【作者】 朱春东；

【导师】 何雄君；

【作者基本信息】 武汉理工大学 ， 公路桥梁与渡河工程， 2009， 硕士

【摘要】 现代预应力混凝土结构是随着工程材料的发展而发展起来的在土木工程中有着广泛应用的技术。现在随着纤维增强复合材料在土木工程中的应用越来越广泛,其高强、耐腐蚀等优于普通钢筋的特点,纤维增强复合材料替代钢筋作为混凝土结构的受拉构件有着广阔的发展前景。在常用的纤维增强材料中,CFRP材料具有高强度,高弹性模量,耐腐蚀的特点,在土木工程中应用最为广泛。本文以国内外最新的研究成果为基础,借鉴国内外研究资料,对预应力CFS混凝土梁进行了研究,主要的研究内容如下:首先,本文对预应力CFS混凝土梁进行了有限元分析计算,对预应力CFS混凝土梁的受力特点进行了分析,比较了有无预应力,不同预应力幅度和不同强度的CFS材料对混凝土梁的影响,并与普通CFS混凝土梁的试验结果进行了比较,结果显示预应力CFS能够有效的提高混凝土梁的正常使用承载能力和抗弯刚度,对限制裂缝的宽度也有较大的作用,不同强度的CFS材料对材料的强度利用率有所影响等;其次,根据对预应力CFS混凝土梁的分析研究,特别是预应力CFS混凝土梁的开裂过程的分析,结合国内外的最新研究成果,分为两类情况进行了讨论,分别为CFS端部有机械锚固和无机械锚固,提出了预应力CFS混凝土梁的预应力确定方法,同是应该确保CFS材料在长期工作中不至于应力变化而发生徐变断裂;最后,对预应力CFS混凝土梁的徐变特性做了阐述,对预应力CFS混凝土梁的徐变计算提出了建议,讨论了现有的混凝土徐变模型,并对CFS材料的徐变特性进行了介绍,根据国内外最新的研究成果,认为CFS材料的徐变在相当长的时间内变化很小,故在工程中可不考虑CFS材料本身的徐变,在确保布发生徐变断裂的应力水平下长期性能仍为线性。更多还原

【Abstract】 With the development of the new civil engineering material, the modern prestressed concrete structures become the most popular technique of civil engineering. Nowadays fiber reinforced polymer (FRP) is widely applied in civil engineering, because of the high corrosion resistance and high strength. Fiber reinforced polymer as a substitute tensile structures has broad prospects in the reinforced concrete structures. In common fiber reinforced polymers, the CFRP has the high strength and high young’s modulus, and is widely used in civil engineering.Based on the research of scholars in the domestic and foreign, and used for reference to scholars’ experiments in the domestic and foreign, this essay mainly studied about the prestressed CFS reinforced concrete structures, the specific research is as follows:First, this paper does finite element analysis about prestressed concrete of CFS beams, and prestressed concrete beams of CFS mechanical characteristics are analyzed. Through the analysis of the beams, do some comparisions between the prestressed and unprestressed beams. And also do some researches about the mechanical properties of beams strengthed with different prestressed ratios and strengths of CFS. Results showed that prestressed CFS can improve the bearing capacity and bending stiffness in normal use of concrete beams, and also can limit the width of the cracks. The strength of the CFS does influence in the material strength utilization ratio about the CFS.Secondly, based on the finite element reaserches of the prestressed concrete structures of CFS, espasically the crack increasing carried out the equations to caculation the prestress of the CFS. It is also mentioned that the stress must be lower than the stress due to the creep rupture.Finally, do some reaches on the creep of the prestressed concrete beams of CFS. Also do some discusses on the creep models and the creep characteristic about the CFS itself. Based on the reasearches in the domestic and foreign, most of the reasearchers believe that the creep of the CFS can be ignored in projects.更多还原