彎扭失穩(wěn)換算長細比的一致公式
倪聞昊，王俊
- 摘 要
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（浙江大學(xué)建筑設(shè)計研究院， 杭州 310028）［摘要］彈性屈曲荷載并不能直接看作是承載力，實際壓桿存在初始彎曲，在彈塑性階段失穩(wěn),需要改用極限承載力理論來確定壓桿的穩(wěn)定承載力。通過歐拉公式提供中間參數(shù)得到換算長細比的計算穩(wěn)定系數(shù)，從而得到構(gòu)件的承載能力。因此《鋼結(jié)構(gòu)設(shè)計規(guī)范》采用換算長細比來查穩(wěn)定系數(shù)φ，計算構(gòu)件的極限承載力。然而規(guī)范給出的換算長細比公式缺乏一致性，是一個分段函數(shù)。由壓桿彎曲失穩(wěn)和扭轉(zhuǎn)失穩(wěn)互相作用得到啟發(fā)，提出雙角鋼組合T形截面和等邊單角鋼繞對稱軸彎扭失穩(wěn)換算長細比的一致性公式。［關(guān)鍵詞］壓桿； 角鋼； 彎扭屈曲； 穩(wěn)定； 換算長細比中圖分類號：TU323 文獻標識碼：A 文章編號：1002-848X(2013)15-0127-04Consistent formula of equivalent slenderness ratio for flexural-torsional bucklingNi Wenhao, Wang Jun(Archtectural Design and Research Institute of Zhejiang University, Hangzhou 310028, China)Abstract: The elastic buckling load can not be directly seen as bearing capacity. Actually the component exist initial bending, the limit supporting capacity theory is needed to determine the stable bearing capacity of component in the elastic-plastic phase. The Euler’s formula provides the slenderness ratio calculates. Through equivalent slenderness ratio to calculate the stability coefficient, it can obtain the bearing capacity of the component. So Code for design of steel structures adopts equivalent slenderness ratio to search stability coefficient. However, the equivalent slenderness ratio given by GB 50017—2003 is lack of consistency, and is a sub-part function. Inspired by the interacting of flexural and torsional buckling, it presents consistent equivalent slenderness ratio formula of struts of monosymmetric section T shape section built with the double angle steel and an equal sides angle steel buckling around axis of symmetry.Keywords: strut; angle steel; flexural-torsional buckling; stability; equivalent slenderness ratio作者簡介：倪聞昊，碩士，助理工程師，Email:niwenhaohotmail@163.com。參考文獻［1］KENNEDY J B,MURTY M K S. Buckling of steel angle and T-struts［J］. Journal of the Structural Division, ASCE, 1972,98(STII):2507-2522.［2］陳紹蕃. 角鋼、剖分T型鋼壓桿的彎扭屈曲（2）［J］.鋼結(jié)構(gòu)，2001,51(16):46-48.［3］方山峰. 冷彎薄壁型鋼梁的整體穩(wěn)定［J］. 工業(yè)建筑, 1986,4(1)：41-45.［4］方山峰. 壓彎桿件彎扭屈曲的換算長細比［J］.鋼結(jié)構(gòu)，1987, 3(1):38-42.［5］金尼克 A H.拱的穩(wěn)定性［M］.呂子華,譯.北京:中國建筑工業(yè)出版社,1958.［6］TIMOSHENKO S P, GERE J M. Theory of elastic stability［M］. 2nd ed. McGraw-Hill, New York, 1961.［7］呂烈武，沈世釗，沈祖炎，等. 鋼結(jié)構(gòu)構(gòu)件穩(wěn)定理論 ［M］.北京：中國建筑工業(yè)出版社，1983.［8］CULVER C G. Exact solution of the biaxial bending equations［J］. Journal of the Structural Division, ASCE, 1996, 92(1):63-83.［9］GB 50017—2003 鋼結(jié)構(gòu)設(shè)計規(guī)范［S］. 北京：中國計劃出版社,2003.［10］陳紹蕃.鋼構(gòu)件容許長細比芻議［J］. 建筑結(jié)構(gòu)， 2009,39(2):113-115.［11］CHEN S F, SU M Z. Ou-to-f plane buckling and bracing requirement in double-angle trusses ［J］. Steel and Composite Structures, 2003, 3(4):261-275.［12］周緒紅,萬紅霞. 軸心壓桿截面設(shè)計時選定長細比λ的簡便方法［J］. 鋼結(jié)構(gòu)，1996，34（11）:37-41.
