环向预应力FRP加固混凝土圆柱的主动约束机理研究

发布时间：2018-07-26 14:49

【摘要】：摘要：随着各种工程结构加固改造技术的不断发展,研究人员需要更加精确地评估各种加固技术的作用效果,并建立具有针对性的计算模型。加固混凝土圆柱是工程结构加固改造技术的主要问题之一。由于传统的FRP加固混凝土圆柱技术存在应力滞后问题,而环向预应力FRP加固混凝土圆柱能够对核心混凝土受到主动约束,充分发挥FRP材料的高强性能,避免FRP的应力滞后,从而起到更好的加固效果。故本文进行了环向预应力FRP主动约束混凝土圆柱的试验研究、主动约束机理及损伤演化规律研究,建立针对环向预应力FRP主动约束情况下混凝土圆柱的损伤模型并提出预应力度的建议值,以指导实际工程。 (1)在细观层次上,受压混凝土破坏主要由于混凝土中的骨料与水泥砂浆的泊松比不同,通过变形协调导致混凝土产生损伤。 (2)环向预应力FRP加固混凝土圆柱的轴心受压试验完成了包括对比柱在内的18个试件,研究了预应力大小、混凝土强度等级、截面尺寸和表面处理情况等四个影响因素；使用有限元软件进行数值模拟,分析了主动约束混凝土圆柱的应变演化规律,提出预应力度的建议值为0.2。 (3)从构件层次提出了环向预应力FRP主动约束混凝土圆柱的损伤演化规律。 (4)将损伤变量视为内变量,基于等效应变原理,提出了一个含损伤内变量的构件层次的环向预应力FRP主动约束混凝土圆柱的本构模型,计算值与试验值吻合较好。 (5)证明了高约束比下,环向预应力FRP主动约束混凝土圆柱可不考虑尺寸效应的影响。 (6)证明了对圆柱表面的FRP涂覆浸渍胶增加了试件的承载力和延性性能；对圆柱表面的混凝土打磨处理对试件的静力性能无明显影响。
[Abstract]:Absrtact: with the continuous development of various reinforcement and reconstruction technologies of engineering structures, researchers need to evaluate the effect of various reinforcement techniques more accurately and establish a targeted calculation model. Strengthening concrete columns is one of the main problems in strengthening and reforming engineering structures. Because of the problem of stress lag in the traditional FRP technique for strengthening concrete columns, the RC columns strengthened by circumferential prestressed FRP can be actively confined to the core concrete, which can give full play to the high strength performance of FRP materials and avoid the stress lag of FRP. In order to play a better reinforcement effect. In this paper, the experimental study, the mechanism of active restraint and the law of damage evolution of concrete columns with circumferential prestressed FRP are carried out. The damage model of concrete cylinder under the active restraint of circumferential prestressed FRP is established and the suggested value of prestress degree is put forward to guide the practical engineering. (1) at the mesoscopic level, The failure of compressive concrete is mainly due to the difference of Poisson's ratio between aggregate and cement mortar. Concrete damage is caused by deformation coordination. (2) the axial compression test of concrete columns strengthened by circumferential prestressed FRP has completed 18 specimens, including contrast columns, and studied the size of prestress and the grade of concrete strength. In this paper, the strain evolution law of concrete columns with active confinement is analyzed by using finite element software to simulate the four influencing factors, such as section size and surface treatment. The suggested value of prestress is 0.2. (3) the damage evolution law of RC columns with circumferential prestressed FRP active confinement is proposed from the member level. (4) the damage variable is regarded as an internal variable based on the equivalent strain principle. In this paper, a constitutive model of RC columns with annular prestressed FRP active confinement with internal damage variables is proposed. The calculated values are in good agreement with the experimental values. (5) it is proved that under the high constraint ratio, the constitutive model can be obtained. The effect of size effect can be ignored in the circumferential prestressed FRP active confined concrete cylinder. (6) it is proved that the FRP coating impregnating adhesive on the cylindrical surface increases the bearing capacity and ductility of the specimen; The static properties of the specimens are not affected by the grinding treatment of concrete on the cylindrical surface.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU375.3

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