中文摘要：

为了研究外部平台宽度对大跨屋盖风荷载的影响，在B类地貌中对无平台和5个典型平台宽度下的刚性模型进行风洞测压试验，得到了各工况下的屋盖表面平均风压系数和脉动风压系数．研究表明：外部平台增大了大跨结构屋盖的平均风荷载．随着平台宽度的增大，屋盖的平均风荷载先增大后减小．平台宽度12m时最不利，其最大增幅达到33％．平台宽度20m时增幅达到20％；外部平台增大了大跨结构屋盖的脉动风荷载，平台宽度12m时最不利，其增幅达到11％．平台宽度20m时，增幅为8％，其余平台宽度下的增幅基本在5％以内．屋盖背风面边缘的脉动风荷载随着平台宽度的增加而减小，平台宽度20m时可达19%。

英文摘要：

In order to study the influence of external platform width on wind loads of large-span build- ings, wind tunnel tests of six rigid models with various platform widths were carried out. In particular, the characteristics of mean wind pressure coefficient and fluctuating wind pressure coefficient were studied. The test results show that the enlargement of platform widths increases the mean wind loads. The mean wind loads change from small to large and to small again with the increase of platform width. The most unfavorable situation occurs when the platform width is 12 meters, and its growth rate reaches 33%, while its growth rate is 20- when the platform width is 20 meters. Meanwhile, the increase of platform widths increases the fluctuating wind loads. The most unfavorable situation takes place when the platform width is 12 meters, and its growth rate reaches 11%, while its growth rate is 8% when the platform width is 20 meters, and the rate is lower than 5% in other cases. The fluctuating wind loads on the leeward side de- crease when the width of platform increases. The maximum decrease reaches 7% when the platform width is 20 meters.