flow separation area and wake area are larger;the absolute value of minimum wind pressure coefficient firstly increases and then decreases with increase in radial distance;when the radial distance is 1.25 D_(jet),the absolute value of minimum wind pressure coefficient reaches the maximum.

关 键 词：冲击射流 大跨平屋面建筑 非高斯特性 峰值因子 极值风压系数 

分 类 号：TU312.1[建筑科学—结构工程]