發(fā)布時(shí)間：2018-01-17 16:09

  本文關(guān)鍵詞：預(yù)應(yīng)力碳纖維片材加固混凝土梁膠層粘結(jié)厚度的影響試驗(yàn)研究　出處：《長(zhǎng)沙理工大學(xué)》2014年碩士論文　論文類(lèi)型：學(xué)位論文

  更多相關(guān)文章： 預(yù)應(yīng)力 碳纖維片材 加固 混凝土梁 膠層厚度 界面粘結(jié)應(yīng)力

【摘要】：我國(guó)地域遼闊,國(guó)家對(duì)基礎(chǔ)建設(shè)投入不斷加大,服役橋梁數(shù)量的不斷增加,同時(shí)我國(guó)交通量不斷攀升、自然環(huán)境、結(jié)構(gòu)本身老化等因素導(dǎo)致在役橋梁承載能力難以滿(mǎn)足實(shí)際要求,對(duì)在役橋梁進(jìn)行加固已成為重要研究課題。采用新材料與新工藝對(duì)結(jié)構(gòu)進(jìn)行加固是研究的主流,運(yùn)用預(yù)應(yīng)力FRP加固既有結(jié)構(gòu),不僅充分發(fā)揮FRP材料輕質(zhì)、高強(qiáng)、抗腐蝕等材料特性,而且能較好的提高被加固結(jié)構(gòu)的承載能力、改善被加固結(jié)構(gòu)的工作性能、對(duì)被加固結(jié)構(gòu)自重影響較小等優(yōu)點(diǎn)。而針對(duì)預(yù)應(yīng)力CFRP板材加固混凝土梁在不同初始應(yīng)力條件下膠層粘結(jié)厚度對(duì)被加固結(jié)構(gòu)截面應(yīng)力、CFRP板材放張后界面應(yīng)變分布與CFRP板材界面應(yīng)力分布的影響的研究較少；在此背景下,本文通過(guò)采用9片預(yù)應(yīng)力CFRP板材加固混凝土梁,初始應(yīng)力為CFRP板材抗拉極限承載力的10%、20%與30%,膠層粘結(jié)厚度分別為2mm、4mm與6mm條件下,對(duì)以上問(wèn)題進(jìn)行試驗(yàn)研究,研究表明：1.膠層粘結(jié)厚度對(duì)預(yù)應(yīng)力CFRP板材加固混凝土梁混凝土截面應(yīng)力影響較小,可采用混凝土梁偏心受壓的計(jì)算方法對(duì)放張后混凝土梁跨中截面應(yīng)力分布情況進(jìn)行計(jì)算。2. CFRP板材界面應(yīng)變分布沿板端逐漸增大,當(dāng)達(dá)到一定粘結(jié)長(zhǎng)度時(shí)板材的應(yīng)變趨于穩(wěn)定且與初始應(yīng)變接近,通過(guò)對(duì)CFRP板材界面應(yīng)變數(shù)值擬合得到每片梁CFRP板材界面應(yīng)變的分布情況；提出臨界初始應(yīng)力的定義,初始應(yīng)力達(dá)到某一定值時(shí)板材界面應(yīng)變影響長(zhǎng)度急劇增加,該定值為臨界初始應(yīng)力；不同膠層粘結(jié)厚度臨界初始應(yīng)力不同。3.環(huán)形碳纖維布錨固梁端在錨固處形成界面阻力使錨固處CFRP板材界面應(yīng)力小于臨近錨固處的界面應(yīng)力；環(huán)形端錨對(duì)臨近錨固處的CFRP板材界面應(yīng)力造成界面應(yīng)力滯后現(xiàn)象。4.相同膠層粘結(jié)厚度CFRP板材界面粘結(jié)應(yīng)力-放張力間具有相同數(shù)值關(guān)系,通過(guò)對(duì)試驗(yàn)數(shù)據(jù)進(jìn)行數(shù)值回歸得到不同膠層粘結(jié)厚度的CFRP板材界面粘結(jié)應(yīng)力-放張力計(jì)算式；該計(jì)算式分為非線(xiàn)性上升段與非線(xiàn)線(xiàn)下降段,不同膠層粘結(jié)厚度具有不同的最大CFRP板材界面粘結(jié)應(yīng)力；試驗(yàn)表明膠層粘結(jié)厚度為4mm最為合適,采用外貼CFRP板材加固混凝土結(jié)構(gòu)具有一定參考價(jià)值。
[Abstract]:Our country has a vast territory, the national investment in infrastructure is increasing, the number of service bridges is increasing, at the same time, the traffic volume of our country is rising constantly, and the natural environment. Due to the aging of the structure itself, the bearing capacity of existing bridges is difficult to meet the actual requirements. Strengthening existing bridges has become an important research topic. It is the mainstream of research to use new materials and new technology to strengthen the structure. Using prestressed FRP to strengthen the existing structure, not only give full play to the lightweight, high strength, corrosion resistance and other material characteristics of FRP, but also can improve the bearing capacity of the strengthened structure. Improve the working performance of reinforced structures. It has little influence on the self-weight of reinforced structure, but the bond thickness of adhesive layer on the section stress of strengthened structure under different initial stress conditions is aimed at the prestressed CFRP plate strengthened concrete beam under different initial stress conditions. The influence of strain distribution at the interface of CFRP sheet and the stress distribution at the interface of CFRP sheet is less studied. In this context, 9 pieces of prestressed CFRP plates are used to strengthen concrete beams. The initial stress is 10% and 30% of the ultimate tensile capacity of CFRP plates. When the adhesive thickness of the adhesive layer is 2 mm and 6 mm respectively, the above problems are studied experimentally. The results show that the thickness of adhesive layer has little effect on the section stress of concrete beam strengthened with prestressed CFRP plate. The calculation method of eccentric compression of concrete beam can be used to calculate the stress distribution of the cross section of concrete beam after stretching. 2. The strain distribution at the interface of CFRP plate increases gradually along the end of the slab. When the bond length is reached, the strain of the plate tends to be stable and close to the initial strain. The distribution of the strain at the interface of the CFRP plate is obtained by the numerical fitting of the interfacial strain of each beam. The definition of critical initial stress is put forward. When the initial stress reaches a certain value, the influence length of the interfacial strain on the plate increases sharply, which is the critical initial stress. The critical initial stress of different adhesive thickness is different. 3. The interfacial stress of CFRP plate in Anchorage is smaller than that near Anchorage due to the interfacial resistance formed at the end of annular CFRP Anchorage. The interfacial stress hysteresis phenomenon caused by the annular end anchor on the CFRP plate near the Anchorage. 4. There is the same numerical relationship between the interfacial bond stress and the release tension of the CFRP plate with the same adhesive thickness. The calculation formula of interfacial bond stress-release tension of CFRP plate with different adhesive thickness was obtained by numerical regression of test data. The formula can be divided into nonlinear ascending section and non-linear descending section. Different adhesive thickness of adhesive layer has different maximum bond stress at the interface of CFRP sheet. The test results show that the adhesive thickness of the adhesive layer is 4 mm, and it is of certain reference value to reinforce the concrete structure with the outer CFRP plate.
【學(xué)位授予單位】：長(zhǎng)沙理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類(lèi)號(hào)】：U445.72
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本文編號(hào)：1436961