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(同濟(jì)大學(xué)建筑工程系 上海 200092)
【提要】 上海南站是國內(nèi)外第一座大型圓形火車站建筑，該建筑屋蓋為預(yù)應(yīng)力索梁結(jié)構(gòu)體系，大跨度鋼梁特殊的平面呈Y形，截面為橄欖形薄壁閉口截面，使結(jié)構(gòu)設(shè)計(jì)有較大難度。介紹了結(jié)構(gòu)局部模型邊界條件的確定方法，運(yùn)用大型有限元分析軟件MSC.MARC詳細(xì)分析了該梁的極限承載力，為該結(jié)構(gòu)設(shè)計(jì)提供了可靠的計(jì)算依據(jù)，為此類結(jié)構(gòu)的分析提供有價(jià)值的參考資料。計(jì)算結(jié)果表明，只有綜合考慮結(jié)構(gòu)的幾何和材料非線性才能準(zhǔn)確評估出結(jié)構(gòu)的極限承載力。
【關(guān)鍵詞】 橄欖形薄壁閉口截面 彈性邊界條件 幾何非線性 材料非線性 極限承載力 Y形梁 鋼梁
Ultimate Bearing Capacity Analysis of Yshape Girder of Roof Steel Structure of Shanghai South Railway Station/Su Ci, Luo Yongfeng, Shen Zuyan, Guo Xiaonong (Department of Building Eng., Tongji Univ., Shanghai 200092, China)
Abstract:Shanghai south railway station is the first large round building of which roof is a system of prestressed cables and beams. The steel girders of the roof structure are closed ellipse sections, which bring out difficulties for design. The methods to specify boundary conditions applying to local model are discussed. The ultimate bearing  capacity of the girder is analyzed by using MSC.MARC，which provides reliable basis for the structure design.The analysis procedure  can be reference for similar structure design. The results indicate that the ultimate bearing capacity of structure can be evaluated exactly when considering both geometric nonlinear and material nonlinear.
Keywords:ellipse closesection shape; elastic boundary condition; geometric nonlinear; material nonlinear; ultimate bearing capacity; Ysteel girder;