本文關鍵詞： 嵌入式 預應力 CFRP加固 箱梁 試驗研究 極限承載力　出處：《蘭州交通大學》2014年碩士論文　論文類型：學位論文

【摘要】：碳纖維布加固技術由于擁有良好的技術優(yōu)勢，在結構加固方面得到了較快的發(fā)展及應用。表層嵌入式預應力加固是CFRP布加固技術最新的發(fā)展方向，其兼具嵌入式加固技術及預應力加固技術的眾多優(yōu)點。而混凝土薄壁箱梁由于具有良好的受力性能，在橋梁工程尤其在鐵路中小跨徑簡支梁橋上得到了大量的應用，在長期運營中各種因素引起的鋼筋混凝土薄壁箱梁開裂、承載力下降等影響著箱梁的耐久性，采用有效的加固方式提高箱梁的承載力及耐久性顯得尤其重要。本文結合甘肅省自然科學基金項目《預應力碳纖維加固鋼筋混凝土箱梁的界面應力研究》，在對碳纖維加固技術現(xiàn)階段的研究成果進行分析總結的基礎上，采用嵌入式預應力CFRP布加固技術對RC箱梁進行了抗彎加固，并對其進行了試驗研究、理論分析及數(shù)值模擬。為此，本文開展了如下幾個方面的工作： (1)采用自行研制的碳纖維布預應力張拉錨固裝置，對工程中最常見的單箱單室鋼筋混凝土簡支箱梁進行嵌入式預應力CFRP布抗彎加固，考察了加固試件的破壞模式、受力性能、截面應變分布和撓度變形規(guī)律等。試驗結果表明采用表層嵌入式預應力加固技術，能夠顯著的提高試件的抗彎極限承載能力，改善試件的內(nèi)力和變形分布。 (2)考慮箱梁的剪力滯效應，將翼緣的正應變按N次拋物線分布考慮，在應用剪滯效應的變分法分析結果的基礎上，按彈塑性極限強度準則推導了加固后的箱梁在不同破壞模式下的承載力計算公式，彌補了現(xiàn)有規(guī)范中關于箱形截面加固梁計算公式的不足。分析了加固后箱梁的兩種界限破壞，提出了根據(jù)加固量判斷最終破壞模式的方法。計算結果表明，，本文所提出的理論計算公式具有較高的可信度，其計算值與試驗結果吻合較好。 (3)根據(jù)非線性有限元理論，建立了嵌入式預應力碳纖維布加固鋼筋混凝土簡支箱梁試驗的有限元分析模型，對有限元計算結果與試驗結果進行了對比分析。
[Abstract]:Because of its good technical advantages, CFRP reinforcement technology has been rapidly developed and applied in structural strengthening. The surface embedded prestressing reinforcement is the latest development direction of CFRP reinforcement technology. The concrete thin-walled box girder has been widely used in bridge engineering, especially in railway small and medium-sized span simply supported girder bridge, because of its good mechanical performance. The cracking and bearing capacity of thin-walled reinforced concrete box girder caused by various factors in long-term operation affect the durability of box girder. It is very important to improve the bearing capacity and durability of box girder by using effective reinforcement method. In this paper, the interface stress of reinforced concrete box girder strengthened with prestressed carbon fiber is studied in the light of Gansu Natural Science Foundation project. On the basis of the analysis and summary of the current research results of fiber reinforcement technology, The flexural strengthening of RC box girder is carried out with embedded prestressed CFRP cloth, and the experimental research, theoretical analysis and numerical simulation are carried out. For this reason, the following work is carried out in this paper:. 1) using the prestressing tensioning and anchoring device developed by ourselves, the most common single box single chamber reinforced concrete simply supported box girder is strengthened with embedded prestressing CFRP cloth, and the failure mode and mechanical performance of the strengthened specimen are investigated. The experimental results show that the ultimate bearing capacity of the specimens can be significantly improved and the internal force and deformation distribution of the specimens can be improved by using the surface embedded prestressing reinforcement technology. (2) considering the shear lag effect of box girder, the normal strain of flange is considered according to N parabola distribution, and based on the results of the variational analysis of shear lag effect, According to the ultimate elastoplastic strength criterion, the formulas for calculating the bearing capacity of the strengthened box girder under different failure modes are derived, which make up for the deficiency of the calculation formula of the box section strengthened beam in the existing code. Two kinds of boundary failure of the strengthened box girder are analyzed. The method of judging the ultimate failure mode according to the reinforcement quantity is put forward. The calculation results show that the theoretical formula presented in this paper has a high reliability and the calculated value is in good agreement with the experimental results. According to the nonlinear finite element theory, the finite element analysis model of reinforced concrete simply supported box girder strengthened with embedded prestressed carbon fiber sheet is established, and the finite element calculation results and test results are compared and analyzed.
【學位授予單位】：蘭州交通大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：U441;U445.72

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