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类型 基础研究 预答辩日期 2018-01-19
开始(开题)日期 2015-01-07 论文结束日期 2017-10-11
地点 道桥实验室5楼会议室 论文选题来源 国家自然科学基金项目     论文字数 8.85 (万字)
题目 FRP格栅增强ECC复合加固混凝土梁试验与计算方法研究
主题词 混凝土梁,玄武岩纤维格栅,水泥基复合材料,加固,有限元分析
摘要 针对FRP(Fiber Reinforced Polymer,FRP)材料快速修复与加固钢筋混凝土结构存在的一些问题,提出了使用轻质、高强FRP格栅与高延性ECC(Engineered Cementitious Composite,ECC)相结合的复合加固技术,克服了FRP材料加固技术中存在的环氧树脂胶易于老化,耐高温、耐火性差,以及在潮湿或冻融环境下界面耐久性弱等缺陷。为了明确FRP-ECC复合加固技术工程应用的可行性,本论文结合国家自然科学基金等项目的要求,重点进行了FRP-ECC复合增强钢筋混凝土梁弯曲和剪切性能等方面的研究,主要开展了如下几个方面的研究工作: (1) 开展了42个FRP格栅增强ECC复合层试件的单轴拉伸试验,重点研究了FRP格栅增强率、ECC配合比、水泥基材料中PVA(Polyvinyl Alcohol,PVA)纤维类型以及施工方法等因素对FRP-ECC复合层轴向拉伸力学性能的影响。探讨了FRP格栅与ECC间的粘结性能及FRP-ECC复合层试件的受力特征和破坏类型,明确了FRP-ECC复合层的开裂模式和裂缝扩展方式。 (2) 在FRP格栅增强ECC复合试件轴向拉伸试验研究的基础上,结合已有的研究成果,提出了FRP-ECC复合层轴向拉伸应力-应变本构关系模型及强度模型。与现有的试验数据比较分析表明,本文建立的预测模型与试验曲线走势一致,在开裂点和极限点的预测值与试验值吻合较好,数据离散性较小,可以有效地预测FRP-ECC复合层的轴向受拉应力-应变关系及极限抗拉强度。 (3) 进行了11根玄武岩FRP网格增强ECC复合加固钢筋混凝土梁的弯曲性能试验,重点研究了FRP网格类型、FRP网格增强率、FRP-ECC复合层粘结长度、ECC中PVA纤维掺量、不同加固方法和施工工艺等因素对试验梁弯曲性能的影响。试验结果表明,加固梁主要发生受压区混凝土被压碎破坏、加固层中BFRP网格断裂破坏和FRP-ECC加固层端部剥离破坏三种破坏模式。与普通混凝土对比梁相比,加固试验梁的开裂、屈服和极限荷载提高幅度分别为32%~97%、10%~40%和2%~33%。 (4) 在FRP-ECC复合增强钢筋混凝土梁试验研究的基础上,结合现有规范的要求,建立了FRP-ECC复合增强钢筋混凝土梁抗弯承载力和挠度理论计算模型。与现有试验数据比较分析表明,本文建立的理论模型与试验值吻合较好,数据离散型较低,可以有效的预测FRP-ECC复合增强混凝土梁的弯曲承载力和挠度变形。 (5) 利用大型通用有限元分析软件ABAQUS/Standard,对FRP-ECC复合增强钢筋混凝土梁抗弯性能进行数值模拟,研究了FRP网格类型及增强率、不同加固方法等因素的影响,分析了FRP-ECC复合层与混凝土间的界面粘结性能。研究结果表明,有限元分析结果与试验结果吻合较好,计算精度较高,离散型较小,可以用来预测FRP-ECC复合增强钢筋混凝土梁的弯曲承载力。 (6) 进行了10根玄武岩FRP网格增强ECC复合加固钢筋混凝土梁的抗剪性能试验研究,将FRP加固方法、FRP格栅增强率、剪跨比、ECC中纤维类型及掺量等因素作为试验变量,重点分析了各变量对FRP-ECC复合增强混凝土梁力学性能和破坏机理的影响。试验结果表明,加固梁的破坏模式为剪压破坏和受压区混凝土被压碎破坏,FRP-ECC复合层与混凝土间粘结良好,可以有效抑制混凝土斜裂缝的形成。与普通混凝土对比梁相比,加固试验梁抗剪承载力的提高幅度可达59%。 (7) 在FRP-ECC复合增强钢筋混凝土梁抗剪性能试验研究的基础上,结合已有的研究成果和规范的要求,提出了FRP-ECC复合增强混凝土梁抗剪承载力设计计算方法,并与试验结果进行了对比分析。数据分析表明,本文建立的抗剪承载力理论模型的计算值与试验值吻合较好,数据离散型较小,计算精度较高,可以有效地预测FRP-ECC复合增强混凝土梁的抗剪承载力。 (8) 利用大型通用有限元分析软件ABAQUS/Standard,对FRP-ECC复合增强钢筋混凝土梁抗剪性能进行数值模拟,并对影响加固梁抗剪承载力的剪跨比、FRP网格类型及增强率、不同加固方法、ECC施工工艺及ECC中纤维掺量等因素进行了研究,分析了FRP-ECC复合层与混凝土间的界面粘结性能。数值分析结果表明,有限元分析结果与试验值吻合较好,计算精度较高,数据离散型较小,可以用来预测FRP-ECC复合增强钢筋混凝土梁的受力性能。
英文题目 EXPERIMENT AND CALCULATION METHOD RESEARCH ON REINFORCED CONCRETE (RC) BEAMS STRENGTHENED WITH THE COMPOSITE OF FRP GRID AND ECC
英文主题词 Reinforced Concrete Beam,Basalt Fiber Reinforced Polymer Grid,Cementitious Composite Material,Strengthening,Finite Element Analysis
英文摘要 Aiming at the problems of using fiber reinforced polymer (FRP) to quickly repair and strengthening the reinforced concrete (RC) structures, a new strengthening technique is proposed in this project by combining the FRP grid and ECC as a composite reinforcement layer, which overcomes the disadvantages of FRP strengthening technique, such as aging problem of epoxy resin, poor resistances of high temperature and fire, and poor durability of the interface subjected to humid or freeze thawing environment. To clarify the feasibility of construction application using the FRP-ECC strengthening technique, the flexural and shear behavior of RC beams strengthened with the composite of FRP grid and ECC were explored based on the requirements of National Natural Science Funds and other projects, the main research work of this paper was carried out as follows: (1) The uniaxial tensile test of forty-two FRP grid strengthening ECC specimens were conducted in this paper. The reinforcement ratios of FRP grid, the mixture proportion of ECC, the type