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为获得苏通大桥连续刚构桥所用高强高性能混凝土的收缩徐变规律,在自然环境下开展了为期两年多配筋混凝土(配筋率分别为0、0.38%、0.76%和1.71%)的收缩徐变试验。徐变试件加载应力水平约为15MPa,与实桥最大应力水平相近。加载龄期有四种,分别为7d、14d、21d和28d,分别模拟了实桥节段施工混凝土的加载龄期。在收缩徐变试验基础上拟合出收缩徐变曲线。试验结果表明,实桥所用高强高性能混凝土的收缩徐变小于现行桥梁规范JTGD62-2004取值,配筋混凝土的收缩徐变小于素混凝土的收缩徐变。采用有限元软件ANSYS/CivilFEM分析了配筋对混凝土收缩徐变的影响,分析结果和试验结果一致:当配筋率较低时,配筋对混凝土的收缩徐变影响较小,在工程应用范围内,可以不考虑配筋的影响;当配筋率较高时,配筋可以有效地减小收缩徐变的发展。研究成果可为实桥主梁时变分析提供参考依据。
In order to obtain the shrinkage and creep of high-strength and high-performance concrete used in continuous rigid frame bridge of Sutong Bridge, two-year reinforced concrete (0,0.38%, 0.76% and 1.71%, respectively) Shrinkage and creep test. The loading stress level of creep specimen is about 15MPa, which is close to the maximum stress level of real bridge. There are four loading age, respectively 7d, 14d, 21d and 28d, respectively, to simulate the real bridge segment construction of concrete loading age. On the basis of the shrinkage and creep test, the curve of shrinkage and creep was fitted. The test results show that the shrinkage and creep of high-strength and high-performance concrete used in real bridges is smaller than the value of JTGD62-2004, and the shrinkage and creep of reinforced concrete is smaller than that of plain concrete. The effect of reinforcement on the shrinkage and creep of concrete was analyzed by finite element software ANSYS / CivilFEM. The analysis results agree well with the experimental results. When the rate of reinforcement is low, the reinforcement has little effect on the shrinkage and creep of concrete. , Can not consider the impact of reinforcement; when the reinforcement ratio is high, reinforcement can effectively reduce the development of shrinkage and creep. The research results provide a reference for the time-varying analysis of the main girder of real bridge.