短期低应力徐变作用后钢筋混凝土梁静力试验研究
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摘要
混凝土徐变在加载初期发展很快,此时期结构往往处于施工期,承受较低的应力,但目前关于短期低应力徐变作用对钢筋混凝土梁静力特性影响的研究较少.文中设计制作3根相同尺寸和配筋的钢筋混凝土梁,经过不同时间短期低应力堆载后,对钢筋混凝土梁进行静载试验研究.试验结果表明,经过短期低应力徐变作用后的梁,在较低水平的静载作用时,随堆载徐变时间的增加,其跨中挠度显著增大,且挠度随荷载的增长速率亦增大;而梁侧裂缝的最大宽度和平均宽度随堆载徐变时间的增加而减小,且减小幅度较大.
Concrete creep develops rapidly in the early stages of loading, and the structure of this period is usually in the construction period and is subject to lower stress. However, there are few studies on the effects of short-term and low stress creep on the static characteristics of reinforced concrete beams. In this paper, static load tests have been carried out on three reinforced concrete beams after different short-term and low stress creep. The results show that with the increase of creep time, the mid-span deflection of the beam increases significantly at a lower level of static loading; the growth rate of deflection increases with the load increase; the maximum width and average width of cracks on the beam side decrease greatly when the creep time increases.
Concrete creep develops rapidly in the early stages of loading, and the structure of this period is usually in the construction period and is subject to lower stress. However, there are few studies on the effects of short-term and low stress creep on the static characteristics of reinforced concrete beams. In this paper, static load tests have been carried out on three reinforced concrete beams after different short-term and low stress creep. The results show that with the increase of creep time, the mid-span deflection of the beam increases significantly at a lower level of static loading; the growth rate of deflection increases with the load increase; the maximum width and average width of cracks on the beam side decrease greatly when the creep time increases.
引文
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[13]Davis R E,Davis H E.Flow of concrete subjected to cyclic and sustained loading[J].ACI Journal,1970,67(10):816-827.
[14]罗许国,钟新谷,戴公连.高性能混凝土梁长期变形性能试验研究[J].铁道科学与工程学报,2005,2(4):45-49.
[15]林波.混凝土收缩徐变及其效应的计算分析和试验研究[D].南京:东南大学,2006.
[16]邓宗才,徐海宾,李辉,等.高性能混凝土徐变规律的试验研究[J].北京工业大学学报,2013,39(6):897-901.
[2]刘国军,杨永清,郭凡,等.混凝土单轴受压时的徐变损伤研究[J].铁道建筑,2012(12):163-165.
[3]赵启林,陈立,翟可为,等.复杂状态下桥用高强混凝土收缩徐变性能试验[J].解放军理工大学学报(自然科学版),2011,12(5):459-465.
[4]陈明宪,彭建新,颜东煌,等.钢管混凝土拱桥收缩徐变问题综述[J].长沙交通学,2004,20(2):19-24.
[5]Gianluca R,Graziano L,Riccardo Z.State of the art on the timedependent behavior of composite steel-concrete structures[J].Journal of Constructional Steel Rescarch,2013,80:252-263.
[6]蒲心诚.超高强高性能混凝土[M].重庆:重庆大学出版社,2004.
[7]Bazant Z P,Kim S S.Nonlinear Creep of Concrete-adaptation and flow[J].ASCE J Eng Mech Div,1979,105(3):429-446.
[8]刘国军.基于变形的混凝土梁桥损伤机理研究[D].成都:西南交通大学,2012.
[9]高虎,刘光廷,陆风崎.混凝土双轴压缩徐变试验初步研究[J].清华大学学报(自然科学版),2001,41(11):110-113.
[10]郑丹,李鑫鑫.混凝土在持续荷载下的强度[J].重庆交通大学学报,2010,29(2):190-193.
[11]童智洋.混凝土收缩徐变对连续曲线箱梁桥的受力影响[J].铁道建筑,2010(6):14-15.
[12]吴韶斌.长期持续荷载下的混凝土徐变破坏研究[D].重庆:重庆交通大学,2013.
[13]Davis R E,Davis H E.Flow of concrete subjected to cyclic and sustained loading[J].ACI Journal,1970,67(10):816-827.
[14]罗许国,钟新谷,戴公连.高性能混凝土梁长期变形性能试验研究[J].铁道科学与工程学报,2005,2(4):45-49.
[15]林波.混凝土收缩徐变及其效应的计算分析和试验研究[D].南京:东南大学,2006.
[16]邓宗才,徐海宾,李辉,等.高性能混凝土徐变规律的试验研究[J].北京工业大学学报,2013,39(6):897-901.