箍筋约束混凝土单轴弹塑性损伤本构模型试验研究

发布时间：2018-08-05 11:33

【摘要】：以往的箍筋约束混凝土试验以研究核心混凝土强度及延性改善为主，其中反复荷载试验多关注加卸载的全过程曲线，较少试验对约束混凝土的损伤劣化行为及量化描述进行研究。为此，本文通过箍筋约束混凝土试验进一步研究混凝土损伤劣化行为，探讨了体积配箍率、混凝土强度和箍筋屈服强度对箍筋约束混凝土损伤劣化规律的影响，并基于已有的损伤劣化方程，给出了约束混凝土损伤劣化方程的具体形式，最终分别建立了矩形箍筋与圆形箍筋两种约束形式下的损伤本构模型。本试验的加载工作在MTS电液伺服系统上完成，通过位移加载控制进行了试件的等应变反复加载和单调加载试验。在等应变反复加载试验中，讨论了混凝土的损伤劣化行为和塑性变形关系；在单调加载试验中，分析了箍筋约束对混凝土强度及延性的改善。通过试验结果，讨论了反复加载应力-应变曲线包络线与单调加载曲线的关系，定量的分析箍筋约束对混凝土强度及延性的改善情况，以混凝土弹性模量退化定义损伤变量，并通过等应变反复加载试验数据定性定量的分析体积配箍率、箍筋屈服强度、混凝土强度对损伤劣化规律的影响。基于试验数据拟合得到了箍筋约束混凝土塑性变形关系，在课题组前期建立的素混凝土损伤劣化方程基础上，引入损伤约束因子C，并通过试验确定了损伤约束因子的形式，最终给出了箍筋约束混凝土的弹塑性损伤本构模型。通过与试验结果对比，本文所建议的损伤劣化方程能较好地反映约束混凝土的损伤劣化行为，所建立的本构模型能够较好地描述箍筋约束混凝土的本构关系。
[Abstract]:Previous tests of confined concrete with stirrups focused on the improvement of strength and ductility of core concrete, and repeated load tests focused on the whole process curve of loading and unloading. The damage deterioration behavior and quantitative description of confined concrete are studied by less experiments. In this paper, the damage deterioration behavior of concrete is further studied by tests of stirrups confined concrete, and the effects of volume hoop ratio, concrete strength and stirrups yield strength on the damage deterioration of stirrups confined concrete are discussed. Based on the existing damage deterioration equation, the concrete form of damage deterioration equation of confined concrete is given. Finally, the damage constitutive models of rectangular stirrups and circular stirrups are established respectively. The loading of the test is completed on the MTS electro-hydraulic servo system. The constant strain repeated loading and monotonic loading of the specimen are carried out by displacement loading control. The relationship between damage deterioration behavior and plastic deformation of concrete is discussed in the experiment of constant strain repeated loading, and the improvement of strength and ductility of concrete by stirrups restraint is analyzed in monotone loading test. Through the test results, the relationship between the envelope of the stress-strain curve under repeated loading and the monotone loading curve is discussed. The improvement of concrete strength and ductility by stirrups is quantitatively analyzed, and the damage variable is defined by the degradation of the elastic modulus of concrete. The effects of volume hoop ratio, yield strength of stirrups and strength of concrete on damage deterioration are analyzed qualitatively and quantitatively by the test data of constant strain repeated loading. Based on the experimental data fitting, the plastic deformation relationship of stirrups confined concrete is obtained. Based on the damage deterioration equation of plain concrete, the damage constraint factor C is introduced, and the form of damage constraint factor is determined by experiments. Finally, the elastoplastic damage constitutive model of stirrups confined concrete is given. Compared with the experimental results, the damage deterioration equation proposed in this paper can better reflect the damage deterioration behavior of confined concrete, and the constitutive model can better describe the constitutive relationship of confined concrete with stirrups.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU375

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