of chopped PVA fiber in the cement-based materials, and the construction method were selected as the main test parameters. The bonding behavior of interface between the FRP grid and ECC substrate, the mechanical behavior and failure modes of the FRP-ECC composite were explored, and the cracking pattern and cracking propagation mode of FRP-ECC composite were clarified in this paper. (2) Based on the tensile test results of FRP-ECC composite and the existing research achievement, the stress-strain relationship model and strength model of FRP-ECC composite were proposed to predicate their tensile behavior. It is highlighted that the proposed stress-strain relationship of FRP-ECC composite had a good consistency with the test curve, the predicted cracking load and the ultimate load of FRP-ECC composite agree well with the test data with low levels of data dispersion, which indicated that the proposed models of FRP-ECC composite can be used to effectively predict the tensile stress-strain relationship and ultimate tensile strength of FRP-ECC composite. (3) Eleven RC beams strengthened with the composite of basalt FRP grid and ECC were conducted to investigate their flexural behavior. The types and reinforcement ratios of FRP grid, the bonding length of FRP-ECC composite, the fiber volume of chopped PVA in the ECC layer, the strengthening method, and the construction technology were selected as the main test parameters. The experimental results showed that three failure modes of the strengthened beams were observed during the test, including the concrete crushing at the compressive zone, the rupture of FRP grid in the reinforcement layer, and the end debonding failure of FRP-ECC composite. Compared with the non-strengthened beam, the maximum increase of cracking, yielding and ultimate load of the strengthened beams were 32%~97%, 10%~40% and 2%~33%, respectively. (4) Based on the flexural test results of FRP-ECC strengthening RC beams and the requirements of specifications, the calculation models of flexural load capacity and deflection theory of FRP-ECC strengthening RC beam were proposed to predicte their flexural behavior. The calculated results indicated that the proposed model had a good consistency with the test data with low levels of data dispersion, which can be used to effectively predict the flexural capacity and displacement of FRP-ECC strengthening RC beams. (5) The flexural behavior of RC beams strengthened with the FRP-ECC composite was analysed using the general finite element software of ABAQUS/Standard, the types of FRP grid, the reinforcement ratio of FRP grid, and the strengthening method of ECC were selected as the main test prameters. Moreover, the bonding behavior of the interface between the FRP-ECC composite and concrete substrate was also modeled in this paper. The analysis results highlighted that the calculation results of finite element analysis had a good consistency with the test data with low levels of data dispersion, which can be used to effectively predict the flexural capacity of FRP-ECC strengthening RC beams. (6) Ten RC beams strengthened with the composite of basalt FRP grid and ECC were conducted to investigate their shear behavior. The strengthening methods, the reinforcement ratios of FRP grid, the shear-span ratios of RC beam, and the fiber volume of chopped PVA in the ECC layer were selected as the main