- 摘 要
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饒芝英 童根樹
（浙江大學土木系 杭州 310027）[提要] 在材料和截面層次上剛度達到零定義了傳統(tǒng)的強度極限狀態(tài)，而在構(gòu)件和結(jié)構(gòu)（子結(jié)構(gòu)）層次上的剛度等于零即達到了穩(wěn)定極限狀態(tài)。這種層次的區(qū)分清晰地表達了強度問題和穩(wěn)定問題的區(qū)別和內(nèi)在聯(lián)系，解釋了具有正剛度的構(gòu)件或結(jié)構(gòu)在荷載作用下產(chǎn)生失穩(wěn)的原因，引入了荷載的負剛度概念，并提出了荷載負剛度的計算公式，有助于工程師理解穩(wěn)定的基本概念和掌握結(jié)構(gòu)穩(wěn)定的計算方法。此外，還提出了為使廠房柱平面外計算長度達到側(cè)向支承點之間的距離而必須的支撐剛度的最低要求。
[關(guān)鍵詞] 鋼結(jié)構(gòu) 構(gòu)件 穩(wěn)定 剛度 強度Limit states are reached when the stiffnesses in material cross-section member, subassemblage and overall structure levels become zero. This classification shows clearly the difference and their relationship between the strength and the stability problems. Authors also provide an explanation of why compressed members become unstable under vertical loads. The concept of negative stiffness of the vertical load is introduced, and an expression for determining this negative stiffness is also provided. The minimum stiffness of longitudinal braces in industrial building is also suggested in order to make the out-of-plane effective length of the column reach the distance between the braced points.
Keywords: steel structure; section; subassemblage; stability; stiffness; strength
