【作者】 徐秦；

【导师】 牛荻涛；

【作者基本信息】 西安建筑科技大学 ， 结构工程， 2009， 博士

【摘要】 FRP筋混凝土结构是一种建筑结构新体系，与传统的钢筋相比，FRP筋具有高抗拉强度、低弹性模量及破坏之前的线弹性等特点，因此，用FRP筋等量代替混凝土构件中的钢筋，会引起更大的挠度和裂缝宽度，同时也会造成弯曲强度等的改变。本文通过分析已有的试验研究资料，并采用理论分析、有限元模拟相结合的方法，主要对FRP筋混凝土受弯构件的受力机理、破坏模式、力学模型以及极限承载能力等进行了较为系统的研究。主要研究内容及成果如下：(1)研究总结了FRP筋混凝土结构的基本性能，主要包括FRP筋的组成与特性，以及与混凝土的协同工作的性能等。针对FRP筋混凝土结构延性模型与传统混凝土结构的差异较大特点，分析了FRP筋混凝土结构延性与混凝土强度、FRP筋形式、配筋率等因素之间的关系，给出了FRP筋混凝土结构延性的工程定义，建立了FRP筋混凝土结构延性的计算方法，并通过已有试验数据验证了计算方法的准确性。(2)提出FRP筋混凝土构件的本构关系，采用分离式模型与William-Warnke五参数破坏准则，对FRP筋混凝土结构进行了非线性有限元研究。考虑混凝土和FRP筋之间的相对滑移与钢筋混凝土结构的差异，运用非线性弹簧单元刚度的变化模拟了混凝土与FRP筋之间的粘结性能，建立了较为合理的FRP筋混凝土构件的非线性有限元计算模型。通过该计算模型对FRP筋混凝土受弯构件进行有限元分析，较为真实地模拟了FRP筋混凝土受弯构件的应力、变形，裂缝形成和扩展以及破坏形态和极限承载力，从而为有效的建立FRP筋混凝土受弯构件简化计算方法提供依据。(3)在FRP筋混凝土受弯构件正截面承载力已有试验研究和有限元分析的基础上，对影响FRP筋混凝土受弯构件正截面承载力的因素进行了研究，提出了FRP筋混凝土受弯构件在不同阶段所采取的计算模型，并认为FRP筋混凝土受弯构件计算基本符合平截面假定，运用极限平衡理论建立FRP筋混凝土受弯构件正截面承载力的计算方法，该计算方法较好地考虑了对FRP筋对混凝土受弯构件受力性能的影响，形式简捷且具有明确物理概念，并通过已有试验数据验证了计算方法的准确性。(4)在无腹筋FRP筋混凝土受弯构件受剪性能已有试验研究和有限元分析的基础上，对影响受弯构件斜截面受剪承载力的因素进行了研究。运用拉杆-拱平衡理论，建立了FRP筋混凝土受弯构件斜截面受剪承载力理论计算方法，该计算方法较好地考虑了FRP筋、剪跨比、配箍率对FRP筋混凝土受弯构件受剪性能的影响，形式简捷且具有明确物理概念，并通过已有试验数据验证了计算方法的准确性。(5)通过对FRP筋混凝土受弯构件裂缝和变形的已有试验研究和有限元分析，认为FRP筋混凝土受弯构件裂缝宽度和变形计算可沿用我国现行钢筋混凝土规范中的相关计算方法，但必须对其中系数进行一定的修正。本文通过对FRP筋混凝土受弯构件中材料强度、粘结特性和材料的表面特征系数的等量代换，提出了适合FRP筋混凝土受弯构件裂缝宽度和变形的计算方法，并通过大量的已有试验数据验证了计算方法的准确性。更多还原

【Abstract】 Concrete structure reinforced with fiber reinforced polymer(FRP) bars is a new structural system. Compared with traditional steel, FRP bar has its own superiority, like high tensile strength, low elastic modulus and the characteristics of line flexibility before being damaged. Therefore, instead of using steel bars, concrete structure reinforced with FRP bars can cause a greater deflection and crack width, and also results in changes such as bending strength. The thesis is devoted to study on mechanism, failure mode, mechanical models and ultimate bearing capacity of the concrete beam reinforced FRP bars, on the basis of experimental research; it combined theoretical analysis with finite element simulation. The paper mainly accomplished such work as follows:(1) The thesis summarized the basic functions of concrete structure reinforced with FRP bars, mainly including the composition and the characteristics of FRP bar, as well as the functions of collaborative work with concrete etc. Because ductility model of concrete structure reinforced FRP bars differs from the traditional concrete structure reinforced steel bars, the thesis analyses the relationship between ductility of concrete structure reinforced FRP bars and concrete strength, form of FRP bar as well as reinforcement ratio etc, gives the project definition of ductility of concrete structure reinforced FRP bars, establishes the calculation method of ductility, and verifies the accuracy of the calculation method by experimental data.(2) The thesis studies the concrete structure reinforced with FRP bars by the separate models and William-Warnke five-parameter failure criterion. The bond stress-slip relationship between FRP bars and concrete is advanced. It is studied that the nonlinear finite element model was simulated to analyze FRP reinforced concrete member. Nonlinear finite element analysis was employed to simulate the whole process of changing internal force and deformation, the appearance and development of cracks, and to describe the failure mode and the ultimate strength capacity level. In addition, it also provides some evidences for setting up a simple calculation model of concrete member reinforced with FRP bars.(3) On the basis of experiment and finite element analysis of the normal section bearing capacity of concrete flexural member reinforced with FRP bars, the thesis gives calculation model of concrete flexural member reinforced with FRP bars at different stages and the plane-section assumption. Using the limit equilibrium theory, the thesis establishes the calculation methods of FRP reinforced concrete flexural member which takes FRP bar’s influence into consideration. Meanwhile, this method is simple and has a clear physical concept. The accuracy of the calculation method is proved to be true.(4) On the basis of experiment and finite element analysis of the anti-shear bearing capacity of FRP bars reinforced concrete flexural member without web reinforcement. Using of rod-arch balance theory, the thesis establishes the calculation methods of the anti-shear bearing capacity of FRP reinforced concrete flexural member which takes influence of FRP bar, shear span ratio and the rate of hoop FRP bars into consideration. Meanwhile, this method is simple and has a clear physical concept. The accuracy of the calculation method is proved to be true.(5) Through experiment and finite element analysis of crack width and deformation of concrete flexural member reinforced with FRP bars, the thesis thinks the calculation of the crack width and deformation may also use related in the current Chinese code for design concrete structure reinforced with steel bars, but coefficients of the formula must be amended. The thesis establishes the calculation methods of the crack width and deformation of FRP reinforced concrete flexural member by equivalent substitution of material strength, bonding characteristics and the surface characteristics, and there are a large number of experimental data to verify the accuracy of the calculation method.更多还原