框架高階屈曲波形的應用價值分析*
金波1，童根樹2，鄭君華1
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（1 杭州科技職業(yè)技術(shù)學院， 杭州 311400； 2 浙江大學建筑工程學院， 杭州 310058）
［摘要］對頂層抽柱的四層三跨鋼框架進行屈曲分析,采用傳統(tǒng)計算長度系數(shù)法計算層抗側(cè)剛度，并與SAP2000軟件計算的層抗側(cè)剛度比較發(fā)現(xiàn),施加水平荷載求得的各層剪力之比與采用臨界荷載方法計算的層抗側(cè)剛度之比相等時，兩者結(jié)果接近。對鋼框架進行整體屈曲分析，指出第1屈曲模態(tài)對應的是薄弱層的屈曲，第2及以上屈曲模態(tài)因不能正確反映框架梁對框架柱的約束，不能直接加以應用。頂層抽柱導致屋面梁軸力加大，自身臨界荷載降低，使得屋面梁對頂層柱的轉(zhuǎn)動約束作用減小或消失，需要在頂層柱計算長度系數(shù)計算中予以考慮。［關(guān)鍵詞］變截面梁; 計算長度系數(shù)法; 矩陣位移法; 屈曲因子; 抗側(cè)剛度; 臨界荷載中圖分類號：TU391 文獻標識碼：A 文章編號：1002-848X(2015)21-0047-05
Application value analysis of high order buckling wave of frameJin Bo1, Tong Genshu2, Zheng Junhua1（1 Hangzhou Polytechnic College, Hangzhou 311400, China; 2 School of Architecture & Engineering, Zhejiang University, Hangzhou 310058, China）Abstract: The buckling analysis of a four-layer and three-span steel frame without some columns in top layer was carried out by using the traditional calculation length coefficient method to calculate the lateral resistance stiffness of the layer. The comparison of the lateral resistance stiffness by traditional method and by the SAP2000 software was carried out. Results show that two results are close when the ratio of the shear force of each layer by the horizontal load is equal to that the ratio of the lateral resistance stiffness of the layer by critical load method. The overall buckling analysis of the steel frame was carried out, and the first buckling mode is pointed out to be the buckling of weak layer, and the second and higher buckling modes can not be used because they can not reflect the constraint of frame beam to frame column correctly. Lacking of some columns in top layer leads to increase of axial force in roof beam, decrease of critical load, and the decrease or disappearance of the rotation constraint action of roof beam to frame column, which needs to be considered in calculation of calculation length coefficient of column in top layer.Keywords: beam with variable cross-section; calculation length coefficient method; matrix displacement method; buckling factor; lateral resistance stiffness; critical load
*杭州市科技局重點項目（20100333T25），浙江省教育廳科研項目（Y201122425, Y201223824）。作者簡介：金波，碩士，副教授，高級工程師，Email：jb@mail.hzaspt.edu.cn。
