本文關(guān)鍵詞： 碳纖維 嵌入式加固 抗彎極限承載力 剪力滯效應(yīng)　出處：《蘭州交通大學(xué)》2014年碩士論文　論文類(lèi)型：學(xué)位論文

【摘要】：工程中常用的混凝土橋梁加固方法有增大截面加固法、粘貼鋼板加固法、體外預(yù)應(yīng)力加固法，，此外，碳纖維憑借其高強(qiáng)、輕質(zhì)、耐腐蝕和施工便利的優(yōu)點(diǎn)，越來(lái)越廣泛地應(yīng)用于混凝土橋梁結(jié)構(gòu)的補(bǔ)強(qiáng)中。近十幾年來(lái)，科研人員對(duì)碳纖維加固鋼筋混凝土結(jié)構(gòu)進(jìn)行了大量的試驗(yàn)研究和理論分析，但是現(xiàn)有的研究大部分局限于矩形梁、T形梁抗彎加固和抗剪加固的研究，而箱梁憑借其結(jié)構(gòu)輕、抗扭剛度大的優(yōu)點(diǎn)在工程實(shí)踐中有廣泛的應(yīng)用，因此研究碳纖維片材加固混凝土箱梁具有重要的現(xiàn)實(shí)意義。另外表層嵌貼加固技術(shù)除了與表層粘貼加固技術(shù)一樣可以提高被加固構(gòu)件的強(qiáng)度和剛度，還可以相對(duì)減少構(gòu)件受惡劣環(huán)境(高溫、高濕和凍融等)的影響，并且能搞提高碳纖維片材的利用率，基于此本文對(duì)嵌貼CFRP加固RC箱梁進(jìn)行了研究，主要研究工作有： (1)以三片鋼筋混凝土箱梁為試驗(yàn)對(duì)象，未加固的箱梁做為對(duì)比梁，外貼碳纖維布加固的箱梁和嵌貼碳纖維布加固的箱梁與之對(duì)比，分別測(cè)量特征截面的撓度、混凝土及碳纖維布的應(yīng)變。通過(guò)試驗(yàn)研究獲得必要的試驗(yàn)數(shù)據(jù)，分析研究嵌貼CFRP布加固RC箱梁的力學(xué)性能。 (2)在現(xiàn)行成熟的鋼筋混凝土梁受彎正截面極限承載力計(jì)算理論基礎(chǔ)上，推導(dǎo)出了嵌貼CFRP布加固RC箱梁的抗彎極限承載力。然而當(dāng)箱型梁在腹板內(nèi)存在壓應(yīng)力時(shí)，其翼板內(nèi)將會(huì)出現(xiàn)剪力滯后效應(yīng)，因此，在傳統(tǒng)的極限承載力理論基礎(chǔ)上，考慮剪力滯的影響，對(duì)嵌貼CFRP布加固RC箱梁的計(jì)算理論進(jìn)行了分析，同時(shí)提出正截面抗彎極限承載力的計(jì)算方法。 (3)以換算截面法為基礎(chǔ)，應(yīng)用變分原理分析了碳纖維布加固鋼筋混凝土簡(jiǎn)支箱梁的剪力滯效應(yīng)，推導(dǎo)出了簡(jiǎn)支箱梁在集中荷載作用下的應(yīng)力計(jì)算公式，并且與前文中的試驗(yàn)值進(jìn)行了對(duì)比，發(fā)現(xiàn)結(jié)果吻合較好。 (4)基于試驗(yàn)和理論分析的結(jié)果，利用大型通用有限元軟件ANSYS建立嵌入式粘貼CFRP布加固RC簡(jiǎn)支箱梁的有限元模型，并將計(jì)算結(jié)果同理論計(jì)算結(jié)果和試驗(yàn)結(jié)果進(jìn)行對(duì)比分析，結(jié)果表明計(jì)算結(jié)果比較接近。
[Abstract]:The common reinforcement methods of concrete bridges in engineering include reinforcement with enlarged section, strengthening with steel plate and external prestressing. In addition, carbon fiber has the advantages of high strength, light weight, corrosion resistance and convenient construction. More and more widely used in the reinforcement of concrete bridge structures. In the past ten years, researchers have carried out a large number of experimental research and theoretical analysis on reinforced concrete structures strengthened with carbon fiber. However, most of the existing studies are limited to the study of bending and shear strengthening of rectangular beams with T-shaped beams. Box girders are widely used in engineering practice because of their advantages of light structure and large torsional stiffness. Therefore, it is of great practical significance to study the reinforcement of concrete box girder with carbon fiber sheet. In addition, the surface embedded reinforcement technology can improve the strength and stiffness of the strengthened members as well as the surface bonding and strengthening technology. It can also reduce the impact of severe environment (high temperature, high humidity, freezing and thawing etc.), and can improve the utilization ratio of carbon fiber sheet. Based on this, the RC box girder strengthened by embedded CFRP is studied, the main research work is as follows:. 1) taking three reinforced concrete box girders as experimental objects, the unreinforced box girders are used as contrast beams, and the box girders strengthened with CFRP and those strengthened with CFRP are compared to each other, and the deflection of characteristic sections is measured respectively. The strain of concrete and carbon fiber sheet. The necessary experimental data were obtained and the mechanical properties of RC box girder strengthened with CFRP cloth were analyzed. 2) based on the mature theory of ultimate bearing capacity of reinforced concrete beams under bending normal section, the ultimate flexural bearing capacity of RC box girder strengthened by encased CFRP cloth is deduced. However, when the box girder has compressive stress in the web, the ultimate bearing capacity of RC box girder is derived. The shear lag effect will occur in the flange. Therefore, based on the traditional ultimate bearing capacity theory and considering the influence of shear lag, the calculation theory of RC box girder strengthened with CFRP cloth is analyzed. At the same time, the calculation method of flexural ultimate bearing capacity of normal section is put forward. Based on the conversion section method, the shear lag effect of reinforced concrete simply supported box girder strengthened with carbon fiber sheet is analyzed by using variational principle, and the stress calculation formula of simply supported box girder under concentrated load is deduced. The results are in good agreement with the experimental data in the previous paper. Based on the results of experiment and theoretical analysis, the finite element model of RC simply supported box girder strengthened with embedded CFRP sheet is established by using the large scale universal finite element software ANSYS, and the calculated results are compared with the theoretical calculation results and the experimental results. The results show that the calculated results are close to each other.
【學(xué)位授予單位】：蘭州交通大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類(lèi)號(hào)】：U441;U445.72

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