苏通大桥连续刚构桥主梁混凝土徐变试验研究

Experimental Research on Concrete Creep for Main Girder of Continuous Rigid Frame Bridge of Sutong Bridge

为获得苏通大桥连续刚构桥主梁所用C60高强高性能混凝土的徐变规律,在自然环境条件下开展了不同加载龄期配筋混凝土的徐变试验。对短期徐变试验数据分析得出,5 d和7 d加载龄期的徐变发展较快,当条件许可时,建议推迟实桥节段张拉龄期,以减小早期徐变,从而减小预应力损失。长期试验结果表明,配筋高强高性能混凝土的徐变小于现行桥梁规范公式计算值,徐变发展进程也与现行桥梁规范不同。根据大量的试验结果,采用非线性回归方法对现行桥梁规范徐变计算公式进行了修正,得出实桥所用混凝土的徐变预测公式。利用该公式对分批加载的试验试件进行了计算,计算结果与试验结果符合较好。徐变试验结果和修正的徐变预测公式可为实桥的设计和施工提供参考。

In order to obtain the creep properties of high strength and performance concrete（C60） used in the main girder of continuous rigid frame bridge of Sutong Bridge,creep experiment of reinforced concrete with different loading ages were performed under natural environment.Analysis of short-term creep test shows that creeps with 5 and 7 days loading ages develop rapidly.It is suggested that the tension age of the segmental concrete should be postponed to reduce early creep and prestress loss if condition permitted.Long-term creep test result shows that the test creep values of high strength and performance reinforced concrete are far less than the calculation values in the current bridge code and the test creep development process is also different from that of the code.Based on a number of test results,the creep prediction formula in the current bridge code was revised by using nonlinear regression method.By using the revised creep formula,the creeps of multistage loading test specimens were calculated,which agree well with the test values.Creep test results and the revised creep formula can provide a reference for design and construction of the bridge.