世博軸索膜結構抗風設計中等效風荷載研究
汪大綏，盧旦，李承銘，田煒
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(上?，F(xiàn)代建筑設計(集團)有限公司，上海 200041)［摘要］索膜結構頻率密集、非線性現(xiàn)象嚴重，其等效風荷載的取值成為結構抗風設計的關鍵。采用計算流體動力學中的非穩(wěn)態(tài)計算方法，對世博軸索膜結構表面風荷載進行了數(shù)值風洞計算；繼而將計算得到的風荷載時程直接加載到有限元模型上，進行結構的動力時程分析。數(shù)值風洞計算結果表明：非穩(wěn)態(tài)計算不但可以直接獲得結構表面的風荷載時程，而且可以準確捕捉到跨臨界狀態(tài)下的漩渦脫落。結構動力時程分析結果表明：索膜結構的風振響應中以背景響應為主，共振響應可忽略不計。采用最大風荷載法得到的計算結果與時程計算結果吻合較好。［關鍵詞］索膜結構；數(shù)值風洞；抗風設計；等效風荷載Study on equivalent wind load for cable-membrane structure in wind-resistant design of EXPO AxisWang Dasui, Lu Dan, Li Chengming, Tian Wei(Shanghai Xian Dai Architectural Design (Group) Co., Ltd., Shanghai 200041, China)Abstract:Some of the disadvantages, such as closely spaced frequencies and highly nonlinear nature, make cable-membrane structure sensitive to wind load. Using the unsteady calculation, the surface wind pressure on cable-membrane structure of EXPO Axis was simulated by means of the numerical wind tunnel method. Directly using pressure data of the numerical wind tunnel test, the free vibration of a practical cable-membrane structure was analyzed by using the finite element program, and the wind-induced vibration response of the structure was theoretically analyzed. The result shows that use of unsteady simulation not only can obtain wind load time history on structure directly, but also can catch vortex shedding correctly. The nonlinear dynamic time-history analysis shows that, the background response takes the significant part of the total dynamic response, and the resonant response can be neglected. The results by using the instantaneous effect maximum wind method agree well with the time history analysis ones.Keywords:cable-membrane structure; numerical wind tunnel; wind-resistant design; equivalent wind load*上海市科學技術委員會科研計劃項目世博科技項目(08dz0580305)；國家科技支撐計劃項目世博科技項目(2009BAK43B06)。作者簡介：汪大綏，總工，中國工程勘察設計大師。參考文獻［1］黃本才，汪從軍.結構抗風分析原理及應用［M］.第二版.上海：同濟大學出版社，2008.［2］GB50009—2001建筑結構荷載規(guī)范［S］.北京：中國建筑工業(yè)出版社，2001.［3］盧旦，李承銘，王國儉.上海金茂大廈風振響應的CFD非穩(wěn)態(tài)數(shù)值模擬分析［J］.土木工程學報，2008，41(8)：31-35.
