【作者】 郭瑞峰；

【导师】 王震宇；

【作者基本信息】 哈尔滨工业大学 ， 结构工程， 2010， 硕士

【摘要】 虽然国内外对碳纤维增强复合材料(Carbon Fiber Reinforced Polymer, CFRP)约束混凝土本构关系进行了较多研究,但依然存在以下问题:(1)大量研究针对的是碳纤维约束素混凝土试件,没有考虑钢筋的存在对本构关系的影响;(2)多采用分段的方程形式来描述CFRP约束混凝土圆柱的单调应力—应变关系,参数较多且确定复杂,有的模型在两段连接处不可导;(3)目前还没有可描述CFRP约束钢筋混凝土方柱在中等约束情况下的单调本构模型,急需开展CFRP中等约束钢筋混凝土方柱单调及反复受压滞回本构的研究。针对上述问题,本文通过CFRP约束钢筋混凝土圆柱、方柱的单调及反复受压试验,系统研究了考虑钢筋影响的单调与滞回本构模型,在材料层面上为碳纤维抗震加固混凝土结构的非线性分析与设计提供依据,对完善和发展我国混凝土结构抗震加固设计方法具有重要的理论意义和实用价值。本文主要研究工作如下:1.通过20个直径204 mm,高612 mm的碳纤维约束钢筋混凝土圆柱和18个边长204 mm,高612 mm的碳纤维约束钢筋混凝土方柱的单调及反复受压试验,考察了钢筋对CFRP约束混凝土单调及反复受压性能的影响;发现钢筋对CFRP约束混凝土圆柱单调受压应力—应变关系的影响较小,但对方柱的影响很大,且钢筋的存在对圆柱和方柱反复受压滞回本构关系的影响都较大,说明CFRP约束混凝土本构模型中应考虑钢筋的影响;2.建立CFRP约束钢筋混凝土圆柱的极限应力、应变计算公式,采用统一的方程形式得到了CFRP约束钢筋混凝土圆柱的单调受压本构模型;通过研究反复受压下加、卸载曲线的规律,结合单调受压应力—应变关系,建立了反复受压下CFRP约束钢筋混凝土圆柱的滞回模型,模型预测结果与试验结果吻合较好;3.首次提出了CFRP约束钢筋混凝土方柱强约束、中等约束及弱约束的界定标准,通过分析试验结果,得到CFRP约束钢筋混凝土方柱中等约束下转折点与极限点应力、应变的计算公式,建立了CFRP中等约束钢筋混凝土方柱的单调受压应力—应变模型;分析了反复受压时卸载及再加载曲线的特征及数学描述,结合单调受压本构关系,建立了反复受压时CFRP约束钢筋混凝土方柱应力—应变关系的滞回模型,模型预测结果与试验结果吻合较好,说明本文所提CFRP中等约束钢筋混凝土方柱单调及滞回本构模型的正确性与适用性。更多还原

【Abstract】 Although extensive researches on the stress-strain models of CFRP-confined concrete columns had been carried out around the world, some questions still exist as follow: (1) most of existing researches focused on CFRP-confined plain concrete and didn’t consider the effect of reinforcment. (2) subsection mode was adopted to describe the constitutive models of CFRP-confined reinforced concrete circular column. (3) there isn’t stress-strain model for CFRP-confined reinforced concrete square columns under medium confinement level. The studies on cyclic axial compression, using for earthquake resistance analysis of structural members, were much fewer. In order to solve above issues, this thesis studies the constitutive models that take the effect of reinforement into consideration through the monotonic and cyclic uniaxial compression experiments of CFRP-confined reinforced concrete circular and square columns. These work provide the technical support for nonlinear analysis of CFRP-confined structures and have important theoretical significance for improvement of seismic Design Code of building. The main contents of the thesis are summarized as follow:1. A total of 20 reinforced concrete circular columns (204 mm in diameter and 612 mm in height) and 18 square columns (204mm in length and 612 mm in height) externally confined with CFRP were tested under monotonic and cyclic uniaxial compression. For circular columns, reinforcment have less effect on stress-stain relationship, but have more effect on square columns and the cyclic compression behavior of circular and square columns. The influence of reinforcement should be considered in stress-strain models of CFRP-confined reinforced concrete circular and square columns.2. The equation of ultimate stress and strain and a new unique stress-strain model were developed for CFRP-confined reinforced concrete circular columns. The rule of unloading and reloading curves in cyclic compression relationship are formed. Combined with monotonic stress-strain model, the cyclic compression model of CFRP-confined reinforced concrete circular column is developed. The predicting results of the proposed model agree well with test datal.3. The standard of describing high-confined, medium-confined and low-confined for CFRP-confined reinforced concrete square column is advised. The equation of stress and strain of feature point and a new stress-strain model were developed for CFRP-confined reinforced concrete square column under medium confinement level. The rule of unloading and reloading curves are simulated based on test results. At last, the cyclic compression model of CFRP-confined reinforced concrete square column is developed considering the monotonic stress-strain model. The predicting results of the proposed model agree well with test data. It shows that the monotonic and cyclic compression models of CFRP-confined reinforced concrete square column under medium confinement level are correct and applicable in the future.更多还原