test parameters. The effects of these test parameters on the mechanical property and failure mechanism of FRP-ECC strengthening RC beam was analysised in this paper. The experimental results showed that the failure modes of the strengthened beams were shear-compression failure in the shear moment regions and the concrete crushing failure in the pure bending region. The propagation of diagonal cracks was effectively suppressed due to the good bonding performance of the interface between the FRP-ECC composite and concrete substrate. The maximum increase of shear force capacity of the strengthened beams was 59% compared to the non-strengthened beam. (7) Based on the shear test results of FRP-ECC strengthening RC beams and the requirements of specifications, the design and calculation methods of shear bearing capacity of FRP-ECC strengthening RC beam were proposed to predicte their shear behavior. The calculated results indicated that the proposed model of shear bearing capacity had a good consistency with the test data with low levels of data dispersion, which can be used to effectively predict the shear force capacity of FRP-ECC strengthening RC beams. (8) The shear behavior of RC beams strengthened with the FRP-ECC composite was analysed using the general finite element software of ABAQUS/Standard, the types and reinforcement ratio of FRP grid, the shear-span ratio of RC beam, the strengthening method, the construction technology of ECC, the fiber volume of chopped PVA in the ECC layer were selected as the main test prameters. Moreover, the bonding behavior of the interface between the FRP-ECC composite and concrete substrate was also modeled in this paper. The analysis results highlighted that the calculation results of finite element analysis had a good consistency with the test data with low levels of data dispersion, which can be used to effectively predict the shear force capacity of FRP-ECC strengthening RC beams.
学术讨论
主办单位时间地点报告人报告主题
东南大学 (桥梁与隧道工程研究所) 2013.12 东南大学 (道桥试验室5楼会议室) 郑宇宙 高延性可自愈合ECC纤维水泥基 复合材料在桥梁维修加固中的开发与应用
东南大学 2015.01 东南大学 (东南院102) 廖海学 国外钢筋混凝土及预应力结构腐蚀评估及延寿技术
东南大学 (桥梁与隧道工程研究所) 2015.01 东南大学 (道桥试验室5楼会议室) 郑宇宙 纤维格栅网片增强ECC复合加固混凝土梁试验研究和理论分析
昆士兰大学 2015.12 澳大利亚布里斯班 郑宇宙 Tensile Behavior of FRP Grid Strengthening ECC Composite Under a Uniaxial Loading
昆士兰大学 2015.12 澳大利亚布里斯班 郑宇宙 Fatigue Life Prediction of RC Beams Strengthened With Externally Bonded FRP Sheets
中国土木工程学会FRP及工程应用专业委员会 2015.05 中国 重庆 王文炜 BFRP格栅增强ECC加固钢筋混凝土梁抗剪承载力试验研究
东南大学 (桥梁与隧道工程研究所) 2016.05 东南大学 (道桥试验室5楼会议室) 郑宇宙 FRP格栅增强ECC抗弯加固RC梁的试验研究与设计计算方法
中国建筑工业出版社、《建筑钢结构进展》编辑部、《结构工程进展》编委会 2014.09 中国 合肥 王文炜 FRP与混凝土界面粘结性能的试验研究
     
学术会议
会议名称时间地点本人报告本人报告题目
International Institute for FRP in Construction (IIFC) 2015.12 中国 南京 Flexural Strengthening RC Beams Using a Composite Reinforcement Layer: FRP Grid and ECC
International Institute for FRP in Construction (IIFC) 2016.12 中国 香港 Strengthened Reinforced Concrete Beams Using Fiber Reinforced Polymer Grid and Ultra High Toughness Cementitious Composite.
     
代表作
论文名称
Flexural behavior of reinforced concrete beams strengthened with a composite reinforcement layer: BF
Mechanical behavior of ultra-high toughness cementitious composite strengthened with fiber reinforce
 
答辩委员会组成信息
姓名职称导师类别工作单位是否主席备注
黄侨 正高 教授 博导 东南大学 主任委员
叶见曙 正高 教授 博导 东南大学 委员
艾军 正高 教授 博导 南京航空航天大学 委员
魏洋 正高 教授 博导 南京林业大学 委员
万水 正高 教授 博导 东南大学 委员
      
答辩秘书信息
姓名职称工作单位备注
宋晓东 其他 讲师 东南大学 秘书