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（重慶三峽學(xué)院土木工程學(xué)院， 重慶 404000）
［摘要］為了研究疲勞荷載作用下鋼筋混凝土梁承載力退化規(guī)律，在研究其疲勞剛度退化基礎(chǔ)上建立了承載力退化模型。首先基于截面有效慣性矩理論并考慮剛度折減得到了靜載作用下鋼筋混凝土梁的剛度計(jì)算表達(dá)式； 然后，將得到的靜載短期剛度作為疲勞荷載作用下梁的初始剛度，通過選擇退化函數(shù)、采用數(shù)據(jù)擬合確定函數(shù)參數(shù)后建立了疲勞荷載作用下的剛度退化計(jì)算公式； 最后，以疲勞損傷作為紐帶，通過挖掘剛度損傷和承載力損傷之間的內(nèi)在關(guān)系，建立了疲勞荷載作用下鋼筋混凝土梁基于剛度退化的承載力退化模型。研究結(jié)果表明:承載力在疲勞初期、構(gòu)件接近破壞階段下降較快，而中間較長時(shí)間基本呈線性退化，并與剛度的衰減較為一致，退化曲線都呈現(xiàn)S形形態(tài)； 通過建立的承載力退化模型，可以用最少量剩余承載力的破壞性試驗(yàn)，實(shí)現(xiàn)疲勞后鋼筋混凝土梁承載力的準(zhǔn)確、快速、有效預(yù)測。
［關(guān)鍵詞］橋梁工程； 鋼筋混凝土梁； 疲勞剛度； 剛度退化函數(shù)； 承載力退化模型
中圖分類號：TU375, U441-4文獻(xiàn)標(biāo)識碼：A文章編號：1002-848X(2020)22-0099-06
Research on bearing capacity degradation model of reinforced concrete beams based on fatigue stiffness degradation
LIU Fangping, YI Wentao
(School of Civil Engineering, Chongqing Three Gorges University, Chongqing 404000, China)
Abstract:In order to study the degradation law of bearing capacity of reinforced concrete beams under fatigue load, bearing capacity degradation model was established based on the study of fatigue stiffness degradation. Firstly, based on the effective moment of inertia theory of cross-section and considering stiffness reduction, the stiffness calculation expression of reinforced concrete beams under static load was obtained. Then, the short-term stiffness under static load was taken as the initial stiffness of beams under fatigue load, and the stiffness degradation calculation formula under fatigue load was established by choosing the degradation function，in the process, data fitting method was used to determine function parameters. Finally, fatigue damage was taken as the link, a bearing capacity degradation model of reinforced concrete beams under fatigue load based on stiffness degradation was established by excavating the internal relationship between stiffness damage and bearing capacity damage. The results show that the bearing capacity decreases rapidly in the initial fatigue stage and near failure stage, and the linear degradation occurs in the middle for a long time, which is consistent with the attenuation of stiffness, and both of them present the S-type degradation curves. Through the bearing capacity degradation model established, the bearing capacity of reinforced concrete beams can be accurately, rapidly and effectively predicted by the minimum destructive bearing capacity experiment of residual bearing capacity.
Keywords:bridge engineering； reinforced concrete beam； fatigue stiffness； stiffness degeneration function； bearing capacity degradation model
*重慶市自然科學(xué)基金項(xiàng)目（cstc2018jcyj，AX0360），重慶市教委科學(xué)技術(shù)研究項(xiàng)（KJQN201901207，KJQN202001204），重慶市三峽水庫岸坡與工程結(jié)構(gòu)災(zāi)變防控工程技術(shù)開放基金項(xiàng)目（SXAPGC18ZDI01）。
作者簡介：劉芳平，博士，副教授，碩士生導(dǎo)師，Email：115090140@qq.com。
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