【作者】 霍宝荣；

【导师】 张向东；

【作者基本信息】 辽宁工程技术大学 ， 工程力学， 2011， 博士

【摘要】 对BFRP-混凝土结构进行了比较系统的试验研究与理论分析,主要内容有三个方面,BFRP筋增强混凝土梁的试验研究;粘贴BFRP布、CFRP布加固RC柱的对比试验研究;粘贴BFRP布加固双曲拱桥提载试验研究,其中粘贴BFRP布加固RC柱试验研究和粘贴BFRP布加固双曲拱桥提载试验研究,在国内外都是首次提出。通过8根直径为9、11、16和19mmBFRP筋试件的拉伸试验,得到BFRP筋增强混凝土梁筋材的拉力-变形曲线关系,抗拉强度和弹性模量等;制作了12根混凝土简支梁,在钢筋和BFRP筋配筋率不同的情况下,进行三分点静力加载直至破坏;制作21根RC圆柱,其中9根BFRP、9根CFRP包裹RC圆柱,3根未进行任何加固的RC短柱,进行轴心抗压对比试验研究;根据BFRP筋的力学特性,结合钢筋混凝土受弯构件的基本理论,对BFRP加筋混凝土简支梁抗弯性能进行有限元分析;在试验研究和理论分析基础上,以现役敖汉危旧双曲拱桥为例,对该桥采用粘贴BFRP布加固后的静动力特性进行研究。本文研究工作可以归结为以下五部分:(1)验证了BFRP筋拉力-变形曲线关系近似成直线关系,抗拉强度随着直径增加而增加,BFRP筋材弹性模量低的特点;并根据BFRP筋抗拉弹性模量低的缺点,建议研制高抗拉弹性模量BFRP筋的方法。(2)根据试验结果建议制造出更好的非剥离BFRP筋;由于BFRP筋的弹性模量小,为避免过早出现较大变形,建议研制预应力BFRP筋增强混凝土梁,以便充分利用BFRP筋抗拉强度高的优点。(3)粘贴BFRP布加固RC柱的承载力提高46.2%～61.7%,粘贴CFRP布加固RC柱承载力提高42.3%～68%,相比之下粘贴CFRP布比粘贴BFRP布后RC柱的承载力提高稍大,但差别不大;粘贴1、2、3层纤维布时,加固RC柱位移延性系数提高幅度分别为1.15、1.98和2.96,可见纤维布粘贴层数越多位移延性系数提高幅度越大;但是研究表明,随着纤维布层数的增加,位移延性系数增长的速度变缓,表明纤维布的使用效率降低,经济粘贴层数为3层;本文基于FRP布约束机理和普通RC柱承载力计算公式提出粘贴BFRP布加固RC柱的承载力计算公式,计算结果与试验结果基本吻合。(4)对BFRP加筋混凝土简支梁抗弯性能进行有限元分析,BFRP加筋混凝土梁荷载-挠度实测与模拟曲线整体走势基本相同;相同荷载时模拟挠度值普遍比实测值大,输入的各项参数均为规范值,说明规范中所给值略为保守;BFRP加筋混凝土梁N 2 N1值为1.17、1.16、1.12,根据结果建议制造出更好的非剥离BFRP筋,使之与混凝土之间有足够的粘结强度。(5)粘贴BFRP布加固双曲拱桥拱肋加固方案可有效降低拱顶、拱脚等关键截面的压应力,增强结构的抗弯及抗扭性能,加固后具有较好的整体工作性能,处于弹性工作状态,荷载增至公路-Ⅱ的1.9倍,已具有足够的安全储备。研究成果对完善FRP-混凝土结构设计理论具有重要的意义,并为BFRP材料在混凝土结构领域的应用提供科学依据,同时为工程实践提供有益指导。更多还原

【Abstract】 The BFRP-concrete structures were experimentally studied and theoretically analyzed systematically. The main contents include two aspects: experimental study on the concrete beam with BFRP reinforcement; comparative study on the RC columns reinforced with BFRP cloth and CFRP cloth; experimental study on improving bearing capacity for the double arch bridge with BFRP cloth. Among which, the experimental study on reinforcing RC column and double arch bridge with BFRP cloth is first proposed at home and abroad.Twelve concrete simple-supported beams were made to conduct the tests of static load with different bars and reinforcement ratio of BFRP bar. In the tests, the loads were applied on three points until the beam was damaged. Twenty-one RC columns were made, including nine RC columns wrapped with BFRP, nine RC columns wrapped with CFRP, three RC columns without any reinforcement, to conduct the comparative study of axial compression. According to the mechanical properties of BFRP and the basic theory about the reinforced concrete flexural members, the finite element analysis is applied to the measurement of the anti-bending properties of the reinforced concrete simple-supported beam with BFRP. Based on the experimental and theoretical study, the static and dynamic properties of solid of the bridge pasted BFRP is researched, taking the dangerous and old arch bridge of Aohan as an example.This research can be divided into five parts:(1)The main physical and mechanical properties are obtained by the tensile test of eight BFRP bars. According to the defect of low tensile elastic modulus of BFRP bar, the study on the BFRP bar with high tensile elastic modulus is recommended.(2)According to the test results, it is recommended to produce the non-stripping BFRP bar and research the enhanced concrete beam with BFRP bar.(3)The result shows that the bearing capacity of the RC columns reinforced with the fibers increases obviously. The bearing capacity of the RC columns with CFRP is higher than that with BFRP, but the difference is not obvious. The displacement ductility factor increases, but its increase rate becomes slow with increasing layers of fiber cloth, so the most economical layer number is 3. Based on the confinement mechanism of FRP cloth and the calculation formula of the bearing capacity for common RC column, the formula of the bearing capacity for reinforced RC column with BFRP cloth is proposed. The result of calculation basically tallies with the number in experiment.(4)The overall trend of the load-deflection curve of concrete beam reinforced with BFRP is basically same as the simulation curve, but the deflections of the simulated values are generally larger than those of the measured values with the same load. The parameters input are specified value, indicating the value of the specification given are somewhat conservative. The values of N 2 N1of the reinforced concrete beam with BFRP are 1.17,1.16 and 1.12 respectively. According to the results, better non-peeling BFRP tendons, which have enough bonding strength with concrete, are suggested to be produced.(5)The test results indicate that the compressive stresses in the vault, the arch spring and other key sections can be effectively reduced by reinforcing the arch rib with BFRP cloth, and the flexural and torsional properties of the structure can be enhanced. The bridge has better whole working performance after being reinforced and it works in the flexible state. Bearing capacity increased to be 1.9 times of road-Ⅱ,having adequate safety margin.The results have great significance on the improvement of theoretical design of concrete structures, and provide the scientific basis for the application of BFRP in the field of concrete structures. At the same time, they can provide beneficial guidance for the engineering practice.更多还原