【作者】 李宇婧；

【导师】 黄丽华；

【作者基本信息】 大连理工大学 ， 结构工程， 2012， 硕士

【摘要】 目前,国内外学者对纤维复合材料(FRP)加固混凝土结构主要集中在碳纤维复合材料(CFRP)、玻璃纤维复合材料(GFRP)和芳纶纤维复合材料(AFRP)的研究上。玄武岩纤维复合材料(BFRP)作为一种新型加固材料,其强度稍低于CFRP,高于GFRP,延性优于CFRP,耐高温性能明显好于其他三种加固材料。BFRP在土木工程中的研究应用尚处于起步阶段,其力学性能与传统纤维存在差异,需要进行深入研究；现存的计算模型多基于CFRP加固梁和相对有限的试验数据提出,有必要验证这些计算模型对BFRP加固梁的适用性以及对本文试验数据的准确性。本文对不同种类FRP加固混凝土梁进行了试验研究及相应的理论分析,主要研究内容和结论如下：1.通过试验结果对比分析了粘贴BFRP布、CFRP布和GFRP布加固钢筋混凝土梁(RC梁)和未加固普通RC梁的性能差异,并从FRP种类、加载历史与U型布布置方式等方面对比了承载力、延性、应变发展及破坏特征的变化。试验结果表明,在纤维布端部布置U型箍的锚固方式优于沿全梁均布U型箍的锚固方式；碳纤维布加固梁承载力最高延性最低,玻璃纤维布加固梁延性较好但屈服荷载提高不显著,而玄武岩纤维布加固梁承载力得到提高且延性好；当钢筋混凝土梁的破坏由混凝土-胶界面剥离控制时,利用FRP对初始损伤梁进行加固,能更有效发挥FRP材料的抗拉性能,能够有效提高加固梁的延性。2.使用有限元软件ANSYS模拟本文中的钢筋混凝土梁的抗弯加固试验,分别在承载力、刚度和延性、破坏形态以及二次受力性能等方面对试验结果和有限元结果进行了对比分析。本文中的有限元模型可以正确模拟加固梁与未加固梁的开裂荷载,屈服荷载及其相应的挠度变化趋势；可以准确模拟初始损伤对FRP应变的影响；可以给出正确的延性指数,与试验结果吻合良好；本文有限元模型可用于实际模拟。3.根据三个典型的计算方法,Chen&Teng公式,中国规范和ACI指南进行计算,通过对比分析计算解与试验值发现：当钢筋混凝土梁发生剥离破坏时,三种计算方法都过高的估计了碳纤维的加固效果,尤其是ACI建议公式；由于Chen&Teng公式考虑到由中部裂缝引起的界面剥离破坏,与试验破坏模式一致,相比其他两种计算方法,Chen&Teng公式计算结果更接近实验值；当梁的破坏由界面剥离破坏所控制,初始荷载对加固梁的影响不明显,这一点三种计算方法与实验结果一致。更多还原

【Abstract】 At present, domestic and overseas research on concrete structure strengthened with fiber reinforced polymer (FRP) focus on carbon fiber polymer (CFRP), glass fiber polymer (GFRP) and aramid fiber polymer (AFRP). Basalt fiber polymer (BFRP) is a new type of reinforcement material, which owns slightly lower strength and better ductility than CFRP, and larger strength than GFRP. Moreover, BFRP has higher high temperature resistance than other reinforcement materials. Further research is imperative since the restricting number of studies involving BFRP in the civil engineering, as well as the diversity compared with traditional fiber. Due to most of the existing calculation model based on the RC beams strengthened with CFRP and the limit test results, it is essential to verify the feasibility on RC beams bonded with BFRP and the experimental results of this dissertation. Test results and theoretical analysis of RC beams strengthened with various FRP are discussed and investigated in this dissertation. Concretely the main research work and conclusions are summarized as follow:1. Based on the test results, the performance diversity between RC beams strengthened with BFRP, CFRP and GFRP and unreinforced RC beams is discussed, which includes the effects of bearing capacity, ductility and failure type caused by various FRP, loading history and arrangement of U-stirrup. Research shows that strengthened RC beams anchored with U-stirrup at FRP ends offer better reinforcement than that along the beam, and the beams bonded with BFRP exhibit higher bearing capacity than beams bonded with GFRP and better ductility than beams bonded with CFRP. When the reinforcement failure is determined by delamination of epoxy-concrete interface, the strengthening effects on pre-damaged beams are more obvious than intact beam.2. Flexural behaviors of RC beams strengthened with various FRP are simulated via software Ansys. From the aspects of bearing capacity, stiffness and ductility, failure type and initial loading, etc. test results and numerical results are compared. The finite element model adopted in this paper can be used to determine cracking loads, yield loads, the tendency of relevant deflection, the effects of pre-damage on the FRP strain and the valid ductile factors. It is demonstrated that the finite element model proposed in this dissertation is acceptable for simulating strengthened beams. 3. According to three typical algorithmic methods, Chen&Teng formula, China regulation and ACI guide, comparative analysis between calculation and test value indicate that:in the case of peeling failure mode, the strengthening effects of CFRP are overestimated by the three formulas. Reckoning results of Chen&Teng’s formula are much closer to the test results than the other two methods. When interface delamination is considered, Chen&Teng’s formula gives better solution, and both the results of the three computing methods and test indicate that the effects of pre-damage on the RC beams are not obvious.更多还原