预应力混凝土连续刚构桥施工过程应力监测研究

混凝土实测应变除弹性应变外,还包含混凝土的自由变形、徐变和温度应变等非应力应变,该文介绍了预应力混凝土连续刚构桥中应力间接测量的方法和步骤。在混凝土实测应变与应力的转换中,采用无应力计去除非应力应变,利用预埋在主梁中性轴的应变计进行混凝土徐变系数识别,并采用叠加法对徐变应变进行分离。混凝土内部应力测量的关键在于应力应变转换,而应力应变转换关键在于徐变系数的识别。在观音沙特大桥施工监控期间,先采用中性轴应力来识别徐变系数,再进行徐变应变分离的方法,应力实测值与弹性理论计算值比较接近。

Study of Stress Monitoring in Course of Constructing Pre-stressed Concrete Continuous Rigid Frame Bridge

The concrete measured strain still includes the non-stress strain of the concrete free deformation, creep and temperature strain besides the elastic strain. The article introduces the methods and steps of the stress indirect measurement in the pre-stressed concrete continuous rigid frame bridge. In the conversion of the concrete measured strain and stress, the non-stress meter is used to remove the stress strain, the strain meter embedded in the neutral axis of the main beam is used to distinguish the concrete creep coefficient and the superposition method is used to separate the creep strain. The key of the concrete inner stress measurement is at the conversion of the stress strain, but the key of the stress strain conversion is at the distinguishing of the creep coefficient. In the course of monitoring the construction of Guanyinsha Super-large bridge, the neutral axis stress is firstly used to distinguish the creep coefficient, then the method is used to separate the creep strain. The stress measured value is more closing to the elastic theoretically calculated value.