基于构件尺度的预应力混凝土徐变模型研究

Study on Creep Model of Pre-stressed Concrete Based on Component Scale

为评估核电厂安全壳结构的长期预应力损失,以预应力混凝土梁为研究对象,采用试验研究与理论分析相结合的方法,建立预应力混凝土徐变预测模型。在已有的预应力混凝土梁徐变试验基础上,采用相同的混凝土材料进行相同环境下的收缩试验,以测定预应力混凝土梁的实际收缩变形。考虑到混凝土收缩、徐变、预应力筋松弛的耦合作用,引入龄期调整有效模量法,建立由试验数据推导混凝土徐变系数的计算方法,最终建立预应力混凝土徐变模型并预测其长期徐变变形,为核电厂安全壳结构长期预应力损失评估提供了理论支撑。

To assess long-term pre-stress loss of nuclear power plant containment,the creep prediction model of pre-stressed concrete is established by combining experimental investigation with theoretical analysis by taking pre-stressed concrete beam as the research object.Based on the existing creep test of pre-stressed concrete beams,the shrinkage test of pre-stressed concrete beams under the same environment is carried out with the same concrete materials to measure the actual shrinkage deformation of pre-stressed concrete beams.Considering the coupling effect of concrete shrinkage,creep and pre-stressed tendon relaxation,the age adjusted effective modulus method is introduced to establish the calculation method of concrete creep coefficient derived from the test data.Finally,the creep model of pre-stressed concrete is established and its long-term creep deformation is predicted,which provides a theoretical support for the long-term pre-stress loss assessment of nuclear power plant containment structure.