多国规范平屋盖围护结构外表面设计风压对比研究

对比分析了中国GB 50009-2012、德国DIN 1055-4、美国ASCE/SEI 7-10、日本AIJ-2004、欧洲BS EN 1991-1-4:2005、加拿大NBC-2005、澳大利亚/新西兰AS/NZS 1170.2:2011、英国BS 6399-2:1997等规范中关于平屋盖围护结构外表面设计风压的有关规定。为便于比较，将各国规范风荷载标准值统一换算为外表面设计风压系数与基本风压乘积的形式。并且将外表面设计风压统一换算为与时距10min、重现期50a的基本风速相对应的值。针对外表面设计风压相关因素，对风向、风压分区、面积折减、建筑尺寸等进行了对比研究。最后，结合平屋盖风洞试验，探讨了外表面设计风压的具体取值建议。研究表明：平屋盖围护结构外表面设计风压的确定，建议考虑360°全风向；对屋盖边缘应进行风压分区，角部也应进行单独的风压分区；屋盖表面不同位置建议采用不同的面积折减公式；针对不同高度或宽高比建筑给定不同的外表面设计风压建议取值。

Comparative study on external pressure coefficient of enclosure for flat roof by eight different codes and standards

A detailed comparison on external pressure coefficient of the enclosure structure on flat roof has been made among codes and standards of various countries and regions including China (GB 50009—2012), Germany (DIN 1055-4), USA (ASCE/SEI 7-10), Japan (AIJ-2004), Europe (BS EN 1991-1-4:2005), Canada (NBC-2005), Australia/New Zealand (AS/NZS 1170.2:2011) and Britain (BS 6399-2:1997). In order to make a good comparison, wind load values of different codes and standards have been converted into the product form of the external pressure coefficient and the basic wind pressure. At the same time, external pressure coefficient has been converted into a value which is corresponding to a basic wind speed of 10 min duration and 50 years return period. The comparison and summary of factors which are related to external pressure coefficient also have been made. These factors are wind direction, building height, building size ratio, area reduction and external pressure coefficient partition. In the end, the applications of different standards have been discussed by flat roof wind tunnel tests, and some suggestions for the value selection of the enclosure structure external pressure coefficient of flat roof have been put forward. The most unfavorable wind pressure should be determined considering all 360° for the design of the enclosure structure on flat roof. The edge and corner areas should be partitioned for the wind pressure calculation. Various area reduction formulas should be used for various locations of a roof. Various external wind pressures should be used to buildings with various height or width-to-height ratios.