通过对轴心受压素混凝土柱、表面涂胶混凝土柱和CFRP约束混凝土柱受力变形性能的长期观测,研究了不同表面处理混凝土轴心受压短柱在长期荷载作用下的徐变发展规律。结果表明:其他条件相同时,CFRP约束混凝土柱的徐变与涂胶混凝土柱的相近,均较素混凝土柱小约20%。CFRP约束混凝土柱的徐变减小,主要是粘贴CFRP布时的胶层所致而非核心混凝土的约束效应。采用AC1209R(92)和CEB-FIP(MC90)两种徐变模型进行理论计算,并提出了基于ACI1209R(92)模型的CFRP约束混凝土徐变修正计算式,试验数据与理论预测模型吻合良好。
Based on the long-term observation of stress deformation behaviors of concrete columns with three different methods for surface treatment, i.e. coat free, epoxy coated and CFRP confined, the law of creep development in concrete columns under longterm loading in axial direction in above three cases is studied. The result shows that the creep coefficients of the CFRP-confined concrete column and the epoxy-coated column are close to each other, and about 20% less than that of the plain concrete column under the same condition, and that the creep reduction in the CFRP-confinod concrete column is not caused by the restraint effect of core concrete but mainly caused by the existence of epoxy coating. Theoretical calculation is performed by use of the ACI209R (92) and CEB-FLP(MC90) models, and a formula for creep rectification in CFRP-confined concrete column is proposed based on the ACI209R(92) model. The predicted results of the model are in good agreement with the experimental data.