混凝土徐變預(yù)測(cè)模型修正分析*
曹?chē)?guó)輝1，胡佳星2，張鍇1，何敏1
- 摘 要
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（1 湖南城市學(xué)院土木工程學(xué)院，益陽(yáng) 413000；2 湖南科技大學(xué)土木工程學(xué)院，湘潭 411105）［摘要］對(duì)不同加載齡期的混凝土圓柱體進(jìn)行長(zhǎng)期徐變?cè)囼?yàn)，結(jié)果表明混凝土圓柱體內(nèi)徐變系數(shù)較體外徐變系數(shù)普遍偏小，加載齡期對(duì)混凝土體外徐變系數(shù)影響較大，對(duì)體內(nèi)徐變系數(shù)影響較小。國(guó)內(nèi)外徐變預(yù)測(cè)模型對(duì)短期加載齡期（9d）的徐變系數(shù)預(yù)測(cè)精度較高，對(duì)長(zhǎng)期加載齡期(39d)的徐變系數(shù)預(yù)測(cè)精度較差，特別是對(duì)后期徐變系數(shù)預(yù)測(cè)普遍不足。GZ(1993)模型對(duì)徐變初期預(yù)測(cè)存在不連續(xù)現(xiàn)象，但整體預(yù)測(cè)效果最好。CEB-FIP(1990)模型預(yù)測(cè)效果最差，預(yù)測(cè)徐變系數(shù)的變化規(guī)律與實(shí)測(cè)值偏離較大。采用最小二乘法對(duì)實(shí)測(cè)數(shù)據(jù)進(jìn)行非線性回歸分析，分析表明CEB-FIP(1990)模型對(duì)名義徐變系數(shù)預(yù)測(cè)偏低，這主要是由CEB-FIP(1990)模型中加載齡期影響系數(shù)預(yù)測(cè)偏低造成的。根據(jù)不同加載齡期的徐變系數(shù)實(shí)測(cè)值，對(duì)CEB-FIP(1990)模型進(jìn)行了修正，從而大大提高了徐變預(yù)測(cè)模型的預(yù)測(cè)精度。［關(guān)鍵詞］預(yù)測(cè)模型; 混凝土圓柱; 徐變系數(shù); 理論分析; 試驗(yàn)研究中圖分類號(hào)：TU528.1 文獻(xiàn)標(biāo)識(shí)碼：A 文章編號(hào)：1002-848X(2014)05-0045-05Correction analysis on prediction model of concrete creepCao Guohui1, Hu Jiaxing2, Zhang Kai1, He Min1(1 College of Civil Engineering, Hunan City University, Yiyang 413000, China; 2 College of Civil Engineering, Hunan University of Science and Technology, Xiangtan 411105, China)Abstract: Long-term creep experiment of concrete circular columns with different loading ages was done. The experimental result shows that internal creep coefficient is generally smaller than external creep coefficient, the loading age has great influence on external creep coefficient and little influence on internal creep coefficient. The creep prediction models at home and abroad with short-term loading age(9d) have high predictive accuracy for creep coefficient. The creep prediction models at home and abroad with long-term loading age(39d) have low predictive accuracy for creep coefficient, especially predicted values of creep coefficient are general insufficient in late stage. GZ(1993) model has discontinuous phenomenon for forecasting initial creep coefficient, but predictive effect is best. The predictive effect of CEB-FIP(1990) model is worst, the change rule of predicted values of creep coefficient deviates from measured values. The method of least squares for nonlinear regression analysis of measured data was adopted. The analysis result shows that CEB-FIP(1990) model has low prediction for nominal creep coefficient, and this phenomenon is large due to low prediction for influence coefficient of loading age. According to measured values of creep coefficient with different loading ages, CEB-FIP(1990) model of concrete creep is corrected, which can greatly improve the predictive accuracy of creep prediction model.Keywords: prediction model; concrete circular column; creep coefficient; theoretical analysis; experimental study*湖南省高等學(xué)?？茖W(xué)研究項(xiàng)目（重點(diǎn)項(xiàng)目）(12A027)。作者簡(jiǎn)介：曹?chē)?guó)輝，博士，教授，Email: cgfcivil@163.com。參考文獻(xiàn)［1］桂海清. 混凝土早期收縮與抗裂性能試驗(yàn)研究［D］. 杭州：浙江大學(xué), 2004: 5-9.［2］楊小兵. 混凝土收縮徐變預(yù)測(cè)模型研究［D］. 武漢: 武漢大學(xué), 2004: 15-48.［3］林波. 混凝土收縮徐變及其效應(yīng)的計(jì)算分析和試驗(yàn)研究［D］. 南京: 東南大學(xué), 2004: 15-48.［4］NEVILLE A M, DILGER W H, BROOKS J J. Creep of plain and structure concrete［M］. London: Construction Press, 1983.［5］BAZANT Z P, BAWEJA S. Creep and shrinkage prediction model for analysis and design of concrete structures-model B3［J］. Material and Structures, 1995，28（6): 357-365.［6］ACI Committee 209. Prediction of creep, shrinkage, and temperature effects in concrete structures［M］. Houston: America Concrete Institute, 1992.［7］張克波, 許康, 呂毅, 等. 配筋混凝土柱徐變?cè)囼?yàn)［J］. 長(zhǎng)沙理工大學(xué)學(xué)報(bào)：自然科學(xué)版, 2011, 8(2): 17-20.［8］JTG D62—2004 公路鋼筋混凝土及預(yù)應(yīng)力混凝土橋涵設(shè)計(jì)規(guī)范［S］. 北京: 人民交通出版社, 2004.［9］CEB-FIP mode code 1990［S］. London:Thomas Telford Services Ltd.,1993.［10］劉立新，趙靜超，王俊. 折線先張預(yù)應(yīng)力混凝土簡(jiǎn)支梁徐變撓度試驗(yàn)研究［J］. 建筑結(jié)構(gòu), 2009,39(S2): 117-120.［11］BAZANT Z P, BAWEJA S. Justification and refinements of model B3 for concrete creep and shrinkage［J］. Materials and Structures, 1995,28(7): 488-495.
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